MD

From Physicians Inpatient Care Specialists (MDICS), Hanover, MD (Dr. Capstack, Ms. Vollono), Versant Statistical Solutions, Raleigh, NC (Ms. Segujja), Anne Arundel Medical Center, Annapolis, MD (Dr. Moser [at the time of the study], Dr. Meisenberg), and Johns Hopkins Hospital, Baltimore, MD (Dr. Michtalik).

Abstract

• Objective: To determine whether a higher than conventional physician assistant (PA)–to-physician hospitalist staffing ratio can achieve similar clinical outcomes for inpatients at a community hospital.
• Methods: Retrospective cohort study comparing 2 hospitalist groups at a 384-bed community hospital, one with a high PA-to-physician ratio model (“expanded PA”), with 3 physicians/3 PAs and the PAs rounding on 14 patients a day (35.73% of all visits), and the other with a low PA-to-physician ratio model (“conventional”), with 9 physicians/2 PAs and the PAs rounding on 9 patients a day (5.89% of all visits). For 16,964 adult patients discharged by the hospitalist groups with a medical principal APR-DRG code between January 2012 and June 2013, in-hospital mortality, cost of care, readmissions, length of stay (LOS) and consultant use were analyzed using logistic regression and adjusted for age, insurance status, severity of illness, and risk of mortality.
• Results: No statistically significant differences were found between the 2 groups for in-hospital mortality (odds ratio [OR], 0.89 [95% confidence interval {CI}, 0.66–1.19]; P = 0.42), readmissions (OR, 0.95 [95% CI, 0.87–1.04]; P = 0.27), length of stay (effect size 0.99 days shorter LOS in expanded PA group, 95% CI, 0.97 to 1.01 days; P = 0.34) or consultant use (OR 1.00, 95% CI 0.94–1.07, P = 0.90). Cost of care was less in the expanded PA group (effect size 3.52% less; estimated cost $2644 vs $2724; 95% CI 2.66%–4.39%, P < 0.001).
• Conclusion: An expanded PA hospitalist staffing model at a community hospital provided similar outcomes at a lower cost of care.

Hospitalist program staffing models must optimize efficiency while maintaining clinical outcomes in order to increase value and decrease costs [1]. The cost of hospitalist programs is burdensome, with nearly 94% of groups nationally requiring financial support beyond professional fees [2]. Nationally, for hospitalist groups serving adults, average institutional support is over $156,000 per physician full time equivalent (FTE) (182 twelve-hour clinical shifts per calendar year) [2]. Significant savings could be achieved if less costly physician assistants could be incorporated into clinical teams to provide similar care without sacrificing quality.

Nurse practitioners (NPs) and physician assistants (PAs) have been successfully employed on academic hospitalist services to complement physician staffing [3–10]. They perform admissions, consults, rounding visits and discharges with physician collaboration as permitted by each group’s policies and in accordance with hospital by-laws and state regulations. A median of 0.25 NP and 0.28 PA FTEs per physician FTE are employed by hospitalist groups that incorporate them, though staffing ratios vary widely [2].

Physicians Inpatient Care Specialists (MDICS) devel-oped a staffing model that deploys PAs to see a large proportion of its patients collaboratively with physicians, and with a higher patient census per PA than has been previously reported [2–5]. The group leaders believed that this would yield similar outcomes for patients at a lower cost to the supporting institution than a conventional staffing model which used fewer PAs to render patient care. Prior inpatient studies have demonstrated comparable clinical outcomes when comparing hospitalist PAs and NPs to residents and fellows [4–10], but to our knowledge no data exist directly comparing hospitalist PAs to hospitalist physicians. This study goes beyond prior work by examining the community, non-teaching setting, and directly comparing outcomes from the expanded use of PAs to those of a hospitalist group staffed with a greater proportion of attending physicians at the same hospital during the same time.

Methods

Setting

The study was performed at Anne Arundel Medical Center (AAMC), a 384-bed community hospital in Annapolis, Maryland, that serves a region of over 1 million people. Approximately 26,000 adult patients are discharged annually. During the study, more than 90% of internal medicine service inpatients were cared for by one of 2 hospitalist groups: a hospital-employed group (“conventional” group, Anne Arundel Medical Group) and a contracted hospitalist group (“expanded PA” group, Physicians Inpatient Care Specialists). The conventional group’s providers received a small incentive for Core Measures compliance for patients with stroke, myocardial infarction, congestive heart failure and pneumonia. The expanded PA group received a flat fee for providing hospitalist services and the group’s providers received a small incentive for productivity from their employer. The study was deemed exempt by the AAMC institutional review board.

Staffing Models, Patient Allocation, and Assignment

Admitted patients were designated to be admitted to one group or the other on the basis of standing arrangements with the patients’ primary care providers. Consultative referrals could also be made from subspecialists, who had discretion as to which group they wished to use.

Each morning, following sign-out report from the night team, each team of day providers determined which patients would be seen by which of their providers. Patients still on service from the previous day would be seen by the same provider again whenever possible in order to maintain continuity. Each individual provider had their own patients for the day who they rounded on independently and were responsible for. Physician involvement with patients seen primarily by PAs occurred as described below. Physicians in both groups were expected to take primary rounding responsibility for patients who were more acute or more complex based on morning sign-out report; there was no more formal mandate for patient allocation to particular provider type.

Physician-PA Collaboration

Patients

Patients discharged between 1 January 2012 and 30 June 2013 by the hospitalist groups were identified by searching AAMC’s Crimson Continuuum of Care (The Advisory Board, Washington, DC), a software analytic tool that is integrated with coded clinical data. Adult patient hospitalizations determined by Crimson to have a medical (non-surgical, non-obstetrical) APR-DRG code as the final principal diagnosis were included. Critically ill patients or those appropriate for “step-down unit” care were cared for by the in-house critical care staff; upon transfer out of critical or step-down care, patients were referred back to the admitting hospitalist team. A diagnosis (and its associated hospitalizations) was excluded for referral bias if the diagnosis was the  principal diagnosis for at least 1% of a group’s discharges and the percentage of patients with that diagnosis was at least two times greater in one group than the other. Hospitalizations with a diagnosis of “ungroupable” (APR-DRG 956) were also excluded.

Measurements

Demographic, insurance status, cost of care, length of stay (LOS), APR-DRG (All Patient Refined Diagnosis-Related Group) severity of illness (SOI) and risk of mortality (ROM), consultant utilization, 30-day all-cause readmission (“readmission rate”), and mortality information was obtained from administrative data and exported into a single database for statistical analysis. Readmissions, inpatient mortality, and cost of care were the primary outcomes; consultant use and length of stay were secondary outcomes. A hospitalization was considered a readmission if the patient returned to inpatient status at AAMC for any reason within 30 days of a previous inpatient discharge. Inpatient mortality was defined as patient death during hospitalization. The cost of care was measured using the case charges associated with each encounter. Charge capture data from both groups was analyzed to classify visits as “physician-only,” “physician co-visit,” and “PA-only” visits. A co-visit consists of the physician visiting the patient after the PA has already done so on the same day, taking their own history and performing their own physical exam, and writing a brief progress note. These data were compared against the exported administrative data to find matching encounters and associated visits, with only matching visits included in the analysis. If a duplicate charge was entered on the same day for a patient, any conflict was resolved in favor of the physician visit. A total of 49,883 and 28,663 matching charges were identified for the conventional and expanded PA groups.

Statistical Methods

Odds of inpatient mortality were calculated using logistic regression and adjusted for age, insurance status, APR-DRG ROM, and LOS. Odds of readmission were calculated using logistic regression and adjusted for age, LOS, insurance and APR-DRG SOI. Cost of care (effect size) was examined using multiple linear regression and adjusted for age, APR-DRG SOI, insurance status and LOS. This model was fit using the logarithmic transformations of cost of care and LOS to correct deviation from normality. Robust regression using MM estimation was used to estimate group effects due to the existence of outliers and high leverage points. Length of stay (effect size) was assessed using the log-transformed variable and adjusted for APR-DRG SOI, age, insurance status and consultant use. Finally, category logistic regression models were fit to estimate the odds of consultant use in the study groups and adjusted for age, LOS, insurance status and APR-DRG SOI.

Results

Records review identified 17,294 adult patient hospitalizations determined by Crimson to have a medical (non-surgical, non-obstetrical) APR-DRG code as the final principal diagnosis.  We excluded 15 expanded PA and 11 conventional hospitalizations that fell under APR-DRG code 956 “ungroupable.” Exclusion for referral bias resulted in the removal of 304 hospitalizations, 207 (3.03%) from the expanded PA group and 97 (0.92%) from the conventional group. These excluded hospitalizations came from 2 APR-DRG codes, urinary stones (code 465) and “other kidney and urinary tract diagnoses” (code 468). This left 6612 hospitalizations in the expanded PA group and 10,352 in the conventional group.

Charge capture data for both groups was used to determine the proportion of encounters rendered by each provider type or combination. In the expanded PA group, 35.73% of visits (10,241 of 28,663) were conducted by a PA, and 64.27% were conducted by a physician or by a PA with a billable physician “co-visit.” In the conventional group, 5.89% of visits (2938 of 49,883) were conducted by a PA, and 94.11% were conducted by a physician only or by a PA with a billable physician “co-visit”.

Readmissions

Overall, 929 of 6612 (14.05%) and 1417 of 10,352 (13.69%) patients were readmitted after being discharged by the expanded PA and conventional groups, respectively. After multivariate analysis, there was no statistically significant difference in odds of readmission between the groups (OR for conventional group, 0.95 [95% CI, 0.87–1.04]; P = 0.27). 

Inpatient Mortality

Unadjusted inpatient mortality for the expanded PA group was 1.30% and 0.99% for the conventional group.  After multivariate analysis, there was no statistically significant difference in odds of in-hospital mortality between the groups (OR for conventional group, 0.89 [95% CI, 0.66–1.19]; P = 0.42).

Patient Charges

The unadjusted mean patient charge in the expanded PA group was $7822 ± $7755 and in the conventional group mean patient charge was $8307 ± 10,034. Multivariate analysis found significantly lower adjusted patient charges in the expanded PA group relative to the conventional group (3.52% lower in the expanded PA group [95% CI, 2.66%–4.39%, P < 0.001). When comparing a “standard” patient who was between 80–89 and had Medicare insurance and an SOI of “major,” the cost of care was $2644 in the expanded PA group vs $2724 in the conventional group.

Length of Stay

Unadjusted mean length of stay was 4.1 ± 3.9 days and 4.3 ± 5.6 days for the expanded PA and conventional groups, respectively. After multivariate analysis, when comparing the statistical model “standard” patient, there was no significant difference in the length of stay between the 2 groups (effect size, 0.99 days shorter LOS in the expanded PA group [95% CI, 0.97–1.01 days]; P = 0.34)

Consultant Use

Utilization of consultants was also assessed. The expanded PA group used a mean of 0.55 consultants per case, and the conventional group used 0.56. After multivariate adjustment, there was no significant difference in consulting service use between groups (OR 1.00 [95% CI, 0.94–1.07]; P = 0.90).

Discussion

Maximizing value and minimizing health care costs is a national priority. To our knowledge, this is the first study to compare hospitalist PAs in a community, non-teaching practice directly and contemporaneously to peer PAs and attending physicians and examine the impact on outcomes. In our study, a much larger proportion of patient visits were conducted primarily by PAs without a same-day physician visit in the expanded PA group (35.73%, vs 5.89% in the conventional group). There was no statistically significant difference in inpatient mortality, length of stay or readmissions. In addition, costs of care measured as hospital charges to patients were lower in the expanded PA group. Consultants were not used disproportionately by the expanded PA group in order to achieve these results. Our results are consistent with studies that have compared PAs and NPs at academic centers to traditional housestaff teams and which show that services staffed with PAs or NPs that provide direct care to medical inpatients are non-inferior [4–10].

This study’s expanded PA group’s PAs rounded on 14 patients per day, close to the “magic 15” that is considered by many a good compromise for hospitalist physicians between productivity and quality [11,12].  This is substantially more than the 6 to 10 patients PAs have been responsible for in previously reported studies [3,4,6]. As the median salary for a PA hospitalist is $102,960 compared with the median internal medicine physician hospitalist salary of $253,977 [2], using hospitalist PAs in a collaboration model as described herein could result in significant savings for supporting institutions without sacrificing quality.

We recognize several limitations to this study. First, the data were obtained retrospectively from a single center and patient assignment between groups was nonrandomized. The significant differences in the baseline characteristics of patients between the study groups, however, were adjusted for in multivariate analysis, and potential referral bias was addressed through our  exclusion criteria. Second, our comparison relied on coding rather than clinical data for diagnosis grouping. However, administrative data is commonly used to determine the primary diagnosis for study patients and the standard for reimbursement. Third, we recognize that there may have been unmeasured confounders that may have affected the outcomes. However, the same resources, including consultants and procedure services, were readily available to both groups and there was no significant difference in consultation rates. Fourth, “cost of care” was measured as overall charges to patients, not cost to the hospital. However, given that all the encounters occurred at the same hospital in the same time frame, the difference should be proportional and equal between groups. Finally, our readmission rates did not account for patients readmitted to other institutions. However, there should not have been a differential effect between the 2 study groups, given the shared patient catchment area and our exclusion for referral bias.

It should also be noted that the expanded PA group used a structured collaboration framework and incorporated a structured education program for its PAs. These components are integral to the expanded PA model, and our results may not be generalizable outside of a similar framework. The expanded PA group’s PAs were carefully selected at the time of hire, specifically educated, and supported through ongoing collaboration to provide efficient and appropriate care at the “top of their licenses”. Not all medical groups will be able to provide this level of support and education, and not all hospitalist PAs will want to and/or be able to reach this level of proficiency. However, successful implementation is entirely achievable for groups that invest the effort. The MDICS education process included 80 hours of didactic sessions spread over several months and is based on the Society of Hospital Medicine Core Competencies [13] as well as 6 months of supervised bedside education with escalating clinical responsibilities under the tutelage of an experienced physician or PA. Year-long academic PA fellowships have also been developed for purposes of similar training at several institutions [14].

Conclusion

Our results show that expanded use of well-educated PAs functioning within a formal collaboration arrangement with physicians provides similar clinical quality to a conventional PA staffing model with no excess patient care costs. The model also allows substantial salary savings to supporting institutions, which is important to hospital and policy stakeholders given the implications for hospitalist group staffing, increasing value, and allocation of precious time and financial resources.

Acknowledgements: The authors wish to thank Kevin Funk, MBA, of MDICS, Clarence Richardson, MBA, of GeBBs Software International, and Heather Channing, Kayla King, and Laura Knox of Anne Arundel Healthcare Enterprise, who provided invaluable help with the data aggregation used for this study.

Corresponding author: Timothy M. Capstack, MD, 7250 Parkway Dr, Suite 500, Hanover, MD 21076, [email protected].

Financial disclosures: Dr. Capstack has ownership interest in Physicians Inpatient Care Specialists (MDICS). Ms. Segujja received compensation from MDICS for statistical analysis.

From Physicians Inpatient Care Specialists (MDICS), Hanover, MD (Dr. Capstack, Ms. Vollono), Versant Statistical Solutions, Raleigh, NC (Ms. Segujja), Anne Arundel Medical Center, Annapolis, MD (Dr. Moser [at the time of the study], Dr. Meisenberg), and Johns Hopkins Hospital, Baltimore, MD (Dr. Michtalik).

Abstract

• Objective: To determine whether a higher than conventional physician assistant (PA)–to-physician hospitalist staffing ratio can achieve similar clinical outcomes for inpatients at a community hospital.
• Methods: Retrospective cohort study comparing 2 hospitalist groups at a 384-bed community hospital, one with a high PA-to-physician ratio model (“expanded PA”), with 3 physicians/3 PAs and the PAs rounding on 14 patients a day (35.73% of all visits), and the other with a low PA-to-physician ratio model (“conventional”), with 9 physicians/2 PAs and the PAs rounding on 9 patients a day (5.89% of all visits). For 16,964 adult patients discharged by the hospitalist groups with a medical principal APR-DRG code between January 2012 and June 2013, in-hospital mortality, cost of care, readmissions, length of stay (LOS) and consultant use were analyzed using logistic regression and adjusted for age, insurance status, severity of illness, and risk of mortality.
• Results: No statistically significant differences were found between the 2 groups for in-hospital mortality (odds ratio [OR], 0.89 [95% confidence interval {CI}, 0.66–1.19]; P = 0.42), readmissions (OR, 0.95 [95% CI, 0.87–1.04]; P = 0.27), length of stay (effect size 0.99 days shorter LOS in expanded PA group, 95% CI, 0.97 to 1.01 days; P = 0.34) or consultant use (OR 1.00, 95% CI 0.94–1.07, P = 0.90). Cost of care was less in the expanded PA group (effect size 3.52% less; estimated cost $2644 vs $2724; 95% CI 2.66%–4.39%, P < 0.001).
• Conclusion: An expanded PA hospitalist staffing model at a community hospital provided similar outcomes at a lower cost of care.

Hospitalist program staffing models must optimize efficiency while maintaining clinical outcomes in order to increase value and decrease costs [1]. The cost of hospitalist programs is burdensome, with nearly 94% of groups nationally requiring financial support beyond professional fees [2]. Nationally, for hospitalist groups serving adults, average institutional support is over $156,000 per physician full time equivalent (FTE) (182 twelve-hour clinical shifts per calendar year) [2]. Significant savings could be achieved if less costly physician assistants could be incorporated into clinical teams to provide similar care without sacrificing quality.

Nurse practitioners (NPs) and physician assistants (PAs) have been successfully employed on academic hospitalist services to complement physician staffing [3–10]. They perform admissions, consults, rounding visits and discharges with physician collaboration as permitted by each group’s policies and in accordance with hospital by-laws and state regulations. A median of 0.25 NP and 0.28 PA FTEs per physician FTE are employed by hospitalist groups that incorporate them, though staffing ratios vary widely [2].

Physicians Inpatient Care Specialists (MDICS) devel-oped a staffing model that deploys PAs to see a large proportion of its patients collaboratively with physicians, and with a higher patient census per PA than has been previously reported [2–5]. The group leaders believed that this would yield similar outcomes for patients at a lower cost to the supporting institution than a conventional staffing model which used fewer PAs to render patient care. Prior inpatient studies have demonstrated comparable clinical outcomes when comparing hospitalist PAs and NPs to residents and fellows [4–10], but to our knowledge no data exist directly comparing hospitalist PAs to hospitalist physicians. This study goes beyond prior work by examining the community, non-teaching setting, and directly comparing outcomes from the expanded use of PAs to those of a hospitalist group staffed with a greater proportion of attending physicians at the same hospital during the same time.

Methods

Setting

The study was performed at Anne Arundel Medical Center (AAMC), a 384-bed community hospital in Annapolis, Maryland, that serves a region of over 1 million people. Approximately 26,000 adult patients are discharged annually. During the study, more than 90% of internal medicine service inpatients were cared for by one of 2 hospitalist groups: a hospital-employed group (“conventional” group, Anne Arundel Medical Group) and a contracted hospitalist group (“expanded PA” group, Physicians Inpatient Care Specialists). The conventional group’s providers received a small incentive for Core Measures compliance for patients with stroke, myocardial infarction, congestive heart failure and pneumonia. The expanded PA group received a flat fee for providing hospitalist services and the group’s providers received a small incentive for productivity from their employer. The study was deemed exempt by the AAMC institutional review board.

Staffing Models, Patient Allocation, and Assignment

Admitted patients were designated to be admitted to one group or the other on the basis of standing arrangements with the patients’ primary care providers. Consultative referrals could also be made from subspecialists, who had discretion as to which group they wished to use.

Each morning, following sign-out report from the night team, each team of day providers determined which patients would be seen by which of their providers. Patients still on service from the previous day would be seen by the same provider again whenever possible in order to maintain continuity. Each individual provider had their own patients for the day who they rounded on independently and were responsible for. Physician involvement with patients seen primarily by PAs occurred as described below. Physicians in both groups were expected to take primary rounding responsibility for patients who were more acute or more complex based on morning sign-out report; there was no more formal mandate for patient allocation to particular provider type.

Physician-PA Collaboration

Patients

Patients discharged between 1 January 2012 and 30 June 2013 by the hospitalist groups were identified by searching AAMC’s Crimson Continuuum of Care (The Advisory Board, Washington, DC), a software analytic tool that is integrated with coded clinical data. Adult patient hospitalizations determined by Crimson to have a medical (non-surgical, non-obstetrical) APR-DRG code as the final principal diagnosis were included. Critically ill patients or those appropriate for “step-down unit” care were cared for by the in-house critical care staff; upon transfer out of critical or step-down care, patients were referred back to the admitting hospitalist team. A diagnosis (and its associated hospitalizations) was excluded for referral bias if the diagnosis was the  principal diagnosis for at least 1% of a group’s discharges and the percentage of patients with that diagnosis was at least two times greater in one group than the other. Hospitalizations with a diagnosis of “ungroupable” (APR-DRG 956) were also excluded.

Measurements

Demographic, insurance status, cost of care, length of stay (LOS), APR-DRG (All Patient Refined Diagnosis-Related Group) severity of illness (SOI) and risk of mortality (ROM), consultant utilization, 30-day all-cause readmission (“readmission rate”), and mortality information was obtained from administrative data and exported into a single database for statistical analysis. Readmissions, inpatient mortality, and cost of care were the primary outcomes; consultant use and length of stay were secondary outcomes. A hospitalization was considered a readmission if the patient returned to inpatient status at AAMC for any reason within 30 days of a previous inpatient discharge. Inpatient mortality was defined as patient death during hospitalization. The cost of care was measured using the case charges associated with each encounter. Charge capture data from both groups was analyzed to classify visits as “physician-only,” “physician co-visit,” and “PA-only” visits. A co-visit consists of the physician visiting the patient after the PA has already done so on the same day, taking their own history and performing their own physical exam, and writing a brief progress note. These data were compared against the exported administrative data to find matching encounters and associated visits, with only matching visits included in the analysis. If a duplicate charge was entered on the same day for a patient, any conflict was resolved in favor of the physician visit. A total of 49,883 and 28,663 matching charges were identified for the conventional and expanded PA groups.

Statistical Methods

Odds of inpatient mortality were calculated using logistic regression and adjusted for age, insurance status, APR-DRG ROM, and LOS. Odds of readmission were calculated using logistic regression and adjusted for age, LOS, insurance and APR-DRG SOI. Cost of care (effect size) was examined using multiple linear regression and adjusted for age, APR-DRG SOI, insurance status and LOS. This model was fit using the logarithmic transformations of cost of care and LOS to correct deviation from normality. Robust regression using MM estimation was used to estimate group effects due to the existence of outliers and high leverage points. Length of stay (effect size) was assessed using the log-transformed variable and adjusted for APR-DRG SOI, age, insurance status and consultant use. Finally, category logistic regression models were fit to estimate the odds of consultant use in the study groups and adjusted for age, LOS, insurance status and APR-DRG SOI.

Results

Records review identified 17,294 adult patient hospitalizations determined by Crimson to have a medical (non-surgical, non-obstetrical) APR-DRG code as the final principal diagnosis.  We excluded 15 expanded PA and 11 conventional hospitalizations that fell under APR-DRG code 956 “ungroupable.” Exclusion for referral bias resulted in the removal of 304 hospitalizations, 207 (3.03%) from the expanded PA group and 97 (0.92%) from the conventional group. These excluded hospitalizations came from 2 APR-DRG codes, urinary stones (code 465) and “other kidney and urinary tract diagnoses” (code 468). This left 6612 hospitalizations in the expanded PA group and 10,352 in the conventional group.

Charge capture data for both groups was used to determine the proportion of encounters rendered by each provider type or combination. In the expanded PA group, 35.73% of visits (10,241 of 28,663) were conducted by a PA, and 64.27% were conducted by a physician or by a PA with a billable physician “co-visit.” In the conventional group, 5.89% of visits (2938 of 49,883) were conducted by a PA, and 94.11% were conducted by a physician only or by a PA with a billable physician “co-visit”.

Readmissions

Overall, 929 of 6612 (14.05%) and 1417 of 10,352 (13.69%) patients were readmitted after being discharged by the expanded PA and conventional groups, respectively. After multivariate analysis, there was no statistically significant difference in odds of readmission between the groups (OR for conventional group, 0.95 [95% CI, 0.87–1.04]; P = 0.27). 

Inpatient Mortality

Unadjusted inpatient mortality for the expanded PA group was 1.30% and 0.99% for the conventional group.  After multivariate analysis, there was no statistically significant difference in odds of in-hospital mortality between the groups (OR for conventional group, 0.89 [95% CI, 0.66–1.19]; P = 0.42).

Patient Charges

The unadjusted mean patient charge in the expanded PA group was $7822 ± $7755 and in the conventional group mean patient charge was $8307 ± 10,034. Multivariate analysis found significantly lower adjusted patient charges in the expanded PA group relative to the conventional group (3.52% lower in the expanded PA group [95% CI, 2.66%–4.39%, P < 0.001). When comparing a “standard” patient who was between 80–89 and had Medicare insurance and an SOI of “major,” the cost of care was $2644 in the expanded PA group vs $2724 in the conventional group.

Length of Stay

Unadjusted mean length of stay was 4.1 ± 3.9 days and 4.3 ± 5.6 days for the expanded PA and conventional groups, respectively. After multivariate analysis, when comparing the statistical model “standard” patient, there was no significant difference in the length of stay between the 2 groups (effect size, 0.99 days shorter LOS in the expanded PA group [95% CI, 0.97–1.01 days]; P = 0.34)

Consultant Use

Utilization of consultants was also assessed. The expanded PA group used a mean of 0.55 consultants per case, and the conventional group used 0.56. After multivariate adjustment, there was no significant difference in consulting service use between groups (OR 1.00 [95% CI, 0.94–1.07]; P = 0.90).

Discussion

Maximizing value and minimizing health care costs is a national priority. To our knowledge, this is the first study to compare hospitalist PAs in a community, non-teaching practice directly and contemporaneously to peer PAs and attending physicians and examine the impact on outcomes. In our study, a much larger proportion of patient visits were conducted primarily by PAs without a same-day physician visit in the expanded PA group (35.73%, vs 5.89% in the conventional group). There was no statistically significant difference in inpatient mortality, length of stay or readmissions. In addition, costs of care measured as hospital charges to patients were lower in the expanded PA group. Consultants were not used disproportionately by the expanded PA group in order to achieve these results. Our results are consistent with studies that have compared PAs and NPs at academic centers to traditional housestaff teams and which show that services staffed with PAs or NPs that provide direct care to medical inpatients are non-inferior [4–10].

This study’s expanded PA group’s PAs rounded on 14 patients per day, close to the “magic 15” that is considered by many a good compromise for hospitalist physicians between productivity and quality [11,12].  This is substantially more than the 6 to 10 patients PAs have been responsible for in previously reported studies [3,4,6]. As the median salary for a PA hospitalist is $102,960 compared with the median internal medicine physician hospitalist salary of $253,977 [2], using hospitalist PAs in a collaboration model as described herein could result in significant savings for supporting institutions without sacrificing quality.

We recognize several limitations to this study. First, the data were obtained retrospectively from a single center and patient assignment between groups was nonrandomized. The significant differences in the baseline characteristics of patients between the study groups, however, were adjusted for in multivariate analysis, and potential referral bias was addressed through our  exclusion criteria. Second, our comparison relied on coding rather than clinical data for diagnosis grouping. However, administrative data is commonly used to determine the primary diagnosis for study patients and the standard for reimbursement. Third, we recognize that there may have been unmeasured confounders that may have affected the outcomes. However, the same resources, including consultants and procedure services, were readily available to both groups and there was no significant difference in consultation rates. Fourth, “cost of care” was measured as overall charges to patients, not cost to the hospital. However, given that all the encounters occurred at the same hospital in the same time frame, the difference should be proportional and equal between groups. Finally, our readmission rates did not account for patients readmitted to other institutions. However, there should not have been a differential effect between the 2 study groups, given the shared patient catchment area and our exclusion for referral bias.

It should also be noted that the expanded PA group used a structured collaboration framework and incorporated a structured education program for its PAs. These components are integral to the expanded PA model, and our results may not be generalizable outside of a similar framework. The expanded PA group’s PAs were carefully selected at the time of hire, specifically educated, and supported through ongoing collaboration to provide efficient and appropriate care at the “top of their licenses”. Not all medical groups will be able to provide this level of support and education, and not all hospitalist PAs will want to and/or be able to reach this level of proficiency. However, successful implementation is entirely achievable for groups that invest the effort. The MDICS education process included 80 hours of didactic sessions spread over several months and is based on the Society of Hospital Medicine Core Competencies [13] as well as 6 months of supervised bedside education with escalating clinical responsibilities under the tutelage of an experienced physician or PA. Year-long academic PA fellowships have also been developed for purposes of similar training at several institutions [14].

Conclusion

Our results show that expanded use of well-educated PAs functioning within a formal collaboration arrangement with physicians provides similar clinical quality to a conventional PA staffing model with no excess patient care costs. The model also allows substantial salary savings to supporting institutions, which is important to hospital and policy stakeholders given the implications for hospitalist group staffing, increasing value, and allocation of precious time and financial resources.

Acknowledgements: The authors wish to thank Kevin Funk, MBA, of MDICS, Clarence Richardson, MBA, of GeBBs Software International, and Heather Channing, Kayla King, and Laura Knox of Anne Arundel Healthcare Enterprise, who provided invaluable help with the data aggregation used for this study.

Corresponding author: Timothy M. Capstack, MD, 7250 Parkway Dr, Suite 500, Hanover, MD 21076, [email protected].

Financial disclosures: Dr. Capstack has ownership interest in Physicians Inpatient Care Specialists (MDICS). Ms. Segujja received compensation from MDICS for statistical analysis.

From Physicians Inpatient Care Specialists (MDICS), Hanover, MD (Dr. Capstack, Ms. Vollono), Versant Statistical Solutions, Raleigh, NC (Ms. Segujja), Anne Arundel Medical Center, Annapolis, MD (Dr. Moser [at the time of the study], Dr. Meisenberg), and Johns Hopkins Hospital, Baltimore, MD (Dr. Michtalik).

Abstract

• Objective: To determine whether a higher than conventional physician assistant (PA)–to-physician hospitalist staffing ratio can achieve similar clinical outcomes for inpatients at a community hospital.
• Methods: Retrospective cohort study comparing 2 hospitalist groups at a 384-bed community hospital, one with a high PA-to-physician ratio model (“expanded PA”), with 3 physicians/3 PAs and the PAs rounding on 14 patients a day (35.73% of all visits), and the other with a low PA-to-physician ratio model (“conventional”), with 9 physicians/2 PAs and the PAs rounding on 9 patients a day (5.89% of all visits). For 16,964 adult patients discharged by the hospitalist groups with a medical principal APR-DRG code between January 2012 and June 2013, in-hospital mortality, cost of care, readmissions, length of stay (LOS) and consultant use were analyzed using logistic regression and adjusted for age, insurance status, severity of illness, and risk of mortality.
• Results: No statistically significant differences were found between the 2 groups for in-hospital mortality (odds ratio [OR], 0.89 [95% confidence interval {CI}, 0.66–1.19]; P = 0.42), readmissions (OR, 0.95 [95% CI, 0.87–1.04]; P = 0.27), length of stay (effect size 0.99 days shorter LOS in expanded PA group, 95% CI, 0.97 to 1.01 days; P = 0.34) or consultant use (OR 1.00, 95% CI 0.94–1.07, P = 0.90). Cost of care was less in the expanded PA group (effect size 3.52% less; estimated cost $2644 vs $2724; 95% CI 2.66%–4.39%, P < 0.001).
• Conclusion: An expanded PA hospitalist staffing model at a community hospital provided similar outcomes at a lower cost of care.

Hospitalist program staffing models must optimize efficiency while maintaining clinical outcomes in order to increase value and decrease costs [1]. The cost of hospitalist programs is burdensome, with nearly 94% of groups nationally requiring financial support beyond professional fees [2]. Nationally, for hospitalist groups serving adults, average institutional support is over $156,000 per physician full time equivalent (FTE) (182 twelve-hour clinical shifts per calendar year) [2]. Significant savings could be achieved if less costly physician assistants could be incorporated into clinical teams to provide similar care without sacrificing quality.

Nurse practitioners (NPs) and physician assistants (PAs) have been successfully employed on academic hospitalist services to complement physician staffing [3–10]. They perform admissions, consults, rounding visits and discharges with physician collaboration as permitted by each group’s policies and in accordance with hospital by-laws and state regulations. A median of 0.25 NP and 0.28 PA FTEs per physician FTE are employed by hospitalist groups that incorporate them, though staffing ratios vary widely [2].

Physicians Inpatient Care Specialists (MDICS) devel-oped a staffing model that deploys PAs to see a large proportion of its patients collaboratively with physicians, and with a higher patient census per PA than has been previously reported [2–5]. The group leaders believed that this would yield similar outcomes for patients at a lower cost to the supporting institution than a conventional staffing model which used fewer PAs to render patient care. Prior inpatient studies have demonstrated comparable clinical outcomes when comparing hospitalist PAs and NPs to residents and fellows [4–10], but to our knowledge no data exist directly comparing hospitalist PAs to hospitalist physicians. This study goes beyond prior work by examining the community, non-teaching setting, and directly comparing outcomes from the expanded use of PAs to those of a hospitalist group staffed with a greater proportion of attending physicians at the same hospital during the same time.

Methods

Setting

The study was performed at Anne Arundel Medical Center (AAMC), a 384-bed community hospital in Annapolis, Maryland, that serves a region of over 1 million people. Approximately 26,000 adult patients are discharged annually. During the study, more than 90% of internal medicine service inpatients were cared for by one of 2 hospitalist groups: a hospital-employed group (“conventional” group, Anne Arundel Medical Group) and a contracted hospitalist group (“expanded PA” group, Physicians Inpatient Care Specialists). The conventional group’s providers received a small incentive for Core Measures compliance for patients with stroke, myocardial infarction, congestive heart failure and pneumonia. The expanded PA group received a flat fee for providing hospitalist services and the group’s providers received a small incentive for productivity from their employer. The study was deemed exempt by the AAMC institutional review board.

Staffing Models, Patient Allocation, and Assignment

Admitted patients were designated to be admitted to one group or the other on the basis of standing arrangements with the patients’ primary care providers. Consultative referrals could also be made from subspecialists, who had discretion as to which group they wished to use.

Each morning, following sign-out report from the night team, each team of day providers determined which patients would be seen by which of their providers. Patients still on service from the previous day would be seen by the same provider again whenever possible in order to maintain continuity. Each individual provider had their own patients for the day who they rounded on independently and were responsible for. Physician involvement with patients seen primarily by PAs occurred as described below. Physicians in both groups were expected to take primary rounding responsibility for patients who were more acute or more complex based on morning sign-out report; there was no more formal mandate for patient allocation to particular provider type.

Physician-PA Collaboration

Patients

Patients discharged between 1 January 2012 and 30 June 2013 by the hospitalist groups were identified by searching AAMC’s Crimson Continuuum of Care (The Advisory Board, Washington, DC), a software analytic tool that is integrated with coded clinical data. Adult patient hospitalizations determined by Crimson to have a medical (non-surgical, non-obstetrical) APR-DRG code as the final principal diagnosis were included. Critically ill patients or those appropriate for “step-down unit” care were cared for by the in-house critical care staff; upon transfer out of critical or step-down care, patients were referred back to the admitting hospitalist team. A diagnosis (and its associated hospitalizations) was excluded for referral bias if the diagnosis was the  principal diagnosis for at least 1% of a group’s discharges and the percentage of patients with that diagnosis was at least two times greater in one group than the other. Hospitalizations with a diagnosis of “ungroupable” (APR-DRG 956) were also excluded.

Measurements

Demographic, insurance status, cost of care, length of stay (LOS), APR-DRG (All Patient Refined Diagnosis-Related Group) severity of illness (SOI) and risk of mortality (ROM), consultant utilization, 30-day all-cause readmission (“readmission rate”), and mortality information was obtained from administrative data and exported into a single database for statistical analysis. Readmissions, inpatient mortality, and cost of care were the primary outcomes; consultant use and length of stay were secondary outcomes. A hospitalization was considered a readmission if the patient returned to inpatient status at AAMC for any reason within 30 days of a previous inpatient discharge. Inpatient mortality was defined as patient death during hospitalization. The cost of care was measured using the case charges associated with each encounter. Charge capture data from both groups was analyzed to classify visits as “physician-only,” “physician co-visit,” and “PA-only” visits. A co-visit consists of the physician visiting the patient after the PA has already done so on the same day, taking their own history and performing their own physical exam, and writing a brief progress note. These data were compared against the exported administrative data to find matching encounters and associated visits, with only matching visits included in the analysis. If a duplicate charge was entered on the same day for a patient, any conflict was resolved in favor of the physician visit. A total of 49,883 and 28,663 matching charges were identified for the conventional and expanded PA groups.

Statistical Methods

Odds of inpatient mortality were calculated using logistic regression and adjusted for age, insurance status, APR-DRG ROM, and LOS. Odds of readmission were calculated using logistic regression and adjusted for age, LOS, insurance and APR-DRG SOI. Cost of care (effect size) was examined using multiple linear regression and adjusted for age, APR-DRG SOI, insurance status and LOS. This model was fit using the logarithmic transformations of cost of care and LOS to correct deviation from normality. Robust regression using MM estimation was used to estimate group effects due to the existence of outliers and high leverage points. Length of stay (effect size) was assessed using the log-transformed variable and adjusted for APR-DRG SOI, age, insurance status and consultant use. Finally, category logistic regression models were fit to estimate the odds of consultant use in the study groups and adjusted for age, LOS, insurance status and APR-DRG SOI.

Results

Records review identified 17,294 adult patient hospitalizations determined by Crimson to have a medical (non-surgical, non-obstetrical) APR-DRG code as the final principal diagnosis.  We excluded 15 expanded PA and 11 conventional hospitalizations that fell under APR-DRG code 956 “ungroupable.” Exclusion for referral bias resulted in the removal of 304 hospitalizations, 207 (3.03%) from the expanded PA group and 97 (0.92%) from the conventional group. These excluded hospitalizations came from 2 APR-DRG codes, urinary stones (code 465) and “other kidney and urinary tract diagnoses” (code 468). This left 6612 hospitalizations in the expanded PA group and 10,352 in the conventional group.

Charge capture data for both groups was used to determine the proportion of encounters rendered by each provider type or combination. In the expanded PA group, 35.73% of visits (10,241 of 28,663) were conducted by a PA, and 64.27% were conducted by a physician or by a PA with a billable physician “co-visit.” In the conventional group, 5.89% of visits (2938 of 49,883) were conducted by a PA, and 94.11% were conducted by a physician only or by a PA with a billable physician “co-visit”.

Readmissions

Overall, 929 of 6612 (14.05%) and 1417 of 10,352 (13.69%) patients were readmitted after being discharged by the expanded PA and conventional groups, respectively. After multivariate analysis, there was no statistically significant difference in odds of readmission between the groups (OR for conventional group, 0.95 [95% CI, 0.87–1.04]; P = 0.27). 

Inpatient Mortality

Unadjusted inpatient mortality for the expanded PA group was 1.30% and 0.99% for the conventional group.  After multivariate analysis, there was no statistically significant difference in odds of in-hospital mortality between the groups (OR for conventional group, 0.89 [95% CI, 0.66–1.19]; P = 0.42).

Patient Charges

The unadjusted mean patient charge in the expanded PA group was $7822 ± $7755 and in the conventional group mean patient charge was $8307 ± 10,034. Multivariate analysis found significantly lower adjusted patient charges in the expanded PA group relative to the conventional group (3.52% lower in the expanded PA group [95% CI, 2.66%–4.39%, P < 0.001). When comparing a “standard” patient who was between 80–89 and had Medicare insurance and an SOI of “major,” the cost of care was $2644 in the expanded PA group vs $2724 in the conventional group.

Length of Stay

Unadjusted mean length of stay was 4.1 ± 3.9 days and 4.3 ± 5.6 days for the expanded PA and conventional groups, respectively. After multivariate analysis, when comparing the statistical model “standard” patient, there was no significant difference in the length of stay between the 2 groups (effect size, 0.99 days shorter LOS in the expanded PA group [95% CI, 0.97–1.01 days]; P = 0.34)

Consultant Use

Utilization of consultants was also assessed. The expanded PA group used a mean of 0.55 consultants per case, and the conventional group used 0.56. After multivariate adjustment, there was no significant difference in consulting service use between groups (OR 1.00 [95% CI, 0.94–1.07]; P = 0.90).

Discussion

Maximizing value and minimizing health care costs is a national priority. To our knowledge, this is the first study to compare hospitalist PAs in a community, non-teaching practice directly and contemporaneously to peer PAs and attending physicians and examine the impact on outcomes. In our study, a much larger proportion of patient visits were conducted primarily by PAs without a same-day physician visit in the expanded PA group (35.73%, vs 5.89% in the conventional group). There was no statistically significant difference in inpatient mortality, length of stay or readmissions. In addition, costs of care measured as hospital charges to patients were lower in the expanded PA group. Consultants were not used disproportionately by the expanded PA group in order to achieve these results. Our results are consistent with studies that have compared PAs and NPs at academic centers to traditional housestaff teams and which show that services staffed with PAs or NPs that provide direct care to medical inpatients are non-inferior [4–10].

This study’s expanded PA group’s PAs rounded on 14 patients per day, close to the “magic 15” that is considered by many a good compromise for hospitalist physicians between productivity and quality [11,12].  This is substantially more than the 6 to 10 patients PAs have been responsible for in previously reported studies [3,4,6]. As the median salary for a PA hospitalist is $102,960 compared with the median internal medicine physician hospitalist salary of $253,977 [2], using hospitalist PAs in a collaboration model as described herein could result in significant savings for supporting institutions without sacrificing quality.

We recognize several limitations to this study. First, the data were obtained retrospectively from a single center and patient assignment between groups was nonrandomized. The significant differences in the baseline characteristics of patients between the study groups, however, were adjusted for in multivariate analysis, and potential referral bias was addressed through our  exclusion criteria. Second, our comparison relied on coding rather than clinical data for diagnosis grouping. However, administrative data is commonly used to determine the primary diagnosis for study patients and the standard for reimbursement. Third, we recognize that there may have been unmeasured confounders that may have affected the outcomes. However, the same resources, including consultants and procedure services, were readily available to both groups and there was no significant difference in consultation rates. Fourth, “cost of care” was measured as overall charges to patients, not cost to the hospital. However, given that all the encounters occurred at the same hospital in the same time frame, the difference should be proportional and equal between groups. Finally, our readmission rates did not account for patients readmitted to other institutions. However, there should not have been a differential effect between the 2 study groups, given the shared patient catchment area and our exclusion for referral bias.

It should also be noted that the expanded PA group used a structured collaboration framework and incorporated a structured education program for its PAs. These components are integral to the expanded PA model, and our results may not be generalizable outside of a similar framework. The expanded PA group’s PAs were carefully selected at the time of hire, specifically educated, and supported through ongoing collaboration to provide efficient and appropriate care at the “top of their licenses”. Not all medical groups will be able to provide this level of support and education, and not all hospitalist PAs will want to and/or be able to reach this level of proficiency. However, successful implementation is entirely achievable for groups that invest the effort. The MDICS education process included 80 hours of didactic sessions spread over several months and is based on the Society of Hospital Medicine Core Competencies [13] as well as 6 months of supervised bedside education with escalating clinical responsibilities under the tutelage of an experienced physician or PA. Year-long academic PA fellowships have also been developed for purposes of similar training at several institutions [14].

Conclusion

Our results show that expanded use of well-educated PAs functioning within a formal collaboration arrangement with physicians provides similar clinical quality to a conventional PA staffing model with no excess patient care costs. The model also allows substantial salary savings to supporting institutions, which is important to hospital and policy stakeholders given the implications for hospitalist group staffing, increasing value, and allocation of precious time and financial resources.

Acknowledgements: The authors wish to thank Kevin Funk, MBA, of MDICS, Clarence Richardson, MBA, of GeBBs Software International, and Heather Channing, Kayla King, and Laura Knox of Anne Arundel Healthcare Enterprise, who provided invaluable help with the data aggregation used for this study.

Corresponding author: Timothy M. Capstack, MD, 7250 Parkway Dr, Suite 500, Hanover, MD 21076, [email protected].

Financial disclosures: Dr. Capstack has ownership interest in Physicians Inpatient Care Specialists (MDICS). Ms. Segujja received compensation from MDICS for statistical analysis.

An 89-year-old woman with a history of coronary artery disease, diabetes mellitus, hypertension, chronic constipation, and glaucoma presented to the ED for evaluation of chest pain and headache. Upon arrival at the ED, the patient also began to experience unrelenting abdominal pain. Abdominal examination showed mild tenderness in the right lower quadrant upon palpation. An abdominal radiograph and a computed tomography (CT) scan were ordered; representative images are presented above (Figure 1a-1d). 

What is the diagnosis? What is the preferred management for this patient? 

Answer

The abdominal radiograph showed no evidence of bowel obstruction. There was, however, a round area of increased density in the pelvis, suggesting the presence of a soft-tissue mass (white arrows, Figure 2) directly adjacent to the sigmoid colon (white asterisk, Figure 2).

Giant Colonic Diverticula

Giant colonic diverticula (GCD) are diverticula larger than 4 cm. This is a rare manifestation of diverticular disease of the bowel and most commonly occurs within the sigmoid colon. The majority of patients who develop GCD are older than age 60 years.¹

The clinical presentation of GCD is nonspecific but can include abdominal pain, vomiting, nausea, and fever in the acute setting.² Chronic presentations of GCD include intermittent abdominal pain, bloating, and constipation. In two-thirds of patients, a palpable abdominal mass is found on physical examination.³

Diagnosis

Due to the nonspecific presentation of GCD, imaging studies are typically required for diagnosis. Although radiographs may show a dilated air-filled structure in the abdomen, differentiation from a normal air-filled bowel may be difficult. Computed tomography is the imaging modality of choice based on its ability to demonstrate the presence of a smooth-walled gas-containing structure that communicates with the bowel lumen. In addition, CT has the ability to visualize the fluid and stool that are often present within the diverticulum. In cases of acute inflammation, diverticular wall thickening also may be present on CT.

Though no longer routinely used, barium enema is another option for diagnosing GCD because it can also demonstrate communication between the giant diverticula and the bowel lumen. However, barium enema is not often used in the emergency setting due to an increased risk of perforation and peritonitis.¹

Management

Complications caused by GCD occur in 15% to 35% of cases and most commonly include perforation with associated peritonitis and abscess formation.⁴ Due to associated morbidity, the preferred treatment is surgical management—even when GCD is found incidentally in asymptomatic patients. In uncomplicated cases, surgical resection of the diverticulum and adjacent colon is performed with primary colic anastomosis. In some cases, a diverting ileostomy is created. In the presence of perforation and/or abscess, percutaneous catheter drainage and two-stage colectomy with colostomy typically is performed.⁵

An 89-year-old woman with a history of coronary artery disease, diabetes mellitus, hypertension, chronic constipation, and glaucoma presented to the ED for evaluation of chest pain and headache. Upon arrival at the ED, the patient also began to experience unrelenting abdominal pain. Abdominal examination showed mild tenderness in the right lower quadrant upon palpation. An abdominal radiograph and a computed tomography (CT) scan were ordered; representative images are presented above (Figure 1a-1d). 

What is the diagnosis? What is the preferred management for this patient? 

Answer

The abdominal radiograph showed no evidence of bowel obstruction. There was, however, a round area of increased density in the pelvis, suggesting the presence of a soft-tissue mass (white arrows, Figure 2) directly adjacent to the sigmoid colon (white asterisk, Figure 2).

Giant Colonic Diverticula

Giant colonic diverticula (GCD) are diverticula larger than 4 cm. This is a rare manifestation of diverticular disease of the bowel and most commonly occurs within the sigmoid colon. The majority of patients who develop GCD are older than age 60 years.¹

The clinical presentation of GCD is nonspecific but can include abdominal pain, vomiting, nausea, and fever in the acute setting.² Chronic presentations of GCD include intermittent abdominal pain, bloating, and constipation. In two-thirds of patients, a palpable abdominal mass is found on physical examination.³

Diagnosis

Due to the nonspecific presentation of GCD, imaging studies are typically required for diagnosis. Although radiographs may show a dilated air-filled structure in the abdomen, differentiation from a normal air-filled bowel may be difficult. Computed tomography is the imaging modality of choice based on its ability to demonstrate the presence of a smooth-walled gas-containing structure that communicates with the bowel lumen. In addition, CT has the ability to visualize the fluid and stool that are often present within the diverticulum. In cases of acute inflammation, diverticular wall thickening also may be present on CT.

Though no longer routinely used, barium enema is another option for diagnosing GCD because it can also demonstrate communication between the giant diverticula and the bowel lumen. However, barium enema is not often used in the emergency setting due to an increased risk of perforation and peritonitis.¹

Management

Complications caused by GCD occur in 15% to 35% of cases and most commonly include perforation with associated peritonitis and abscess formation.⁴ Due to associated morbidity, the preferred treatment is surgical management—even when GCD is found incidentally in asymptomatic patients. In uncomplicated cases, surgical resection of the diverticulum and adjacent colon is performed with primary colic anastomosis. In some cases, a diverting ileostomy is created. In the presence of perforation and/or abscess, percutaneous catheter drainage and two-stage colectomy with colostomy typically is performed.⁵

An 89-year-old woman with a history of coronary artery disease, diabetes mellitus, hypertension, chronic constipation, and glaucoma presented to the ED for evaluation of chest pain and headache. Upon arrival at the ED, the patient also began to experience unrelenting abdominal pain. Abdominal examination showed mild tenderness in the right lower quadrant upon palpation. An abdominal radiograph and a computed tomography (CT) scan were ordered; representative images are presented above (Figure 1a-1d). 

What is the diagnosis? What is the preferred management for this patient? 

Answer

The abdominal radiograph showed no evidence of bowel obstruction. There was, however, a round area of increased density in the pelvis, suggesting the presence of a soft-tissue mass (white arrows, Figure 2) directly adjacent to the sigmoid colon (white asterisk, Figure 2).

Giant Colonic Diverticula

Giant colonic diverticula (GCD) are diverticula larger than 4 cm. This is a rare manifestation of diverticular disease of the bowel and most commonly occurs within the sigmoid colon. The majority of patients who develop GCD are older than age 60 years.¹

The clinical presentation of GCD is nonspecific but can include abdominal pain, vomiting, nausea, and fever in the acute setting.² Chronic presentations of GCD include intermittent abdominal pain, bloating, and constipation. In two-thirds of patients, a palpable abdominal mass is found on physical examination.³

Diagnosis

Due to the nonspecific presentation of GCD, imaging studies are typically required for diagnosis. Although radiographs may show a dilated air-filled structure in the abdomen, differentiation from a normal air-filled bowel may be difficult. Computed tomography is the imaging modality of choice based on its ability to demonstrate the presence of a smooth-walled gas-containing structure that communicates with the bowel lumen. In addition, CT has the ability to visualize the fluid and stool that are often present within the diverticulum. In cases of acute inflammation, diverticular wall thickening also may be present on CT.

Though no longer routinely used, barium enema is another option for diagnosing GCD because it can also demonstrate communication between the giant diverticula and the bowel lumen. However, barium enema is not often used in the emergency setting due to an increased risk of perforation and peritonitis.¹

Management

Complications caused by GCD occur in 15% to 35% of cases and most commonly include perforation with associated peritonitis and abscess formation.⁴ Due to associated morbidity, the preferred treatment is surgical management—even when GCD is found incidentally in asymptomatic patients. In uncomplicated cases, surgical resection of the diverticulum and adjacent colon is performed with primary colic anastomosis. In some cases, a diverting ileostomy is created. In the presence of perforation and/or abscess, percutaneous catheter drainage and two-stage colectomy with colostomy typically is performed.⁵

Case

A 39-year-old woman, previously in good health, presented to the ED with a chief complaint of severe sore throat, which she said had begun approximately 4 hours prior and was rapidly worsening. She thought her voice sounded muffled, and said she was now having difficulty swallowing her saliva. The patient denied fever but did admit to chills. She experienced onset of shortness of breath 30 minutes prior to arrival to the ED.

The patient stated that she was a house painter and had been working in the home of someone who had several dogs. While not previously allergic to animals, the patient was concerned exposure to the dogs might have contributed to her symptoms. Regarding her social history, the patient admitted to daily consumption of beer, but denied smoking cigarettes. She had no known drug allergies.

On physical examination, the patient was afebrile. Her vital signs were: heart rate, 125 beats/min; blood pressure, 137/74 mm Hg; and respiratory rate, 18 breaths/min. Oxygen saturation was 99% on room air. Overall, the patient appeared anxious and exhibited mild inspiratory stridor. Examination of the eyes and ears were normal. There was no obvious inflammation or swelling of the posterior pharynx; the tongue was normal; there was no swelling of the floor of the mouth; and the uvula was midline and without swelling.

The patient was noted to having difficulty handling her secretions. She exhibited full range of motion of her neck. Her trachea was tender upon palpation but without jugular venous distension or lymphadenopathy. The cardiac examination was significant for tachycardia with a regular rhythm and without murmurs, rubs, or gallops; the pulmonary examination was normal except for transmitted upper airway sounds. The patient’s abdominal, dermatological, and neurological examinations were all normal.

Based on the examination findings, the differential diagnosis included allergic reaction, angioedema, epiglottitis, and retropharyngeal abscess. An intravenous (IV) line was placed and blood was drawn for laboratory evaluation, which included a complete blood count, basic metabolic panel (BMP), and a quantitative pregnancy test. Given the patient’s history, the emergency physician (EP) was most concerned for an allergic reaction, and administered epinephrine 0.5 mg (1:1,000) intramuscularly (IM) in the mid-anterolateral thigh, in addition to methylprednisolone, 125 mg; diphenhydramine, 25 mg; and famotidine, 20 mg IV.

A portable soft-tissue lateral radiograph of the neck was obtained. Radiology services interpreted the film as showing “prominent prevertebral soft tissues and epiglottis.

Discussion

While the incidence of pediatric epiglottitis has decreased since the introduction of the Haemophilus influenzae type b (Hib) vaccine in 1985, adult epiglottitis continues to represent a potentially life-threatening condition whose incidence has remained constant over the past several decades.^1,2 The incidence of supraglottitis in adults is now 2.5 times greater than the incidence in children.^3,4

Several important differences exist in the presentation and management of adults who present with inflammation of the epiglottis as compared to children. Children commonly present with an acute onset of symptoms, and due to their smaller and more pliant airway anatomy, they often experience stridor and respiratory distress.^3,5 The inflammation in children is typically confined to the epiglottis and aryepiglottic folds, while in adults the inflammation can affect not only the epiglottis, but also supraglottic structures such as the pharynx, uvula, and aryepiglottic folds. For this reason, in adults the condition is often referred to as “supraglottitis.”^2,6 Adults with supraglottitis most likely present in their 30s, 40s, and 50s, while children present between the ages of 2 and 5 years old.^1,3,7 In adults, men more commonly present with supraglottitis than women.^1,2 Cigarette smokers and patients with hypertension, diabetes mellitus (DM), chronic obstructive pulmonary disease, or human immunodeficiency virus/AIDS are at increased risk for supraglottitis.^3,4 The mortality rate for adults with supraglottitis ranges from 1.2% to 7.1%.³

Etiology

Prior to the use of the Hib vaccine, Hib was the most common cause of epiglottitis, and remains so for children.¹ Currently, the most common cause of supraglottitis in adults is Group A beta-hemolytic Streptococci.² Other etiologies include other bacteria (Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas species, Klebsiella pneumoniae, Pasteurella multocida, Neisseria species), viruses (herpes simplex, varicella, parainfluenza), trauma, and thermal injuries.^1,4,5,8

Signs and Symptoms

Throat pain, dysphagia, odynophagia, and muffled voice are common complaints of adults presenting to the ED with supraglottitis.^2,7 Fever is usually, but not always, present; the complaint of cough, however, is rare.^2,3,4 Other less frequent complaints include hoarseness and drooling. Adults can also present with cervical lymphadenopathy, anterior neck tenderness, and cellulitis of the neck and chest.^2,4 In general, the more severe cases will progress rapidly over a few hours. Due to the larger anatomy in adults, they are more likely than children to experience a gradual progression of symptoms, and supraglottitis will be missed on the initial presentation in up to 50% of adults.^3,4 Stridor or respiratory compromise does occur in a minority of adult patients with supraglottitis. The need for artificial airway support (ie, endotracheal intubation, cricothyroidotomy) in adults ranges from 6.6% to 16%.^9,10

Making the Diagnosis

The gold standard for diagnosing supraglottitis is direct laryngoscopy.^3,4 This point is emphasized in our case report, since the CT scan was concerning for a retropharyngeal abscess, and not supraglottitis. The examination of the oropharynx is generally safer and better tolerated in adults compared to pediatric patients, since airway compromise is much less likely. On occasion, inflammation, erythema, and edema of the epiglottis, aryepiglottic folds, or arytenoid cartilages can be observed.⁵ More commonly, the supraglottic structures are not visualized, and the posterior oropharynx appears relatively normal. This should serve as a clue for possible supraglottitis.

In suspected cases of adult supraglottitis without emergent airway compromise, lateral soft-tissue radiographs can be obtained to look for the “thumb sign,” indicating a swollen epiglottis. In adult supraglottitis, the width of the epiglottis is usually greater than 8 mm.¹¹ Other abnormal radiographic findings include arytenoid and aryepiglottic fold enlargement, thinning of the airway, and an increase in size of the prevertebral space. Plain film sensitivity rates range from 38% to 98%.

Complete blood count and throat cultures are not particularly helpful in adult cases. Blood cultures, while only about 30% sensitive in adults, should be considered as supraglottitis can result in secondary infection in the central nervous system, lungs, and surrounding structures.^3,5

If available, otolaryngology services should be consulted to evaluate the airway, and IV antibiotics, such as a third-generation cephalosporin (eg, ceftriaxone, cefotaxime), should be initiated to include coverage of Hib.³ If methicillin-resistant S aureus is a concern, vancomycin should be added. Clindamycin or metronidazole should also be given if anaerobes are suspected.^4,7 The location for performing the nasopharyngeal laryngoscopy varies, depending on the patient’s age (ie, pediatric vs adult), severity of symptoms, presence of airway compromise, and local practice and custom.

Advanced imaging studies (CT scan or magnetic resonance imaging) can help identify the presence of an abscess and delineate the extent of the infection, but are not indicated in the early diagnosis and management of suspected adult supraglottitis.⁴ As our case demonstrates, CT is neither highly sensitive nor specific for the diagnosis of epiglottitis. The role of ultrasound in the evaluation of suspected epiglottitis is still being developed. One recent study compared 15 healthy volunteers with 15 patients diagnosed with epiglottitis by an otolaryngologist using laryngoscopy.¹² A statistically significant difference was observed in the anteroposterior diameter of the epiglottis at the midpoint and both lateral edges between the study subjects and healthy volunteers.¹² While there was overlap in the ranges for the midpoint, there was no overlap in both lateral edges between the two groups.¹²

Treatment

The vast majority of adult cases of supraglottitis are managed medically without airway intervention. Patients presenting with a rapid onset of symptoms and in respiratory distress or with stridor, drooling, or cyanosis, should be managed with early airway intervention. The use of corticosteroids is controversial, and has not been proven beneficial in any prospective trials.^1-4,6,7,13

Admission to a critical care unit is indicated initially, even in patients who are not intubated, as they can experience delayed airway compromise with progression of the infection and edema.¹³

Complications

Abscess formation is a serious complication of supraglottitis, is present in up to 30% of cases, and is more likely to be seen in adults than in children.¹³ Since the adult larynx and surrounding tissues are larger than in children, often the infection is present longer, which allows for an abscess to develop. The risk of abscess formation is increased in patients with DM or those in whom a foreign body is present.

Numerous organisms have been isolated from supraglottic abscesses in adults, and in addition to incision and drainage, antibiotics covering both gram-positive organisms and anaerobes should be initiated.⁵ The presence of a supraglottic abscess increases the need for emergent intubation.¹³ In addition, a supraglottic abscess increases the mortality rate to 30%.³ Other complications from supraglottitis include mediastinitis, cervical adenitis, meningitis, and pneumonia.^4,5

Conclusion

While the incidence of epiglottitis in the pediatric patient population has fallen, the incidence in adults remains relatively stable. Clinicians should consider supraglottitis in the differential diagnosis of adults presenting with severe sore throat, dysphagia, or stridor. While airway compromise in adults is uncommon, it does occur. Soft-tissue lateral neck radiographs can help make the diagnosis, but the gold standard remains laryngoscopy. All patients should be started on IV antibiotics and admitted to the ICU initially for airway watch.

Case

A 39-year-old woman, previously in good health, presented to the ED with a chief complaint of severe sore throat, which she said had begun approximately 4 hours prior and was rapidly worsening. She thought her voice sounded muffled, and said she was now having difficulty swallowing her saliva. The patient denied fever but did admit to chills. She experienced onset of shortness of breath 30 minutes prior to arrival to the ED.

The patient stated that she was a house painter and had been working in the home of someone who had several dogs. While not previously allergic to animals, the patient was concerned exposure to the dogs might have contributed to her symptoms. Regarding her social history, the patient admitted to daily consumption of beer, but denied smoking cigarettes. She had no known drug allergies.

On physical examination, the patient was afebrile. Her vital signs were: heart rate, 125 beats/min; blood pressure, 137/74 mm Hg; and respiratory rate, 18 breaths/min. Oxygen saturation was 99% on room air. Overall, the patient appeared anxious and exhibited mild inspiratory stridor. Examination of the eyes and ears were normal. There was no obvious inflammation or swelling of the posterior pharynx; the tongue was normal; there was no swelling of the floor of the mouth; and the uvula was midline and without swelling.

The patient was noted to having difficulty handling her secretions. She exhibited full range of motion of her neck. Her trachea was tender upon palpation but without jugular venous distension or lymphadenopathy. The cardiac examination was significant for tachycardia with a regular rhythm and without murmurs, rubs, or gallops; the pulmonary examination was normal except for transmitted upper airway sounds. The patient’s abdominal, dermatological, and neurological examinations were all normal.

Based on the examination findings, the differential diagnosis included allergic reaction, angioedema, epiglottitis, and retropharyngeal abscess. An intravenous (IV) line was placed and blood was drawn for laboratory evaluation, which included a complete blood count, basic metabolic panel (BMP), and a quantitative pregnancy test. Given the patient’s history, the emergency physician (EP) was most concerned for an allergic reaction, and administered epinephrine 0.5 mg (1:1,000) intramuscularly (IM) in the mid-anterolateral thigh, in addition to methylprednisolone, 125 mg; diphenhydramine, 25 mg; and famotidine, 20 mg IV.

A portable soft-tissue lateral radiograph of the neck was obtained. Radiology services interpreted the film as showing “prominent prevertebral soft tissues and epiglottis.

Discussion

While the incidence of pediatric epiglottitis has decreased since the introduction of the Haemophilus influenzae type b (Hib) vaccine in 1985, adult epiglottitis continues to represent a potentially life-threatening condition whose incidence has remained constant over the past several decades.^1,2 The incidence of supraglottitis in adults is now 2.5 times greater than the incidence in children.^3,4

Several important differences exist in the presentation and management of adults who present with inflammation of the epiglottis as compared to children. Children commonly present with an acute onset of symptoms, and due to their smaller and more pliant airway anatomy, they often experience stridor and respiratory distress.^3,5 The inflammation in children is typically confined to the epiglottis and aryepiglottic folds, while in adults the inflammation can affect not only the epiglottis, but also supraglottic structures such as the pharynx, uvula, and aryepiglottic folds. For this reason, in adults the condition is often referred to as “supraglottitis.”^2,6 Adults with supraglottitis most likely present in their 30s, 40s, and 50s, while children present between the ages of 2 and 5 years old.^1,3,7 In adults, men more commonly present with supraglottitis than women.^1,2 Cigarette smokers and patients with hypertension, diabetes mellitus (DM), chronic obstructive pulmonary disease, or human immunodeficiency virus/AIDS are at increased risk for supraglottitis.^3,4 The mortality rate for adults with supraglottitis ranges from 1.2% to 7.1%.³

Etiology

Prior to the use of the Hib vaccine, Hib was the most common cause of epiglottitis, and remains so for children.¹ Currently, the most common cause of supraglottitis in adults is Group A beta-hemolytic Streptococci.² Other etiologies include other bacteria (Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas species, Klebsiella pneumoniae, Pasteurella multocida, Neisseria species), viruses (herpes simplex, varicella, parainfluenza), trauma, and thermal injuries.^1,4,5,8

Signs and Symptoms

Throat pain, dysphagia, odynophagia, and muffled voice are common complaints of adults presenting to the ED with supraglottitis.^2,7 Fever is usually, but not always, present; the complaint of cough, however, is rare.^2,3,4 Other less frequent complaints include hoarseness and drooling. Adults can also present with cervical lymphadenopathy, anterior neck tenderness, and cellulitis of the neck and chest.^2,4 In general, the more severe cases will progress rapidly over a few hours. Due to the larger anatomy in adults, they are more likely than children to experience a gradual progression of symptoms, and supraglottitis will be missed on the initial presentation in up to 50% of adults.^3,4 Stridor or respiratory compromise does occur in a minority of adult patients with supraglottitis. The need for artificial airway support (ie, endotracheal intubation, cricothyroidotomy) in adults ranges from 6.6% to 16%.^9,10

Making the Diagnosis

The gold standard for diagnosing supraglottitis is direct laryngoscopy.^3,4 This point is emphasized in our case report, since the CT scan was concerning for a retropharyngeal abscess, and not supraglottitis. The examination of the oropharynx is generally safer and better tolerated in adults compared to pediatric patients, since airway compromise is much less likely. On occasion, inflammation, erythema, and edema of the epiglottis, aryepiglottic folds, or arytenoid cartilages can be observed.⁵ More commonly, the supraglottic structures are not visualized, and the posterior oropharynx appears relatively normal. This should serve as a clue for possible supraglottitis.

In suspected cases of adult supraglottitis without emergent airway compromise, lateral soft-tissue radiographs can be obtained to look for the “thumb sign,” indicating a swollen epiglottis. In adult supraglottitis, the width of the epiglottis is usually greater than 8 mm.¹¹ Other abnormal radiographic findings include arytenoid and aryepiglottic fold enlargement, thinning of the airway, and an increase in size of the prevertebral space. Plain film sensitivity rates range from 38% to 98%.

Complete blood count and throat cultures are not particularly helpful in adult cases. Blood cultures, while only about 30% sensitive in adults, should be considered as supraglottitis can result in secondary infection in the central nervous system, lungs, and surrounding structures.^3,5

If available, otolaryngology services should be consulted to evaluate the airway, and IV antibiotics, such as a third-generation cephalosporin (eg, ceftriaxone, cefotaxime), should be initiated to include coverage of Hib.³ If methicillin-resistant S aureus is a concern, vancomycin should be added. Clindamycin or metronidazole should also be given if anaerobes are suspected.^4,7 The location for performing the nasopharyngeal laryngoscopy varies, depending on the patient’s age (ie, pediatric vs adult), severity of symptoms, presence of airway compromise, and local practice and custom.

Advanced imaging studies (CT scan or magnetic resonance imaging) can help identify the presence of an abscess and delineate the extent of the infection, but are not indicated in the early diagnosis and management of suspected adult supraglottitis.⁴ As our case demonstrates, CT is neither highly sensitive nor specific for the diagnosis of epiglottitis. The role of ultrasound in the evaluation of suspected epiglottitis is still being developed. One recent study compared 15 healthy volunteers with 15 patients diagnosed with epiglottitis by an otolaryngologist using laryngoscopy.¹² A statistically significant difference was observed in the anteroposterior diameter of the epiglottis at the midpoint and both lateral edges between the study subjects and healthy volunteers.¹² While there was overlap in the ranges for the midpoint, there was no overlap in both lateral edges between the two groups.¹²

Treatment

The vast majority of adult cases of supraglottitis are managed medically without airway intervention. Patients presenting with a rapid onset of symptoms and in respiratory distress or with stridor, drooling, or cyanosis, should be managed with early airway intervention. The use of corticosteroids is controversial, and has not been proven beneficial in any prospective trials.^1-4,6,7,13

Admission to a critical care unit is indicated initially, even in patients who are not intubated, as they can experience delayed airway compromise with progression of the infection and edema.¹³

Complications

Abscess formation is a serious complication of supraglottitis, is present in up to 30% of cases, and is more likely to be seen in adults than in children.¹³ Since the adult larynx and surrounding tissues are larger than in children, often the infection is present longer, which allows for an abscess to develop. The risk of abscess formation is increased in patients with DM or those in whom a foreign body is present.

Numerous organisms have been isolated from supraglottic abscesses in adults, and in addition to incision and drainage, antibiotics covering both gram-positive organisms and anaerobes should be initiated.⁵ The presence of a supraglottic abscess increases the need for emergent intubation.¹³ In addition, a supraglottic abscess increases the mortality rate to 30%.³ Other complications from supraglottitis include mediastinitis, cervical adenitis, meningitis, and pneumonia.^4,5

Conclusion

While the incidence of epiglottitis in the pediatric patient population has fallen, the incidence in adults remains relatively stable. Clinicians should consider supraglottitis in the differential diagnosis of adults presenting with severe sore throat, dysphagia, or stridor. While airway compromise in adults is uncommon, it does occur. Soft-tissue lateral neck radiographs can help make the diagnosis, but the gold standard remains laryngoscopy. All patients should be started on IV antibiotics and admitted to the ICU initially for airway watch.

Case

A 39-year-old woman, previously in good health, presented to the ED with a chief complaint of severe sore throat, which she said had begun approximately 4 hours prior and was rapidly worsening. She thought her voice sounded muffled, and said she was now having difficulty swallowing her saliva. The patient denied fever but did admit to chills. She experienced onset of shortness of breath 30 minutes prior to arrival to the ED.

The patient stated that she was a house painter and had been working in the home of someone who had several dogs. While not previously allergic to animals, the patient was concerned exposure to the dogs might have contributed to her symptoms. Regarding her social history, the patient admitted to daily consumption of beer, but denied smoking cigarettes. She had no known drug allergies.

On physical examination, the patient was afebrile. Her vital signs were: heart rate, 125 beats/min; blood pressure, 137/74 mm Hg; and respiratory rate, 18 breaths/min. Oxygen saturation was 99% on room air. Overall, the patient appeared anxious and exhibited mild inspiratory stridor. Examination of the eyes and ears were normal. There was no obvious inflammation or swelling of the posterior pharynx; the tongue was normal; there was no swelling of the floor of the mouth; and the uvula was midline and without swelling.

The patient was noted to having difficulty handling her secretions. She exhibited full range of motion of her neck. Her trachea was tender upon palpation but without jugular venous distension or lymphadenopathy. The cardiac examination was significant for tachycardia with a regular rhythm and without murmurs, rubs, or gallops; the pulmonary examination was normal except for transmitted upper airway sounds. The patient’s abdominal, dermatological, and neurological examinations were all normal.

Based on the examination findings, the differential diagnosis included allergic reaction, angioedema, epiglottitis, and retropharyngeal abscess. An intravenous (IV) line was placed and blood was drawn for laboratory evaluation, which included a complete blood count, basic metabolic panel (BMP), and a quantitative pregnancy test. Given the patient’s history, the emergency physician (EP) was most concerned for an allergic reaction, and administered epinephrine 0.5 mg (1:1,000) intramuscularly (IM) in the mid-anterolateral thigh, in addition to methylprednisolone, 125 mg; diphenhydramine, 25 mg; and famotidine, 20 mg IV.

A portable soft-tissue lateral radiograph of the neck was obtained. Radiology services interpreted the film as showing “prominent prevertebral soft tissues and epiglottis.

Discussion

While the incidence of pediatric epiglottitis has decreased since the introduction of the Haemophilus influenzae type b (Hib) vaccine in 1985, adult epiglottitis continues to represent a potentially life-threatening condition whose incidence has remained constant over the past several decades.^1,2 The incidence of supraglottitis in adults is now 2.5 times greater than the incidence in children.^3,4

Several important differences exist in the presentation and management of adults who present with inflammation of the epiglottis as compared to children. Children commonly present with an acute onset of symptoms, and due to their smaller and more pliant airway anatomy, they often experience stridor and respiratory distress.^3,5 The inflammation in children is typically confined to the epiglottis and aryepiglottic folds, while in adults the inflammation can affect not only the epiglottis, but also supraglottic structures such as the pharynx, uvula, and aryepiglottic folds. For this reason, in adults the condition is often referred to as “supraglottitis.”^2,6 Adults with supraglottitis most likely present in their 30s, 40s, and 50s, while children present between the ages of 2 and 5 years old.^1,3,7 In adults, men more commonly present with supraglottitis than women.^1,2 Cigarette smokers and patients with hypertension, diabetes mellitus (DM), chronic obstructive pulmonary disease, or human immunodeficiency virus/AIDS are at increased risk for supraglottitis.^3,4 The mortality rate for adults with supraglottitis ranges from 1.2% to 7.1%.³

Etiology

Prior to the use of the Hib vaccine, Hib was the most common cause of epiglottitis, and remains so for children.¹ Currently, the most common cause of supraglottitis in adults is Group A beta-hemolytic Streptococci.² Other etiologies include other bacteria (Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas species, Klebsiella pneumoniae, Pasteurella multocida, Neisseria species), viruses (herpes simplex, varicella, parainfluenza), trauma, and thermal injuries.^1,4,5,8

Signs and Symptoms

Throat pain, dysphagia, odynophagia, and muffled voice are common complaints of adults presenting to the ED with supraglottitis.^2,7 Fever is usually, but not always, present; the complaint of cough, however, is rare.^2,3,4 Other less frequent complaints include hoarseness and drooling. Adults can also present with cervical lymphadenopathy, anterior neck tenderness, and cellulitis of the neck and chest.^2,4 In general, the more severe cases will progress rapidly over a few hours. Due to the larger anatomy in adults, they are more likely than children to experience a gradual progression of symptoms, and supraglottitis will be missed on the initial presentation in up to 50% of adults.^3,4 Stridor or respiratory compromise does occur in a minority of adult patients with supraglottitis. The need for artificial airway support (ie, endotracheal intubation, cricothyroidotomy) in adults ranges from 6.6% to 16%.^9,10

Making the Diagnosis

The gold standard for diagnosing supraglottitis is direct laryngoscopy.^3,4 This point is emphasized in our case report, since the CT scan was concerning for a retropharyngeal abscess, and not supraglottitis. The examination of the oropharynx is generally safer and better tolerated in adults compared to pediatric patients, since airway compromise is much less likely. On occasion, inflammation, erythema, and edema of the epiglottis, aryepiglottic folds, or arytenoid cartilages can be observed.⁵ More commonly, the supraglottic structures are not visualized, and the posterior oropharynx appears relatively normal. This should serve as a clue for possible supraglottitis.

In suspected cases of adult supraglottitis without emergent airway compromise, lateral soft-tissue radiographs can be obtained to look for the “thumb sign,” indicating a swollen epiglottis. In adult supraglottitis, the width of the epiglottis is usually greater than 8 mm.¹¹ Other abnormal radiographic findings include arytenoid and aryepiglottic fold enlargement, thinning of the airway, and an increase in size of the prevertebral space. Plain film sensitivity rates range from 38% to 98%.

Complete blood count and throat cultures are not particularly helpful in adult cases. Blood cultures, while only about 30% sensitive in adults, should be considered as supraglottitis can result in secondary infection in the central nervous system, lungs, and surrounding structures.^3,5

If available, otolaryngology services should be consulted to evaluate the airway, and IV antibiotics, such as a third-generation cephalosporin (eg, ceftriaxone, cefotaxime), should be initiated to include coverage of Hib.³ If methicillin-resistant S aureus is a concern, vancomycin should be added. Clindamycin or metronidazole should also be given if anaerobes are suspected.^4,7 The location for performing the nasopharyngeal laryngoscopy varies, depending on the patient’s age (ie, pediatric vs adult), severity of symptoms, presence of airway compromise, and local practice and custom.

Advanced imaging studies (CT scan or magnetic resonance imaging) can help identify the presence of an abscess and delineate the extent of the infection, but are not indicated in the early diagnosis and management of suspected adult supraglottitis.⁴ As our case demonstrates, CT is neither highly sensitive nor specific for the diagnosis of epiglottitis. The role of ultrasound in the evaluation of suspected epiglottitis is still being developed. One recent study compared 15 healthy volunteers with 15 patients diagnosed with epiglottitis by an otolaryngologist using laryngoscopy.¹² A statistically significant difference was observed in the anteroposterior diameter of the epiglottis at the midpoint and both lateral edges between the study subjects and healthy volunteers.¹² While there was overlap in the ranges for the midpoint, there was no overlap in both lateral edges between the two groups.¹²

Treatment

The vast majority of adult cases of supraglottitis are managed medically without airway intervention. Patients presenting with a rapid onset of symptoms and in respiratory distress or with stridor, drooling, or cyanosis, should be managed with early airway intervention. The use of corticosteroids is controversial, and has not been proven beneficial in any prospective trials.^1-4,6,7,13

Admission to a critical care unit is indicated initially, even in patients who are not intubated, as they can experience delayed airway compromise with progression of the infection and edema.¹³

Complications

Abscess formation is a serious complication of supraglottitis, is present in up to 30% of cases, and is more likely to be seen in adults than in children.¹³ Since the adult larynx and surrounding tissues are larger than in children, often the infection is present longer, which allows for an abscess to develop. The risk of abscess formation is increased in patients with DM or those in whom a foreign body is present.

Numerous organisms have been isolated from supraglottic abscesses in adults, and in addition to incision and drainage, antibiotics covering both gram-positive organisms and anaerobes should be initiated.⁵ The presence of a supraglottic abscess increases the need for emergent intubation.¹³ In addition, a supraglottic abscess increases the mortality rate to 30%.³ Other complications from supraglottitis include mediastinitis, cervical adenitis, meningitis, and pneumonia.^4,5

Conclusion

While the incidence of epiglottitis in the pediatric patient population has fallen, the incidence in adults remains relatively stable. Clinicians should consider supraglottitis in the differential diagnosis of adults presenting with severe sore throat, dysphagia, or stridor. While airway compromise in adults is uncommon, it does occur. Soft-tissue lateral neck radiographs can help make the diagnosis, but the gold standard remains laryngoscopy. All patients should be started on IV antibiotics and admitted to the ICU initially for airway watch.

Case

A 25-year-old college student presented to the ED following a near-syncopal episode. The patient stated he had felt lightheaded and had fallen to his knees immediately after taking a shower earlier that morning, but did not experience any loss of consciousness or injury. He denied a history of syncope or any recent trauma or fatigue. A review of the patient’s systems was negative. His medical history was remarkable for irritable bowel syndrome; he had no surgical history. Regarding his social history, he admitted to occasional alcohol use but denied any tobacco or illicit drug use. He was not on any current prescription or over-the-counter medications and denied any allergies.

The patient’s initial vital signs at presentation were: blood pressure, 112/58 mm Hg; heart rate, 86 beats/min; temperature, 97.9°F; and respiratory rate, 18 breaths/min. Oxygen saturation was 100% on room air. The patient reported pain in his left shoulder, epigastric region, and right flank. He rated his pain as a “4” on a 0-to-10 pain scale.

On physical examination, the patient was alert and oriented; he was thin and had mild pallor. His head, eyes, ears, nose, and throat; cardiac; pulmonary; and neurological examinations were normal. The abdominal examination revealed a soft, minimally tender epigastrium but with normal bowel sounds. Initial laboratory studies were remarkable for low hemoglobin (Hgb; 12.0 g/dL) and elevated aspartate transaminase (105 U/L), alanine aminotransferase (168 U/L), total bilirubin (1.6 mg/dL), and glucose (179 mg/dL) levels. The patient’s troponin I and lipase levels were within normal range. An electrocardiogram was unremarkable.

Given the patient’s elevated hepatic enzymes, right upper quadrant ultrasound was obtained, which demonstrated a normal gallbladder, a moderate amount of complicated free fluid (with hyper-echoic densities suggestive of coagulated blood) in all four quadrants, and splenomegaly measuring 13.7 cm (Figure 1a and 1b).

Positive:

• Epstein-Barr virus (EBV)

• Viral capsid antigen (VCA) immuno­globulin G

• VCA immunoglobulin M

Negative:

• Mononuclear spot test
• Human immunodeficiency virus
• Hepatitis B and C
• Antinuclear antibodies
• Venereal disease research laboratory test

The rest of the patient’s recovery was uneventful, and he was discharged home in stable condition on hospital day 3.

Discussion

Although the spleen is the most common intra-abdominal organ that can rupture with blunt abdominal trauma, splenic rupture in the absence of trauma is very rare. Nontraumatic splenic rupture (NSR) has been associated with pathological and nonpathological spleens.^1,2 A systemic review of NSRs showed that 7% of the 845 patients in the review had completely normal spleens; the remaining 93% had some form of splenic pathology.¹

Etiology

The top three causes of splenic enlargement associated with NSR include hematologic malignancies, viral infections, and inflammation.^1,2 Although viruses, such as EBV and cytomegalovirus, represent almost 15% of the pathological causes of NSR, it is not uncommon for a patient to have multiple pathological processes present.¹ Our patient’s enlarged spleen was due to acute infectious mononucleosis.

Signs and Symptoms

Diagnosing NSR can be challenging and it is often missed or discovered incidentally during evaluation (as was initially the case with our patient).³ Several signs and symptoms present in our patient were red herrings that warranted closer analysis. The patient’s complaint of left shoulder pain suggested left hemidiaphragm irritation from the NSR. Furthermore, our patient’s near-syncopal episode was possibly due to acute vagal simulation from the initial contact of blood with the peritoneal cavity.⁴ The maximal vagal stimulus was likely transient, as our patient returned to baseline after a brief near-syncopal episode.

As illustrated in our case, though tachycardia is common in splenic rupture, not all patients present with this sign. The absence of tachycardia in our patient can be explained by the elevation of his baseline enteric vagal tone due to the continued presence of blood in the peritoneum.⁵ There are also other factors associated with the absence of tachycardia. For example, a well-conditioned athlete presenting with states of shock due to splenic rupture may not show signs of tachycardia.⁶

San Francisco Syncope Rule

The San Francisco Syncope Rule (SFSR) is a clinical decision-making risk-stratification tool used to determine outcomes and disposition of ED patients presenting with syncope.⁷ It is important to note that if we had used a straightforward application of the SFSR upon our patient’s initial presentation, the results would have been negative, suggesting he was not at risk for short-term serious outcomes.⁷

Imaging Studies

As demonstrated in our patient, a quick point-of-care (POC) bedside ultrasound scan can reveal the presence of free fluid in the abdomen to help with the diagnosis. On ultrasound, the presence of free fluid in the right upper quadrant is more commonly found in the hepatorenal recess, whereas in the left upper quadrant free fluid is seen sub-diaphragmatic/suprasplenic first before fluid is seen in the splenorenal recess. Bedside ultrasound can accurately detect as little as 100 mL of free fluid in the abdominal cavity, with a 90% sensitivity and 99% specificity.⁸

An ultrasound is highly sensitive as a preliminary screening tool to identify the presence of free intraperitoneal fluid and has some limited utility in identifying any disruption in the splenic echotexture that may suggest a laceration or hematoma. Ultrasound, however, has poor specificity in identifying solid organ injuries.⁹

Computed tomography scanning is the imaging modality of choice for assessing splenic injuries, and should be obtained to confirm the presence of a solid organ injury, as well as to grade the degree of injury and thereby determine the need for surgical intervention.¹⁰ It is worth noting that in a hemodynamically unstable patient, exploratory laparotomy may be embarked upon without a CT scan and positive free fluid on ultrasound.

Splenic Injury Scale

Splenic injury is classified on a scale of 1 (mild injury) to 5 (severe injury) (Table).¹¹

Conclusion

This case illustrates an uncommon presentation of NSR and underscores the importance of considering NSR in the differential diagnoses of patients presenting with abdominal pain—a sign with such a broad differential that NSR could easily be missed during evaluation. Based on its high sensitivity and specificity in detecting the presence of free fluid in the abdominal cavity, POC ultrasound imaging should be used to evaluate patients presenting with abdominal pain and syncopal or near-syncopal symptoms. This case further demonstrates that the absence of tachycardia or signs of shock should not rule out NSR.

Case

A 25-year-old college student presented to the ED following a near-syncopal episode. The patient stated he had felt lightheaded and had fallen to his knees immediately after taking a shower earlier that morning, but did not experience any loss of consciousness or injury. He denied a history of syncope or any recent trauma or fatigue. A review of the patient’s systems was negative. His medical history was remarkable for irritable bowel syndrome; he had no surgical history. Regarding his social history, he admitted to occasional alcohol use but denied any tobacco or illicit drug use. He was not on any current prescription or over-the-counter medications and denied any allergies.

The patient’s initial vital signs at presentation were: blood pressure, 112/58 mm Hg; heart rate, 86 beats/min; temperature, 97.9°F; and respiratory rate, 18 breaths/min. Oxygen saturation was 100% on room air. The patient reported pain in his left shoulder, epigastric region, and right flank. He rated his pain as a “4” on a 0-to-10 pain scale.

On physical examination, the patient was alert and oriented; he was thin and had mild pallor. His head, eyes, ears, nose, and throat; cardiac; pulmonary; and neurological examinations were normal. The abdominal examination revealed a soft, minimally tender epigastrium but with normal bowel sounds. Initial laboratory studies were remarkable for low hemoglobin (Hgb; 12.0 g/dL) and elevated aspartate transaminase (105 U/L), alanine aminotransferase (168 U/L), total bilirubin (1.6 mg/dL), and glucose (179 mg/dL) levels. The patient’s troponin I and lipase levels were within normal range. An electrocardiogram was unremarkable.

Given the patient’s elevated hepatic enzymes, right upper quadrant ultrasound was obtained, which demonstrated a normal gallbladder, a moderate amount of complicated free fluid (with hyper-echoic densities suggestive of coagulated blood) in all four quadrants, and splenomegaly measuring 13.7 cm (Figure 1a and 1b).

Positive:

• Epstein-Barr virus (EBV)

• Viral capsid antigen (VCA) immuno­globulin G

• VCA immunoglobulin M

Negative:

• Mononuclear spot test
• Human immunodeficiency virus
• Hepatitis B and C
• Antinuclear antibodies
• Venereal disease research laboratory test

The rest of the patient’s recovery was uneventful, and he was discharged home in stable condition on hospital day 3.

Discussion

Although the spleen is the most common intra-abdominal organ that can rupture with blunt abdominal trauma, splenic rupture in the absence of trauma is very rare. Nontraumatic splenic rupture (NSR) has been associated with pathological and nonpathological spleens.^1,2 A systemic review of NSRs showed that 7% of the 845 patients in the review had completely normal spleens; the remaining 93% had some form of splenic pathology.¹

Etiology

The top three causes of splenic enlargement associated with NSR include hematologic malignancies, viral infections, and inflammation.^1,2 Although viruses, such as EBV and cytomegalovirus, represent almost 15% of the pathological causes of NSR, it is not uncommon for a patient to have multiple pathological processes present.¹ Our patient’s enlarged spleen was due to acute infectious mononucleosis.

Signs and Symptoms

Diagnosing NSR can be challenging and it is often missed or discovered incidentally during evaluation (as was initially the case with our patient).³ Several signs and symptoms present in our patient were red herrings that warranted closer analysis. The patient’s complaint of left shoulder pain suggested left hemidiaphragm irritation from the NSR. Furthermore, our patient’s near-syncopal episode was possibly due to acute vagal simulation from the initial contact of blood with the peritoneal cavity.⁴ The maximal vagal stimulus was likely transient, as our patient returned to baseline after a brief near-syncopal episode.

As illustrated in our case, though tachycardia is common in splenic rupture, not all patients present with this sign. The absence of tachycardia in our patient can be explained by the elevation of his baseline enteric vagal tone due to the continued presence of blood in the peritoneum.⁵ There are also other factors associated with the absence of tachycardia. For example, a well-conditioned athlete presenting with states of shock due to splenic rupture may not show signs of tachycardia.⁶

San Francisco Syncope Rule

The San Francisco Syncope Rule (SFSR) is a clinical decision-making risk-stratification tool used to determine outcomes and disposition of ED patients presenting with syncope.⁷ It is important to note that if we had used a straightforward application of the SFSR upon our patient’s initial presentation, the results would have been negative, suggesting he was not at risk for short-term serious outcomes.⁷

Imaging Studies

As demonstrated in our patient, a quick point-of-care (POC) bedside ultrasound scan can reveal the presence of free fluid in the abdomen to help with the diagnosis. On ultrasound, the presence of free fluid in the right upper quadrant is more commonly found in the hepatorenal recess, whereas in the left upper quadrant free fluid is seen sub-diaphragmatic/suprasplenic first before fluid is seen in the splenorenal recess. Bedside ultrasound can accurately detect as little as 100 mL of free fluid in the abdominal cavity, with a 90% sensitivity and 99% specificity.⁸

An ultrasound is highly sensitive as a preliminary screening tool to identify the presence of free intraperitoneal fluid and has some limited utility in identifying any disruption in the splenic echotexture that may suggest a laceration or hematoma. Ultrasound, however, has poor specificity in identifying solid organ injuries.⁹

Computed tomography scanning is the imaging modality of choice for assessing splenic injuries, and should be obtained to confirm the presence of a solid organ injury, as well as to grade the degree of injury and thereby determine the need for surgical intervention.¹⁰ It is worth noting that in a hemodynamically unstable patient, exploratory laparotomy may be embarked upon without a CT scan and positive free fluid on ultrasound.

Splenic Injury Scale

Splenic injury is classified on a scale of 1 (mild injury) to 5 (severe injury) (Table).¹¹

Conclusion

This case illustrates an uncommon presentation of NSR and underscores the importance of considering NSR in the differential diagnoses of patients presenting with abdominal pain—a sign with such a broad differential that NSR could easily be missed during evaluation. Based on its high sensitivity and specificity in detecting the presence of free fluid in the abdominal cavity, POC ultrasound imaging should be used to evaluate patients presenting with abdominal pain and syncopal or near-syncopal symptoms. This case further demonstrates that the absence of tachycardia or signs of shock should not rule out NSR.

Case

A 25-year-old college student presented to the ED following a near-syncopal episode. The patient stated he had felt lightheaded and had fallen to his knees immediately after taking a shower earlier that morning, but did not experience any loss of consciousness or injury. He denied a history of syncope or any recent trauma or fatigue. A review of the patient’s systems was negative. His medical history was remarkable for irritable bowel syndrome; he had no surgical history. Regarding his social history, he admitted to occasional alcohol use but denied any tobacco or illicit drug use. He was not on any current prescription or over-the-counter medications and denied any allergies.

The patient’s initial vital signs at presentation were: blood pressure, 112/58 mm Hg; heart rate, 86 beats/min; temperature, 97.9°F; and respiratory rate, 18 breaths/min. Oxygen saturation was 100% on room air. The patient reported pain in his left shoulder, epigastric region, and right flank. He rated his pain as a “4” on a 0-to-10 pain scale.

On physical examination, the patient was alert and oriented; he was thin and had mild pallor. His head, eyes, ears, nose, and throat; cardiac; pulmonary; and neurological examinations were normal. The abdominal examination revealed a soft, minimally tender epigastrium but with normal bowel sounds. Initial laboratory studies were remarkable for low hemoglobin (Hgb; 12.0 g/dL) and elevated aspartate transaminase (105 U/L), alanine aminotransferase (168 U/L), total bilirubin (1.6 mg/dL), and glucose (179 mg/dL) levels. The patient’s troponin I and lipase levels were within normal range. An electrocardiogram was unremarkable.

Given the patient’s elevated hepatic enzymes, right upper quadrant ultrasound was obtained, which demonstrated a normal gallbladder, a moderate amount of complicated free fluid (with hyper-echoic densities suggestive of coagulated blood) in all four quadrants, and splenomegaly measuring 13.7 cm (Figure 1a and 1b).

Positive:

• Epstein-Barr virus (EBV)

• Viral capsid antigen (VCA) immuno­globulin G

• VCA immunoglobulin M

Negative:

• Mononuclear spot test
• Human immunodeficiency virus
• Hepatitis B and C
• Antinuclear antibodies
• Venereal disease research laboratory test

The rest of the patient’s recovery was uneventful, and he was discharged home in stable condition on hospital day 3.

Discussion

Although the spleen is the most common intra-abdominal organ that can rupture with blunt abdominal trauma, splenic rupture in the absence of trauma is very rare. Nontraumatic splenic rupture (NSR) has been associated with pathological and nonpathological spleens.^1,2 A systemic review of NSRs showed that 7% of the 845 patients in the review had completely normal spleens; the remaining 93% had some form of splenic pathology.¹

Etiology

The top three causes of splenic enlargement associated with NSR include hematologic malignancies, viral infections, and inflammation.^1,2 Although viruses, such as EBV and cytomegalovirus, represent almost 15% of the pathological causes of NSR, it is not uncommon for a patient to have multiple pathological processes present.¹ Our patient’s enlarged spleen was due to acute infectious mononucleosis.

Signs and Symptoms

Diagnosing NSR can be challenging and it is often missed or discovered incidentally during evaluation (as was initially the case with our patient).³ Several signs and symptoms present in our patient were red herrings that warranted closer analysis. The patient’s complaint of left shoulder pain suggested left hemidiaphragm irritation from the NSR. Furthermore, our patient’s near-syncopal episode was possibly due to acute vagal simulation from the initial contact of blood with the peritoneal cavity.⁴ The maximal vagal stimulus was likely transient, as our patient returned to baseline after a brief near-syncopal episode.

As illustrated in our case, though tachycardia is common in splenic rupture, not all patients present with this sign. The absence of tachycardia in our patient can be explained by the elevation of his baseline enteric vagal tone due to the continued presence of blood in the peritoneum.⁵ There are also other factors associated with the absence of tachycardia. For example, a well-conditioned athlete presenting with states of shock due to splenic rupture may not show signs of tachycardia.⁶

San Francisco Syncope Rule

The San Francisco Syncope Rule (SFSR) is a clinical decision-making risk-stratification tool used to determine outcomes and disposition of ED patients presenting with syncope.⁷ It is important to note that if we had used a straightforward application of the SFSR upon our patient’s initial presentation, the results would have been negative, suggesting he was not at risk for short-term serious outcomes.⁷

Imaging Studies

As demonstrated in our patient, a quick point-of-care (POC) bedside ultrasound scan can reveal the presence of free fluid in the abdomen to help with the diagnosis. On ultrasound, the presence of free fluid in the right upper quadrant is more commonly found in the hepatorenal recess, whereas in the left upper quadrant free fluid is seen sub-diaphragmatic/suprasplenic first before fluid is seen in the splenorenal recess. Bedside ultrasound can accurately detect as little as 100 mL of free fluid in the abdominal cavity, with a 90% sensitivity and 99% specificity.⁸

An ultrasound is highly sensitive as a preliminary screening tool to identify the presence of free intraperitoneal fluid and has some limited utility in identifying any disruption in the splenic echotexture that may suggest a laceration or hematoma. Ultrasound, however, has poor specificity in identifying solid organ injuries.⁹

Computed tomography scanning is the imaging modality of choice for assessing splenic injuries, and should be obtained to confirm the presence of a solid organ injury, as well as to grade the degree of injury and thereby determine the need for surgical intervention.¹⁰ It is worth noting that in a hemodynamically unstable patient, exploratory laparotomy may be embarked upon without a CT scan and positive free fluid on ultrasound.

Splenic Injury Scale

Splenic injury is classified on a scale of 1 (mild injury) to 5 (severe injury) (Table).¹¹

Conclusion

This case illustrates an uncommon presentation of NSR and underscores the importance of considering NSR in the differential diagnoses of patients presenting with abdominal pain—a sign with such a broad differential that NSR could easily be missed during evaluation. Based on its high sensitivity and specificity in detecting the presence of free fluid in the abdominal cavity, POC ultrasound imaging should be used to evaluate patients presenting with abdominal pain and syncopal or near-syncopal symptoms. This case further demonstrates that the absence of tachycardia or signs of shock should not rule out NSR.

Months of extremely high temperatures throughout the United States made the summer of 2016 one of the hottest summers on record. The summer may also be remembered for the excessive amounts of hot air generated in the run-up to the 2016 presidential election. But most oppressive of all has been the failure of Congress to appropriate funds for Zika virus research, prevention, and treatment before it recessed for vacation.

Emergency physicians (EPs) in the United States are already dealing with frightened, symptomatic patients who may have been exposed to the Zika, dengue, or chikungunya viruses, transmitted by the bite of the Aedes aegypti mosquito. In the First EDition section of this issue, dermatologist Iris Z. Ahronowitz, MD, describes some of the similarities in the acute clinical presentations of those infections (see page 438). But among this group of related viruses, only Zika has been positively linked to microcephaly and severely underdeveloped, damaged brains in babies born to women who are infected during pregnancy. An increasing number of newborn babies severely affected by Zika virus in utero began appearing in South America in late 2015. By summer’s end (September 21, 2016), the Centers for Disease Control and Prevention reports of Zika virus disease in the United States included over 3,300 travel-related cases, 43 locally acquired mosquito-borne cases, 28 sexually transmitted cases, and eight cases of Guillain-Barré syndrome (http://www.cdc.gov/zika/geo/united-states.html). Most importantly, as of September 15, 2016, there have been 20 live-born infants with birth defects and five pregnancy losses with birth defects—numbers that do not reflect the outcomes of ongoing pregnancies.

The life expectancy of babies severely affected by Zika virus and the nature and extent of disability in less physically affected babies are presently unknown. But according to The Washington Post (http://wapo.st/29Y5CnR), estimates of the cost of caring for a severely affected Zika baby through adulthood run as high as $10 million or more, and as high a total price as we will pay for the congressional intransigence this summer, such cost estimates do not even consider the terrible human suffering these babies will experience or the anguish their parents may have for the rest of their lives.

Emergency physicians are all too familiar with the emotional and behavioral problems that complicate our efforts to manage acute medical problems of children and adults born with autism or Down syndrome when they present to the ED. Most such congenital illnesses are not preventable, but when one potentially is, delaying needed resources because of partisan politics is unconscionable.

By summer’s end, as the last of leftover Ebola dollars were being spent on Zika-related programs, Democrats and Republicans finally appeared to be reaching a consensus to provide $1.1 billion of the $1.9 billion originally requested by the President long before the long hot summer began. This sudden agreement may be driven by the importance both parties place on winning the Florida vote in the upcoming election. But whatever the reason, Zika funding now will help prevent untold hardships and suffering in the years to come. In the meantime, EPs will continue to evaluate, diagnose, counsel, and, hopefully someday soon, be able to treat all who come to our EDs with Zika infection. 

Months of extremely high temperatures throughout the United States made the summer of 2016 one of the hottest summers on record. The summer may also be remembered for the excessive amounts of hot air generated in the run-up to the 2016 presidential election. But most oppressive of all has been the failure of Congress to appropriate funds for Zika virus research, prevention, and treatment before it recessed for vacation.

Emergency physicians (EPs) in the United States are already dealing with frightened, symptomatic patients who may have been exposed to the Zika, dengue, or chikungunya viruses, transmitted by the bite of the Aedes aegypti mosquito. In the First EDition section of this issue, dermatologist Iris Z. Ahronowitz, MD, describes some of the similarities in the acute clinical presentations of those infections (see page 438). But among this group of related viruses, only Zika has been positively linked to microcephaly and severely underdeveloped, damaged brains in babies born to women who are infected during pregnancy. An increasing number of newborn babies severely affected by Zika virus in utero began appearing in South America in late 2015. By summer’s end (September 21, 2016), the Centers for Disease Control and Prevention reports of Zika virus disease in the United States included over 3,300 travel-related cases, 43 locally acquired mosquito-borne cases, 28 sexually transmitted cases, and eight cases of Guillain-Barré syndrome (http://www.cdc.gov/zika/geo/united-states.html). Most importantly, as of September 15, 2016, there have been 20 live-born infants with birth defects and five pregnancy losses with birth defects—numbers that do not reflect the outcomes of ongoing pregnancies.

The life expectancy of babies severely affected by Zika virus and the nature and extent of disability in less physically affected babies are presently unknown. But according to The Washington Post (http://wapo.st/29Y5CnR), estimates of the cost of caring for a severely affected Zika baby through adulthood run as high as $10 million or more, and as high a total price as we will pay for the congressional intransigence this summer, such cost estimates do not even consider the terrible human suffering these babies will experience or the anguish their parents may have for the rest of their lives.

Emergency physicians are all too familiar with the emotional and behavioral problems that complicate our efforts to manage acute medical problems of children and adults born with autism or Down syndrome when they present to the ED. Most such congenital illnesses are not preventable, but when one potentially is, delaying needed resources because of partisan politics is unconscionable.

By summer’s end, as the last of leftover Ebola dollars were being spent on Zika-related programs, Democrats and Republicans finally appeared to be reaching a consensus to provide $1.1 billion of the $1.9 billion originally requested by the President long before the long hot summer began. This sudden agreement may be driven by the importance both parties place on winning the Florida vote in the upcoming election. But whatever the reason, Zika funding now will help prevent untold hardships and suffering in the years to come. In the meantime, EPs will continue to evaluate, diagnose, counsel, and, hopefully someday soon, be able to treat all who come to our EDs with Zika infection. 

Months of extremely high temperatures throughout the United States made the summer of 2016 one of the hottest summers on record. The summer may also be remembered for the excessive amounts of hot air generated in the run-up to the 2016 presidential election. But most oppressive of all has been the failure of Congress to appropriate funds for Zika virus research, prevention, and treatment before it recessed for vacation.

Emergency physicians (EPs) in the United States are already dealing with frightened, symptomatic patients who may have been exposed to the Zika, dengue, or chikungunya viruses, transmitted by the bite of the Aedes aegypti mosquito. In the First EDition section of this issue, dermatologist Iris Z. Ahronowitz, MD, describes some of the similarities in the acute clinical presentations of those infections (see page 438). But among this group of related viruses, only Zika has been positively linked to microcephaly and severely underdeveloped, damaged brains in babies born to women who are infected during pregnancy. An increasing number of newborn babies severely affected by Zika virus in utero began appearing in South America in late 2015. By summer’s end (September 21, 2016), the Centers for Disease Control and Prevention reports of Zika virus disease in the United States included over 3,300 travel-related cases, 43 locally acquired mosquito-borne cases, 28 sexually transmitted cases, and eight cases of Guillain-Barré syndrome (http://www.cdc.gov/zika/geo/united-states.html). Most importantly, as of September 15, 2016, there have been 20 live-born infants with birth defects and five pregnancy losses with birth defects—numbers that do not reflect the outcomes of ongoing pregnancies.

The life expectancy of babies severely affected by Zika virus and the nature and extent of disability in less physically affected babies are presently unknown. But according to The Washington Post (http://wapo.st/29Y5CnR), estimates of the cost of caring for a severely affected Zika baby through adulthood run as high as $10 million or more, and as high a total price as we will pay for the congressional intransigence this summer, such cost estimates do not even consider the terrible human suffering these babies will experience or the anguish their parents may have for the rest of their lives.

Emergency physicians are all too familiar with the emotional and behavioral problems that complicate our efforts to manage acute medical problems of children and adults born with autism or Down syndrome when they present to the ED. Most such congenital illnesses are not preventable, but when one potentially is, delaying needed resources because of partisan politics is unconscionable.

By summer’s end, as the last of leftover Ebola dollars were being spent on Zika-related programs, Democrats and Republicans finally appeared to be reaching a consensus to provide $1.1 billion of the $1.9 billion originally requested by the President long before the long hot summer began. This sudden agreement may be driven by the importance both parties place on winning the Florida vote in the upcoming election. But whatever the reason, Zika funding now will help prevent untold hardships and suffering in the years to come. In the meantime, EPs will continue to evaluate, diagnose, counsel, and, hopefully someday soon, be able to treat all who come to our EDs with Zika infection. 

End-stage osteoarthritis of the hip is a debilitating disease that is reliably treated with total hip arthroplasty (THA).¹ Up to 35% of patients who undergo THA eventually require contralateral THA.^2,3 In patients who present with advanced bilateral disease and undergo unilateral THA, the risk of ultimately requiring a contralateral procedure is as high as 97%.^3-6 In patients with bilateral hip disease, function is not fully optimized until both hips have been replaced, particularly in the setting of fixed flexion contractures.^7-9 Naturally, there has been some interest in simultaneous bilateral THAs for select patients.

The potential benefits of bilateral THAs over staged procedures include faster overall rehabilitation, exposure to a single anesthetic, reduced hospital length of stay (LOS), and cost savings.^10-12 However, opinion on recommending bilateral THAs is mixed. Although bilateral procedures historically have been fraught with perioperative complications,^13,14 advances in surgical and anesthetic techniques have led to improved outcomes.¹⁵ Whether surgical approach is a factor in these outcomes is unclear.

The popularity of the direct anterior (DA) approach for THA has increased in recent years.¹⁶ Although the relative advantages of various approaches remain in debate, one potential benefit of the DA approach is supine positioning, which allows simultaneous bilateral THAs to be performed without the need for repositioning before proceeding with the contralateral side. However, simultaneous bilateral THAs performed through the DA approach and those performed through other surgical approaches are lacking in comparative outcomes data.¹⁷In this study, we evaluated operative times, transfusion requirements, hospital discharge data, and 90-day complication rates in patients who had simultaneous bilateral THAs through either the DA approach or the posterior approach.

Methods

Study Design

This single-center study was conducted at the Mayo Clinic in Rochester, Minnesota. After obtaining approval from our Institutional Review Board, we performed a retrospective cohort analysis. We used our institution’s total joint registry to identify all patients who underwent simultaneous bilateral THAs through either the DA approach or the posterior approach. The first bilateral THAs to use the DA approach at our institution were performed in 2012. To ensure that the DA and posterior groups’ perioperative management would be similar, we included only cases performed between 2012 and 2014.

There were 19 patients in the DA group and 21 in the posterior group. The groups were similar in mean age (54 vs 54 years; P = .90), sex (73% vs 57% males; P = .33), body mass index (BMI; 25 vs 28 kg/m²; P = .38), preoperative hemoglobin level (14.3 vs 14.0 g/dL; P = .37), preoperative diagnosis (71.1% vs 78.6% degenerative joint disease; P = .75), and American Society of Anesthesiologists (ASA) score (1.9 vs 2.0; P = .63) (Table 1).

Patient Care

All cases were performed by 1 of 3 dedicated arthroplasty surgeons (Dr. Taunton, Dr. Sierra, Dr. Trousdale). Dr. Taunton exclusively uses the DA approach, and Dr. Sierra and Dr. Trousdale exclusively use the posterior approach. Patients in both groups received preoperative medical clearance and attended the same preoperative education class.

Patients in the DA group were positioned supine on an orthopedic table that allows hyperextension and adduction of the operative leg. Both hips were prepared and draped simultaneously. The most symptomatic hip was operated on first, with a sterile drape covering the contralateral hip. Between hips, fluoroscopy was moved to the other side of the operative suite, but no changes in positioning or preparation were necessary. A deep drain was placed on each side, and then was removed the morning of postoperative day 1. The same set of instruments was used on both sides.

Patients in the posterior group were positioned lateral on a regular operative table with hip rests. The most symptomatic hip was operated on first. After wound closure and dressing application, the patient was flipped to allow access to the contralateral hip and was prepared and draped again. The same instruments were used on each side. Drains were not used.

All patients received the same comprehensive multimodal pain management, which combined general and epidural anesthesia (remaining in place until postoperative day 2) and included an oral pain regimen of scheduled acetaminophen and as-needed tramadol and oxycodone. In all cases, intraoperative blood salvage and intravenous tranexamic acid (1 g at time of incision on first hip, 1 g at wound closure on second hip) were used. Preoperative autologous blood donation was not used. For deep vein thrombosis prophylaxis, patients were treated with bilateral sequential compression devices while hospitalized, but chemoprophylaxis was different between groups. Patients in the DA group received prophylactic low-molecular-weight heparin for 10 days, followed by twice-daily aspirin (325 mg) for 4 weeks. Patients in the posterior group received warfarin (goal international normalized ratio, 1.7-2.2) for 3 weeks, followed by twice-daily aspirin (325 mg) for 3 weeks. The decision to transfuse allogenic red blood cells was made by the treating surgeon, based on standardized hospital protocols, wherein patients are transfused for hemoglobin levels under 7.0 g/dL, or for hemoglobin levels less than 8.0 g/dL in the presence of persistent symptoms. All patients received care on an orthopedic specialty floor and were assisted by the same physical therapists. Discharge disposition was coordinated with the same group of social workers.

Two to 3 months after surgery, patients returned for routine examination and radiographs. All patients were followed up for at least 90 days.

Statistical Analysis

All outcomes were analyzed with appropriate summary statistics. Chi-square tests or logistic regression analyses (for categorical outcomes) were used to compare baseline covariates with perioperative outcomes, and 2-sample tests or Wilcoxon rank-sum tests were used to compare outcomes measured on a continuous scale. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated as appropriate. Operative time was calculated by adding time from incision to wound closure for both hips (room turnover time between hips was not included). Anesthesia time was defined as total time patients were in the operating room. All statistical tests were 2-sided, and the threshold for statistical significance was set at α = 0.05.

Results

Compared with patients who underwent simultaneous bilateral THAs through the posterior approach, patients who underwent simultaneous bilateral THAs through the DA approach had longer mean operative times (153 vs 106 min; P < .001) and anesthesia times (257 vs 221 min; P = .007). The 2 groups’ hospital stays were similar in length (3.1 vs 3.5 days; P = .31), but patients in the DA group were more likely to be discharged home (100.0% vs 71.4%; P = .02) (Table 2).

Patients in the DA group were more likely to have sufficient intraoperative blood salvage for autologous transfusion (89.5% vs 57.1%; OR, 6.4; 95% CI, 1.16-34.94; P = .03) (Table 3) and received more mean units of salvaged autologous blood (1.4 vs 0.5; P = .003) (Table 2). Allogenic blood was not given to any patients in the DA group, but 3 patients in the posterior group (14.3%) required allogenic blood transfusion (P = .23) (Table 2). Salvaged autologous and allogenic blood transfusion was not associated with sex, age 60 years or older, or hospital LOS of 4 days or more (Table 3). The groups’ mean hemoglobin levels, measured the morning of postoperative day 1, were similar: 10.6 g/dL (range, 8.5-12.4 g/dL) for the DA group and 10.3 g/dL (range 8.6-12.3 g/dL) for the posterior group (Table 2).

In-hospital complications were uncommon in both groups (5% vs 14%; P = .61) (Table 2). One patient in the posterior group sustained a unilateral dislocation the day of surgery, and closed reduction was required; other complications (1 ileus, 2 tachyarrhythmias) did not require intervention. Ninety-day complications were also rare; 1 patient in the posterior group developed a hematoma with wound drainage, and this was successfully managed conservatively. There were no reoperations or readmissions in either group (Table 2).

Discussion

Although bilateral procedures account for less than 1% of THAs in the United States,¹¹ debate about their role in patients with severe bilateral hip disease continues. The potential benefits of a single episode of care must be weighed against the slightly increased risk for systemic complications.^7,10-15 Recent innovations in perioperative management have been shown to minimize complications,¹⁵ but it is unclear whether surgical approach affects perioperative outcomes. Our goals in this study were to evaluate operative times, transfusion requirements, hospital discharge data, and 90-day complication rates in patients who underwent simultaneous bilateral THAs through either the DA approach or the posterior approach.

Patients in our DA group had longer operative and anesthesia times. Other studies have found longer operative times for the DA approach relative to the posterior approach in unilateral THAs.¹⁸ One potential benefit of the DA approach in the setting of simultaneous bilateral THAs is the ability to prepare and drape both sides before surgery and thereby keep the interruption between hips to a minimum. In the present study, however, time saved during turnover between hips was overshadowed by the time added for each THA.

Although it was uncommon for complications to occur within 90 days after surgery in this study, many patients are needed to fully investigate these rare occurrences. Because of inherent selection bias, these risks are difficult to directly compare in patients who undergo unilateral procedures. Although small studies have failed to clarify the issue,^7,19,20 a recent review of the almost 20,000 bilateral THA cases in the US Nationwide Inpatient Sample database found that bilateral (vs unilateral) THAs were associated with increased risk of local and systemic complications.¹¹ Therefore, bilateral THAs should be reserved for select cases, with attention given to excluding patients with preexisting cardiopulmonary disease and providing appropriate preoperative counseling.

Most studies have reported a higher transfusion rate in bilateral THAs relative to staged procedures.^7,21-23 Allogenic blood transfusion leads to immune suppression, coagulopathy, and other systemic effects in general, and has been specifically associated with infection in patients who undergo total joint arthroplasty.^24-29 Parvizi and colleagues¹⁷ reported reduced blood loss and fewer blood transfusions in patients who had simultaneous bilateral THAs through the DA approach, compared with the direct lateral approach. Patients in our DA group received more salvaged autologous blood, which we suppose was a function of longer operative times. However, postoperative hemoglobin levels and allogenic blood transfusion rates were statistically similar between the 2 groups. It is important to consider the increased risk of required allogenic blood transfusion associated with simultaneous bilateral THAs, but it is not fully clear if this risk is lower in THAs performed through the DA approach relative to other approaches. In our experience, the required transfusion risk is limited in DA and posterior approaches with use of contemporary perioperative blood management strategies.

Although hospital LOS is longer with simultaneous bilateral THAs than with unilateral THAs, historically it is shorter than the combined LOS of staged bilateral THAs.²⁰ Patients in our study had a relatively short LOS after bilateral THAs, and there was no difference in LOS between groups. However, patients were more likely to be discharged home after bilateral THAs through the DA approach vs the posterior approach. Although discharge location was not affected by age, sex, ASA score, or LOS, unrecognized social factors unrelated to surgical approach likely influenced this finding.

This study should be interpreted in light of important limitations. Foremost, although data were prospectively collected, we examined them retrospectively. Thus, it is possible there may be unaccounted for differences between our DA and posterior THA groups. For example, the DA and posterior approaches were used by different surgeons with differing experience, technique, and preferences, all of which could have affected outcomes. Furthermore, our sample was relatively small (simultaneous bilateral THAs are performed relatively infrequently). Last, although anesthesia, pain management, blood conservation, and physical therapy were similar for the 2 groups, there was no standardized protocol for determining eligibility for simultaneous bilateral THAs.

In conclusion, we found that simultaneous bilateral THAs can be safely performed through either the DA approach or the posterior approach. Although the transition between hips is shorter with the DA approach, this time savings is overshadowed by the increased duration of each procedure. Transfusion rates are low in both groups, and in-hospital and 90-day complications are quite rare. Furthermore, patients can routinely be discharged home without elevating readmission rates. We will continue to perform simultaneous bilateral THAs through the DA approach or the posterior approach, according to surgeon preference.

Am J Orthop. 2016;45(6):E373-E378. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

End-stage osteoarthritis of the hip is a debilitating disease that is reliably treated with total hip arthroplasty (THA).¹ Up to 35% of patients who undergo THA eventually require contralateral THA.^2,3 In patients who present with advanced bilateral disease and undergo unilateral THA, the risk of ultimately requiring a contralateral procedure is as high as 97%.^3-6 In patients with bilateral hip disease, function is not fully optimized until both hips have been replaced, particularly in the setting of fixed flexion contractures.^7-9 Naturally, there has been some interest in simultaneous bilateral THAs for select patients.

The potential benefits of bilateral THAs over staged procedures include faster overall rehabilitation, exposure to a single anesthetic, reduced hospital length of stay (LOS), and cost savings.^10-12 However, opinion on recommending bilateral THAs is mixed. Although bilateral procedures historically have been fraught with perioperative complications,^13,14 advances in surgical and anesthetic techniques have led to improved outcomes.¹⁵ Whether surgical approach is a factor in these outcomes is unclear.

The popularity of the direct anterior (DA) approach for THA has increased in recent years.¹⁶ Although the relative advantages of various approaches remain in debate, one potential benefit of the DA approach is supine positioning, which allows simultaneous bilateral THAs to be performed without the need for repositioning before proceeding with the contralateral side. However, simultaneous bilateral THAs performed through the DA approach and those performed through other surgical approaches are lacking in comparative outcomes data.¹⁷In this study, we evaluated operative times, transfusion requirements, hospital discharge data, and 90-day complication rates in patients who had simultaneous bilateral THAs through either the DA approach or the posterior approach.

Methods

Study Design

This single-center study was conducted at the Mayo Clinic in Rochester, Minnesota. After obtaining approval from our Institutional Review Board, we performed a retrospective cohort analysis. We used our institution’s total joint registry to identify all patients who underwent simultaneous bilateral THAs through either the DA approach or the posterior approach. The first bilateral THAs to use the DA approach at our institution were performed in 2012. To ensure that the DA and posterior groups’ perioperative management would be similar, we included only cases performed between 2012 and 2014.

There were 19 patients in the DA group and 21 in the posterior group. The groups were similar in mean age (54 vs 54 years; P = .90), sex (73% vs 57% males; P = .33), body mass index (BMI; 25 vs 28 kg/m²; P = .38), preoperative hemoglobin level (14.3 vs 14.0 g/dL; P = .37), preoperative diagnosis (71.1% vs 78.6% degenerative joint disease; P = .75), and American Society of Anesthesiologists (ASA) score (1.9 vs 2.0; P = .63) (Table 1).

Patient Care

All cases were performed by 1 of 3 dedicated arthroplasty surgeons (Dr. Taunton, Dr. Sierra, Dr. Trousdale). Dr. Taunton exclusively uses the DA approach, and Dr. Sierra and Dr. Trousdale exclusively use the posterior approach. Patients in both groups received preoperative medical clearance and attended the same preoperative education class.

Patients in the DA group were positioned supine on an orthopedic table that allows hyperextension and adduction of the operative leg. Both hips were prepared and draped simultaneously. The most symptomatic hip was operated on first, with a sterile drape covering the contralateral hip. Between hips, fluoroscopy was moved to the other side of the operative suite, but no changes in positioning or preparation were necessary. A deep drain was placed on each side, and then was removed the morning of postoperative day 1. The same set of instruments was used on both sides.

Patients in the posterior group were positioned lateral on a regular operative table with hip rests. The most symptomatic hip was operated on first. After wound closure and dressing application, the patient was flipped to allow access to the contralateral hip and was prepared and draped again. The same instruments were used on each side. Drains were not used.

All patients received the same comprehensive multimodal pain management, which combined general and epidural anesthesia (remaining in place until postoperative day 2) and included an oral pain regimen of scheduled acetaminophen and as-needed tramadol and oxycodone. In all cases, intraoperative blood salvage and intravenous tranexamic acid (1 g at time of incision on first hip, 1 g at wound closure on second hip) were used. Preoperative autologous blood donation was not used. For deep vein thrombosis prophylaxis, patients were treated with bilateral sequential compression devices while hospitalized, but chemoprophylaxis was different between groups. Patients in the DA group received prophylactic low-molecular-weight heparin for 10 days, followed by twice-daily aspirin (325 mg) for 4 weeks. Patients in the posterior group received warfarin (goal international normalized ratio, 1.7-2.2) for 3 weeks, followed by twice-daily aspirin (325 mg) for 3 weeks. The decision to transfuse allogenic red blood cells was made by the treating surgeon, based on standardized hospital protocols, wherein patients are transfused for hemoglobin levels under 7.0 g/dL, or for hemoglobin levels less than 8.0 g/dL in the presence of persistent symptoms. All patients received care on an orthopedic specialty floor and were assisted by the same physical therapists. Discharge disposition was coordinated with the same group of social workers.

Two to 3 months after surgery, patients returned for routine examination and radiographs. All patients were followed up for at least 90 days.

Statistical Analysis

All outcomes were analyzed with appropriate summary statistics. Chi-square tests or logistic regression analyses (for categorical outcomes) were used to compare baseline covariates with perioperative outcomes, and 2-sample tests or Wilcoxon rank-sum tests were used to compare outcomes measured on a continuous scale. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated as appropriate. Operative time was calculated by adding time from incision to wound closure for both hips (room turnover time between hips was not included). Anesthesia time was defined as total time patients were in the operating room. All statistical tests were 2-sided, and the threshold for statistical significance was set at α = 0.05.

Results

Compared with patients who underwent simultaneous bilateral THAs through the posterior approach, patients who underwent simultaneous bilateral THAs through the DA approach had longer mean operative times (153 vs 106 min; P < .001) and anesthesia times (257 vs 221 min; P = .007). The 2 groups’ hospital stays were similar in length (3.1 vs 3.5 days; P = .31), but patients in the DA group were more likely to be discharged home (100.0% vs 71.4%; P = .02) (Table 2).

Patients in the DA group were more likely to have sufficient intraoperative blood salvage for autologous transfusion (89.5% vs 57.1%; OR, 6.4; 95% CI, 1.16-34.94; P = .03) (Table 3) and received more mean units of salvaged autologous blood (1.4 vs 0.5; P = .003) (Table 2). Allogenic blood was not given to any patients in the DA group, but 3 patients in the posterior group (14.3%) required allogenic blood transfusion (P = .23) (Table 2). Salvaged autologous and allogenic blood transfusion was not associated with sex, age 60 years or older, or hospital LOS of 4 days or more (Table 3). The groups’ mean hemoglobin levels, measured the morning of postoperative day 1, were similar: 10.6 g/dL (range, 8.5-12.4 g/dL) for the DA group and 10.3 g/dL (range 8.6-12.3 g/dL) for the posterior group (Table 2).

In-hospital complications were uncommon in both groups (5% vs 14%; P = .61) (Table 2). One patient in the posterior group sustained a unilateral dislocation the day of surgery, and closed reduction was required; other complications (1 ileus, 2 tachyarrhythmias) did not require intervention. Ninety-day complications were also rare; 1 patient in the posterior group developed a hematoma with wound drainage, and this was successfully managed conservatively. There were no reoperations or readmissions in either group (Table 2).

Discussion

Although bilateral procedures account for less than 1% of THAs in the United States,¹¹ debate about their role in patients with severe bilateral hip disease continues. The potential benefits of a single episode of care must be weighed against the slightly increased risk for systemic complications.^7,10-15 Recent innovations in perioperative management have been shown to minimize complications,¹⁵ but it is unclear whether surgical approach affects perioperative outcomes. Our goals in this study were to evaluate operative times, transfusion requirements, hospital discharge data, and 90-day complication rates in patients who underwent simultaneous bilateral THAs through either the DA approach or the posterior approach.

Patients in our DA group had longer operative and anesthesia times. Other studies have found longer operative times for the DA approach relative to the posterior approach in unilateral THAs.¹⁸ One potential benefit of the DA approach in the setting of simultaneous bilateral THAs is the ability to prepare and drape both sides before surgery and thereby keep the interruption between hips to a minimum. In the present study, however, time saved during turnover between hips was overshadowed by the time added for each THA.

Although it was uncommon for complications to occur within 90 days after surgery in this study, many patients are needed to fully investigate these rare occurrences. Because of inherent selection bias, these risks are difficult to directly compare in patients who undergo unilateral procedures. Although small studies have failed to clarify the issue,^7,19,20 a recent review of the almost 20,000 bilateral THA cases in the US Nationwide Inpatient Sample database found that bilateral (vs unilateral) THAs were associated with increased risk of local and systemic complications.¹¹ Therefore, bilateral THAs should be reserved for select cases, with attention given to excluding patients with preexisting cardiopulmonary disease and providing appropriate preoperative counseling.

Most studies have reported a higher transfusion rate in bilateral THAs relative to staged procedures.^7,21-23 Allogenic blood transfusion leads to immune suppression, coagulopathy, and other systemic effects in general, and has been specifically associated with infection in patients who undergo total joint arthroplasty.^24-29 Parvizi and colleagues¹⁷ reported reduced blood loss and fewer blood transfusions in patients who had simultaneous bilateral THAs through the DA approach, compared with the direct lateral approach. Patients in our DA group received more salvaged autologous blood, which we suppose was a function of longer operative times. However, postoperative hemoglobin levels and allogenic blood transfusion rates were statistically similar between the 2 groups. It is important to consider the increased risk of required allogenic blood transfusion associated with simultaneous bilateral THAs, but it is not fully clear if this risk is lower in THAs performed through the DA approach relative to other approaches. In our experience, the required transfusion risk is limited in DA and posterior approaches with use of contemporary perioperative blood management strategies.

Although hospital LOS is longer with simultaneous bilateral THAs than with unilateral THAs, historically it is shorter than the combined LOS of staged bilateral THAs.²⁰ Patients in our study had a relatively short LOS after bilateral THAs, and there was no difference in LOS between groups. However, patients were more likely to be discharged home after bilateral THAs through the DA approach vs the posterior approach. Although discharge location was not affected by age, sex, ASA score, or LOS, unrecognized social factors unrelated to surgical approach likely influenced this finding.

This study should be interpreted in light of important limitations. Foremost, although data were prospectively collected, we examined them retrospectively. Thus, it is possible there may be unaccounted for differences between our DA and posterior THA groups. For example, the DA and posterior approaches were used by different surgeons with differing experience, technique, and preferences, all of which could have affected outcomes. Furthermore, our sample was relatively small (simultaneous bilateral THAs are performed relatively infrequently). Last, although anesthesia, pain management, blood conservation, and physical therapy were similar for the 2 groups, there was no standardized protocol for determining eligibility for simultaneous bilateral THAs.

In conclusion, we found that simultaneous bilateral THAs can be safely performed through either the DA approach or the posterior approach. Although the transition between hips is shorter with the DA approach, this time savings is overshadowed by the increased duration of each procedure. Transfusion rates are low in both groups, and in-hospital and 90-day complications are quite rare. Furthermore, patients can routinely be discharged home without elevating readmission rates. We will continue to perform simultaneous bilateral THAs through the DA approach or the posterior approach, according to surgeon preference.

Am J Orthop. 2016;45(6):E373-E378. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

End-stage osteoarthritis of the hip is a debilitating disease that is reliably treated with total hip arthroplasty (THA).¹ Up to 35% of patients who undergo THA eventually require contralateral THA.^2,3 In patients who present with advanced bilateral disease and undergo unilateral THA, the risk of ultimately requiring a contralateral procedure is as high as 97%.^3-6 In patients with bilateral hip disease, function is not fully optimized until both hips have been replaced, particularly in the setting of fixed flexion contractures.^7-9 Naturally, there has been some interest in simultaneous bilateral THAs for select patients.

The potential benefits of bilateral THAs over staged procedures include faster overall rehabilitation, exposure to a single anesthetic, reduced hospital length of stay (LOS), and cost savings.^10-12 However, opinion on recommending bilateral THAs is mixed. Although bilateral procedures historically have been fraught with perioperative complications,^13,14 advances in surgical and anesthetic techniques have led to improved outcomes.¹⁵ Whether surgical approach is a factor in these outcomes is unclear.

The popularity of the direct anterior (DA) approach for THA has increased in recent years.¹⁶ Although the relative advantages of various approaches remain in debate, one potential benefit of the DA approach is supine positioning, which allows simultaneous bilateral THAs to be performed without the need for repositioning before proceeding with the contralateral side. However, simultaneous bilateral THAs performed through the DA approach and those performed through other surgical approaches are lacking in comparative outcomes data.¹⁷In this study, we evaluated operative times, transfusion requirements, hospital discharge data, and 90-day complication rates in patients who had simultaneous bilateral THAs through either the DA approach or the posterior approach.

Methods

Study Design

This single-center study was conducted at the Mayo Clinic in Rochester, Minnesota. After obtaining approval from our Institutional Review Board, we performed a retrospective cohort analysis. We used our institution’s total joint registry to identify all patients who underwent simultaneous bilateral THAs through either the DA approach or the posterior approach. The first bilateral THAs to use the DA approach at our institution were performed in 2012. To ensure that the DA and posterior groups’ perioperative management would be similar, we included only cases performed between 2012 and 2014.

There were 19 patients in the DA group and 21 in the posterior group. The groups were similar in mean age (54 vs 54 years; P = .90), sex (73% vs 57% males; P = .33), body mass index (BMI; 25 vs 28 kg/m²; P = .38), preoperative hemoglobin level (14.3 vs 14.0 g/dL; P = .37), preoperative diagnosis (71.1% vs 78.6% degenerative joint disease; P = .75), and American Society of Anesthesiologists (ASA) score (1.9 vs 2.0; P = .63) (Table 1).

Patient Care

All cases were performed by 1 of 3 dedicated arthroplasty surgeons (Dr. Taunton, Dr. Sierra, Dr. Trousdale). Dr. Taunton exclusively uses the DA approach, and Dr. Sierra and Dr. Trousdale exclusively use the posterior approach. Patients in both groups received preoperative medical clearance and attended the same preoperative education class.

Patients in the DA group were positioned supine on an orthopedic table that allows hyperextension and adduction of the operative leg. Both hips were prepared and draped simultaneously. The most symptomatic hip was operated on first, with a sterile drape covering the contralateral hip. Between hips, fluoroscopy was moved to the other side of the operative suite, but no changes in positioning or preparation were necessary. A deep drain was placed on each side, and then was removed the morning of postoperative day 1. The same set of instruments was used on both sides.

Patients in the posterior group were positioned lateral on a regular operative table with hip rests. The most symptomatic hip was operated on first. After wound closure and dressing application, the patient was flipped to allow access to the contralateral hip and was prepared and draped again. The same instruments were used on each side. Drains were not used.

All patients received the same comprehensive multimodal pain management, which combined general and epidural anesthesia (remaining in place until postoperative day 2) and included an oral pain regimen of scheduled acetaminophen and as-needed tramadol and oxycodone. In all cases, intraoperative blood salvage and intravenous tranexamic acid (1 g at time of incision on first hip, 1 g at wound closure on second hip) were used. Preoperative autologous blood donation was not used. For deep vein thrombosis prophylaxis, patients were treated with bilateral sequential compression devices while hospitalized, but chemoprophylaxis was different between groups. Patients in the DA group received prophylactic low-molecular-weight heparin for 10 days, followed by twice-daily aspirin (325 mg) for 4 weeks. Patients in the posterior group received warfarin (goal international normalized ratio, 1.7-2.2) for 3 weeks, followed by twice-daily aspirin (325 mg) for 3 weeks. The decision to transfuse allogenic red blood cells was made by the treating surgeon, based on standardized hospital protocols, wherein patients are transfused for hemoglobin levels under 7.0 g/dL, or for hemoglobin levels less than 8.0 g/dL in the presence of persistent symptoms. All patients received care on an orthopedic specialty floor and were assisted by the same physical therapists. Discharge disposition was coordinated with the same group of social workers.

Two to 3 months after surgery, patients returned for routine examination and radiographs. All patients were followed up for at least 90 days.

Statistical Analysis

All outcomes were analyzed with appropriate summary statistics. Chi-square tests or logistic regression analyses (for categorical outcomes) were used to compare baseline covariates with perioperative outcomes, and 2-sample tests or Wilcoxon rank-sum tests were used to compare outcomes measured on a continuous scale. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated as appropriate. Operative time was calculated by adding time from incision to wound closure for both hips (room turnover time between hips was not included). Anesthesia time was defined as total time patients were in the operating room. All statistical tests were 2-sided, and the threshold for statistical significance was set at α = 0.05.

Results

Compared with patients who underwent simultaneous bilateral THAs through the posterior approach, patients who underwent simultaneous bilateral THAs through the DA approach had longer mean operative times (153 vs 106 min; P < .001) and anesthesia times (257 vs 221 min; P = .007). The 2 groups’ hospital stays were similar in length (3.1 vs 3.5 days; P = .31), but patients in the DA group were more likely to be discharged home (100.0% vs 71.4%; P = .02) (Table 2).

Patients in the DA group were more likely to have sufficient intraoperative blood salvage for autologous transfusion (89.5% vs 57.1%; OR, 6.4; 95% CI, 1.16-34.94; P = .03) (Table 3) and received more mean units of salvaged autologous blood (1.4 vs 0.5; P = .003) (Table 2). Allogenic blood was not given to any patients in the DA group, but 3 patients in the posterior group (14.3%) required allogenic blood transfusion (P = .23) (Table 2). Salvaged autologous and allogenic blood transfusion was not associated with sex, age 60 years or older, or hospital LOS of 4 days or more (Table 3). The groups’ mean hemoglobin levels, measured the morning of postoperative day 1, were similar: 10.6 g/dL (range, 8.5-12.4 g/dL) for the DA group and 10.3 g/dL (range 8.6-12.3 g/dL) for the posterior group (Table 2).

In-hospital complications were uncommon in both groups (5% vs 14%; P = .61) (Table 2). One patient in the posterior group sustained a unilateral dislocation the day of surgery, and closed reduction was required; other complications (1 ileus, 2 tachyarrhythmias) did not require intervention. Ninety-day complications were also rare; 1 patient in the posterior group developed a hematoma with wound drainage, and this was successfully managed conservatively. There were no reoperations or readmissions in either group (Table 2).

Discussion

Although bilateral procedures account for less than 1% of THAs in the United States,¹¹ debate about their role in patients with severe bilateral hip disease continues. The potential benefits of a single episode of care must be weighed against the slightly increased risk for systemic complications.^7,10-15 Recent innovations in perioperative management have been shown to minimize complications,¹⁵ but it is unclear whether surgical approach affects perioperative outcomes. Our goals in this study were to evaluate operative times, transfusion requirements, hospital discharge data, and 90-day complication rates in patients who underwent simultaneous bilateral THAs through either the DA approach or the posterior approach.

Patients in our DA group had longer operative and anesthesia times. Other studies have found longer operative times for the DA approach relative to the posterior approach in unilateral THAs.¹⁸ One potential benefit of the DA approach in the setting of simultaneous bilateral THAs is the ability to prepare and drape both sides before surgery and thereby keep the interruption between hips to a minimum. In the present study, however, time saved during turnover between hips was overshadowed by the time added for each THA.

Although it was uncommon for complications to occur within 90 days after surgery in this study, many patients are needed to fully investigate these rare occurrences. Because of inherent selection bias, these risks are difficult to directly compare in patients who undergo unilateral procedures. Although small studies have failed to clarify the issue,^7,19,20 a recent review of the almost 20,000 bilateral THA cases in the US Nationwide Inpatient Sample database found that bilateral (vs unilateral) THAs were associated with increased risk of local and systemic complications.¹¹ Therefore, bilateral THAs should be reserved for select cases, with attention given to excluding patients with preexisting cardiopulmonary disease and providing appropriate preoperative counseling.

Most studies have reported a higher transfusion rate in bilateral THAs relative to staged procedures.^7,21-23 Allogenic blood transfusion leads to immune suppression, coagulopathy, and other systemic effects in general, and has been specifically associated with infection in patients who undergo total joint arthroplasty.^24-29 Parvizi and colleagues¹⁷ reported reduced blood loss and fewer blood transfusions in patients who had simultaneous bilateral THAs through the DA approach, compared with the direct lateral approach. Patients in our DA group received more salvaged autologous blood, which we suppose was a function of longer operative times. However, postoperative hemoglobin levels and allogenic blood transfusion rates were statistically similar between the 2 groups. It is important to consider the increased risk of required allogenic blood transfusion associated with simultaneous bilateral THAs, but it is not fully clear if this risk is lower in THAs performed through the DA approach relative to other approaches. In our experience, the required transfusion risk is limited in DA and posterior approaches with use of contemporary perioperative blood management strategies.

Although hospital LOS is longer with simultaneous bilateral THAs than with unilateral THAs, historically it is shorter than the combined LOS of staged bilateral THAs.²⁰ Patients in our study had a relatively short LOS after bilateral THAs, and there was no difference in LOS between groups. However, patients were more likely to be discharged home after bilateral THAs through the DA approach vs the posterior approach. Although discharge location was not affected by age, sex, ASA score, or LOS, unrecognized social factors unrelated to surgical approach likely influenced this finding.

This study should be interpreted in light of important limitations. Foremost, although data were prospectively collected, we examined them retrospectively. Thus, it is possible there may be unaccounted for differences between our DA and posterior THA groups. For example, the DA and posterior approaches were used by different surgeons with differing experience, technique, and preferences, all of which could have affected outcomes. Furthermore, our sample was relatively small (simultaneous bilateral THAs are performed relatively infrequently). Last, although anesthesia, pain management, blood conservation, and physical therapy were similar for the 2 groups, there was no standardized protocol for determining eligibility for simultaneous bilateral THAs.

In conclusion, we found that simultaneous bilateral THAs can be safely performed through either the DA approach or the posterior approach. Although the transition between hips is shorter with the DA approach, this time savings is overshadowed by the increased duration of each procedure. Transfusion rates are low in both groups, and in-hospital and 90-day complications are quite rare. Furthermore, patients can routinely be discharged home without elevating readmission rates. We will continue to perform simultaneous bilateral THAs through the DA approach or the posterior approach, according to surgeon preference.

Am J Orthop. 2016;45(6):E373-E378. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

Aneurysmal bone cysts (ABC) are expansile, hemorrhagic, non-neoplastic lesions that can be locally destructive¹ and that can arise either de novo or secondary to another benign or malignant lesion.² Although primary and secondary ABCs typically are benign, there are cases of malignant degeneration of primary ABCs, though the transformation arises almost exclusively in the context of prior radiation exposure.^3-5 Malignant change without history of irradiation is rare; only 6 such cases have been reported.^5-10 In 4 of these cases, the transformation was to osteosarcoma.^5,8-10

Here we report on an ABC that degenerated into a fibroblastic osteosarcoma—the fifth such case in the medical literature. In addition to reviewing the earlier cases, we describe the radiologic and histologic underpinnings of this diagnosis and the insight that they provide into the pathogenesis of this rare process. Although the prevailing view is that ABCs are benign, it is important to know these lesions have the potential to undergo malignant transformation, even in the absence of prior radiation exposure. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A healthy and previously asymptomatic 37-year-old man presented with thigh pain after a minor fall onto a couch. Radiographs showed a diaphyseal femoral pathologic fracture adjacent to a small but benign-appearing cystic lesion (Figures 1A, 1B).

Two years later, the patient had a bicycle accident and, after 2 weeks of significantly increased thigh swelling, presented to the emergency department at the referring institution. Radiographs showed a lytic lesion in the femoral diaphysis that was highly suspicious for malignancy (Figures 3A, 3B).

Discussion

Aneurysmal bone cysts are expansile, hemorrhagic, locally destructive lesions that generally develop within the first 3 decades of life. Ever since they were first described by Jaffe and Lichtenstein¹¹ in 1942, the most widely accepted theory of their pathogenesis has been that they begin as a benign reactive vascular process.¹² However, more recent molecular studies by Oliveira and colleagues¹³ and Panoutsakopoulos and colleagues¹⁴ have demonstrated a clonal neoplastic basis for primary ABCs related to cytogenetic upregulation of oncogenes USP6 and CDH11 after translocation of 17p13 and 16q22.

Given the clonal nature of these lesions, it is surprising that malignant transformation is so rare. Until now, there have been only 4 reports of an ABC undergoing malignant degeneration to osteosarcoma without prior radiation exposure.

Aneurysmal bone cysts (ABC) are expansile, hemorrhagic, non-neoplastic lesions that can be locally destructive¹ and that can arise either de novo or secondary to another benign or malignant lesion.² Although primary and secondary ABCs typically are benign, there are cases of malignant degeneration of primary ABCs, though the transformation arises almost exclusively in the context of prior radiation exposure.^3-5 Malignant change without history of irradiation is rare; only 6 such cases have been reported.^5-10 In 4 of these cases, the transformation was to osteosarcoma.^5,8-10

Here we report on an ABC that degenerated into a fibroblastic osteosarcoma—the fifth such case in the medical literature. In addition to reviewing the earlier cases, we describe the radiologic and histologic underpinnings of this diagnosis and the insight that they provide into the pathogenesis of this rare process. Although the prevailing view is that ABCs are benign, it is important to know these lesions have the potential to undergo malignant transformation, even in the absence of prior radiation exposure. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A healthy and previously asymptomatic 37-year-old man presented with thigh pain after a minor fall onto a couch. Radiographs showed a diaphyseal femoral pathologic fracture adjacent to a small but benign-appearing cystic lesion (Figures 1A, 1B).

Two years later, the patient had a bicycle accident and, after 2 weeks of significantly increased thigh swelling, presented to the emergency department at the referring institution. Radiographs showed a lytic lesion in the femoral diaphysis that was highly suspicious for malignancy (Figures 3A, 3B).

Discussion

Aneurysmal bone cysts are expansile, hemorrhagic, locally destructive lesions that generally develop within the first 3 decades of life. Ever since they were first described by Jaffe and Lichtenstein¹¹ in 1942, the most widely accepted theory of their pathogenesis has been that they begin as a benign reactive vascular process.¹² However, more recent molecular studies by Oliveira and colleagues¹³ and Panoutsakopoulos and colleagues¹⁴ have demonstrated a clonal neoplastic basis for primary ABCs related to cytogenetic upregulation of oncogenes USP6 and CDH11 after translocation of 17p13 and 16q22.

Given the clonal nature of these lesions, it is surprising that malignant transformation is so rare. Until now, there have been only 4 reports of an ABC undergoing malignant degeneration to osteosarcoma without prior radiation exposure.

Aneurysmal bone cysts (ABC) are expansile, hemorrhagic, non-neoplastic lesions that can be locally destructive¹ and that can arise either de novo or secondary to another benign or malignant lesion.² Although primary and secondary ABCs typically are benign, there are cases of malignant degeneration of primary ABCs, though the transformation arises almost exclusively in the context of prior radiation exposure.^3-5 Malignant change without history of irradiation is rare; only 6 such cases have been reported.^5-10 In 4 of these cases, the transformation was to osteosarcoma.^5,8-10

Here we report on an ABC that degenerated into a fibroblastic osteosarcoma—the fifth such case in the medical literature. In addition to reviewing the earlier cases, we describe the radiologic and histologic underpinnings of this diagnosis and the insight that they provide into the pathogenesis of this rare process. Although the prevailing view is that ABCs are benign, it is important to know these lesions have the potential to undergo malignant transformation, even in the absence of prior radiation exposure. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A healthy and previously asymptomatic 37-year-old man presented with thigh pain after a minor fall onto a couch. Radiographs showed a diaphyseal femoral pathologic fracture adjacent to a small but benign-appearing cystic lesion (Figures 1A, 1B).

Two years later, the patient had a bicycle accident and, after 2 weeks of significantly increased thigh swelling, presented to the emergency department at the referring institution. Radiographs showed a lytic lesion in the femoral diaphysis that was highly suspicious for malignancy (Figures 3A, 3B).

Discussion

Aneurysmal bone cysts are expansile, hemorrhagic, locally destructive lesions that generally develop within the first 3 decades of life. Ever since they were first described by Jaffe and Lichtenstein¹¹ in 1942, the most widely accepted theory of their pathogenesis has been that they begin as a benign reactive vascular process.¹² However, more recent molecular studies by Oliveira and colleagues¹³ and Panoutsakopoulos and colleagues¹⁴ have demonstrated a clonal neoplastic basis for primary ABCs related to cytogenetic upregulation of oncogenes USP6 and CDH11 after translocation of 17p13 and 16q22.

Given the clonal nature of these lesions, it is surprising that malignant transformation is so rare. Until now, there have been only 4 reports of an ABC undergoing malignant degeneration to osteosarcoma without prior radiation exposure.

An increasingly number of patients with symptomatic isolated medial unicompartmental knee osteoarthritis (OA) are too young and too functionally active to be ideal candidates for total knee arthroplasty (TKA). Isolated medial compartment OA occurs in 10% to 29.5% of all cases, whereas the isolated lateral variant is less common, with a reported incidence of 1% to 7%.^1,2 In 1961, Jackson and Waugh³ introduced the high tibial osteotomy (HTO) as a surgical treatment for single-compartment OA. This procedure is designed to increase the life span of articular cartilage by unloading and redistributing the mechanical forces over the nonaffected compartment. Unicompartmental knee arthroplasty (UKA) was introduced in the 1970s as an alternative to TKA or HTO for single-compartment OA.

Since the introduction of these methods, there has been debate about which patients are appropriate candidates for each procedure. Improved surgical techniques and implant designs have led surgeons to reexamine the selection criteria and contraindications for these procedures. Furthermore, given the increasing popularity and use of UKA, the question arises as to whether HTO still has a role in clinical practice in the surgical treatment of medial OA of the knee.

To clarify current ambiguities, we review the modern indications, subjective outcome scores, and survivorship results of UKA and HTO in the treatment of isolated medial compartment degeneration of the knee. In addition, in a thorough review of the literature, we evaluate global trends in the use of both methods.

High Tibial Osteotomy for Medial Compartment OA

Indications

Before the introduction of TKA and UKA for single-compartment OA, surgical management consisted of HTO. When the mechanical axis is slightly overcorrected, the medial compartment is decompressed, ensuring tissue viability and delaying progressive compartment degeneration.

Traditionally, HTO is indicated for young (age <60 years), normal-weight, active patients with radiographic single-compartment OA.⁶ The knee should be stable and have good range of motion (ROM; flexion >120°), and pain should be localized to the tibiofemoral joint line.

Over the past few decades, numerous authors have reported similar inclusion criteria, clarifying their definition. This definition should be further refined in order to optimize survivorship and clinical outcomes.

Confirming age as an inclusion criterion for HTO, Trieb and colleagues⁷ found that the risk of failure was significantly (P = .046) higher for HTO patients older than 65 years than for those younger than 65 years (relative risk, 1.5). This finding agrees with findings of other studies, which suggests that, in particular, young patients benefit from HTO.^8-11

Moreover, there is a clear relation between HTO survival and obesity. In a study of 159 CWHTOs, Akizuki and colleagues¹² reported that preoperative body mass index (BMI) higher than 27.5 kg/m² was a significant risk factor for early failure. Using BMI higher than 30 kg/m² as a threshold, Howells and colleagues⁹ found significantly inferior Knee Society Score (KSS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) results for the obese group 5 years after HTO.

Radiographic evidence of severe preoperative compartment degeneration has been associated with early conversion to TKA. Flecher and colleagues¹¹ and van Raaij and colleagues¹³ both concluded the best long-term survival grades are achieved in HTO patients with mild compartment OA (Ahlbäck^14 grade I). The question then becomes whether these patients should be treated nonoperatively instead.^15,16The literature supports strict adherence to inclusion criteria in the selection of a potential HTO candidate. Age, BMI, and the preoperative state of OA should be taken into account in order to optimize clinical outcome and survivorship results in patients about to undergo HTO.

Outcomes

Multiple authors have described or compared the midterm or long-term results of the various surgical HTO techniques. Howells and colleagues⁹ noted overall survival rates of 87% (5 years after CWHTO) and 79% (10 years after CWHTO). Over the 10-year postoperative period, there was significant deterioration in clinical outcome scores and survivorship. Others authors have had similar findings.^17-19 van Raaij and colleagues¹³ found that the 10-year probability of survival after CWHTO was 75%. In 455 patients who underwent lateral CWHTO, Hui and colleagues⁸ found that 5-year probability of survival was 95%, 10-year probability was 79%, and 15-year probability was 56%. Niinimäki and colleagues¹⁰ used the Finnish Arthroplasty Register to report HTO survivorship at a national level. Using conversion to TKA as a cutoff, they noted 5-year survivorship of 89% and 10-year survivorship of 73%. To our knowledge, 2 groups, both in Japan, have reported substantially higher 15-year survival rates: 90%¹² and 93%.²⁰ The authors acknowledged that their results were significantly better than in other countries and that Japanese lifestyle, culture, and body habitus therefore require further investigation. At this time, it is not possible to compare their results with Western results.

In an attempt to compare the different survival rates of the various HTO techniques, Schallberger and colleagues²¹ conducted a retrospective study of OWHTOs and CWHTOs. At median follow-up of 16.5 years, comparative survival rates showed a trend of deterioration. Although data were limited, there were no significant differences in survival or functional outcome between the 2 techniques. In a recent randomized clinical trial, Duivenvoorden and colleagues⁵ compared these techniques’ midterm results (mean follow-up, 6 years). Clinical outcomes were not significantly different. There were more complications in the OWHTO group and more conversions to TKA in the CWHTO group. Considering these results, the authors suggested OWHTO without autologous bone graft is the best HTO treatment strategy for medial gonarthritis with varus malalignment of <12°.

The HTO results noted in these studies show a similar deteriorating trend; expected 10-year survivorship is 75%. Although modern implants and surgical techniques are being used, evidence supporting use of one surgical HTO method over another is lacking.

UKA for Medial Compartment OA

Indications

Since it was first introduced in the 1970s, use of UKA for single-compartment OA has been a subject of debate. The high failure rates reported at the time raised skepticism about the new treatment.²² Kozinn and Scott²³ defined classic indications and contraindications. Indications included isolated medial or lateral compartment OA or osteonecrosis of the knee, age over 60 years, and weight under 82 kg. In addition, the angular deformity of the affected lower extremity had to be <15° and passively correctable to neutral at time of surgery. Last, the flexion contracture had to be <5°, and ideal ROM was 90°. Contraindications included high activity, age under 60 years, and inflammatory arthritis. Strict adherence led to improved implant survival and lower revision rates. Because of improved surgical techniques, modern implant designs, and accumulating experience with the procedure, the surgical indications for UKA have expanded. Exact thresholds for UKA inclusion, however, remain unclear.

The modern literature is overturning the traditional idea that UKA is not indicated for patients under age 60 years.²³ Using KSS, Thompson and colleagues²⁴ found that younger patients did better than older patients 2 years after UKA using various types of implants. Analyzing survivorship results, Heyse and colleagues²⁵ concluded that UKA can be successful in patients under age 60 years and reported a 15-year survivorship rate of 85.6% and excellent outcome scores. Other authors have had similar findings.^26-28

Evaluating the influence of weight, Thompson and colleagues²⁴ found obese patients did not have a higher revision rate but did have slower progression of improvement 2 years after UKA. Cavaignac and colleagues²⁹ concluded that, at minimum follow-up of 7 years (range, 7-22 years), weight did not influence UKA survivorship. Other authors^30-33 have found no significant influence of BMI on survival.

Reports on preoperative radiographic parameters that can potentially influence UKA results are limited. In 113 medial UKAs studied by Niinimäki and colleagues,³⁴ mild medial compartment degeneration, seen on preoperative radiographs, was associated with significantly higher failure rates. The authors concluded that other treatment options should be favored in the absence of severe isolated compartment OA.

Although the classic indications defined by Kozinn and Scott²³ have yielded good to excellent UKA results, improvements in implants and surgical techniques^35-38 have extended the criteria. The modern literature demonstrates that age and BMI should not be used as criteria for excluding UKA candidates. Radiographically, there should be significant isolated compartment degeneration in order to optimize patient-reported outcome and survivorship.

Outcomes

Improved implant designs and modern minimally invasive techniques have effected a change in outcome results and a renewed interest in implants. Over the past decade, multiple authors have described the various modern UKA implants and their survivorship. Reports published since UKA was introduced in the 1970s show a continual increase in implant survival. Koskinen and colleagues,³⁹ using Finnish Arthroplasty Register data on 1819 UKAs performed between 1985 and 2003, found 10-year survival rates of 81% for Oxford implants (Zimmer Biomet), 79% for Miller-Galante II (Zimmer Biomet), 78% for Duracon (Howmedica), and 53% for PCA unicompartmental knee (Howmedica). Heyse and colleagues²⁵ reported 10- and 15-year survivorship data (93.5% and 86.3%, respectively) for 223 patients under age 60 years at the time of their index surgery (Genesis Unicondylar implant, Smith & Nephew), performed between 1993 and 2005. KSS was good to excellent. Similar numbers in cohorts under age 60 years were reported by Schai and colleagues²⁶ using the PFC system (Johnson & Johnson) and by Price and colleagues²⁷ using the medial Oxford UKA. Both groups reported excellent survivorship rates: 93% at 2- to 6-year follow-up and 91% at 10-year follow-up. The outcome in older patients seems satisfactory as well. In another multicenter report, by Price and colleagues,⁴⁰ medial Oxford UKAs had a 15-year survival rate of 93%. Berger and colleagues⁴¹ reported similar numbers for the Miller-Galante prosthesis. Survival rates were 98% (10 years) and 95.7% (13 years), and 92% of patients had good to excellent Hospital for Special Surgery knee scores.

Although various modern implants have had good to excellent results, the historical question of what type of UKA to use (mobile or fixed-bearing) remains unanswered. To try to address it, Peersman and colleagues⁴² performed a systematic review of 44 papers (9463 knees). The 2 implant types had comparable revision rates. Another recent retrospective study tried to determine what is crucial for implant survival: implant design or surgeon experience.⁴³ The authors concluded that prosthetic component positioning is key. Other authors have reported high-volume centers are crucial for satisfactory UKA results and lower revision rates.^44-46

Results of these studies indicate that, where UKAs are being performed in volume, 10-year survivorship rates higher than 90% and good to excellent outcomes can be expected.

UKA vs HTO

Cohort studies that have directly compared the 2 treatment modalities are scarce, and most have been retrospective. In a prospective study, Stukenborg-Colsman and colleagues⁴⁷ randomized patients with medial compartment OA to undergo either CWHTO (32 patients) with a technique reported by Coventry⁴⁸ or UKA (28 patients) with the unicondylar knee sliding prosthesis, Tübingen pattern (Aesculap), between 1988 and 1991. Patients were assessed 2.5, 4.5, and 7.5 years after surgery. More postoperative complications were noted in the HTO group. At 7- to 10-year follow-up, 71% of the HTO group and 65% of the UKA group had excellent KSS. Mean ROM was 103° after UKA (range, 35°-140°) and 117° after HTO (range, 85°-135°) during the same assessment. Although differences were not significant, Kaplan-Meier survival analysis was 60% for HTO and 77% for UKA at 10 years. Results were not promising for the implants used, compared with other implants, but the authors concluded that, because of improvements in implant designs and image-guided techniques, better long-term success can be expected with UKA than with HTO.

In another prospective study, Börjesson and colleagues⁴⁹ evaluated pain during walking, ROM, British Orthopaedic Association (BOA) scores, and gait variables at 1- and 5-year follow-up. Patients with moderate medial OA (Ahlbäck¹⁴ grade I-III) were randomly selected to undergo CWHTO or UKA (Brigham, DePuy). There were no significant differences in BOA scores, ROM, or pain during walking between the 2 groups at 3 months, 1 year, and 5 years after surgery. Gait analysis showed a significant difference in favor of UKA only at 3 months after surgery. At 1- and 5-year follow-up, no significant differences were noted.

To clarify current ambiguities, Fu and colleagues⁵⁰ performed a systematic review of all (11) comparative studies. These studies had a total of 5840 (5081 UKA, 759 HTO) patients. Although ROM was significantly better for the HTO group than the UKA group, the UKA group had significantly better functional results. Walking after surgery was significantly faster for the UKA group. The authors suggested the difference might be attributed to the different postoperative regimens—HTO patients wore a whole-leg plaster cast for 6 weeks, and UKA patients were allowed immediate postoperative weight-bearing. Regarding rates of survival and complications, pooled data showed no significant differences. Despite these results, the authors acknowledged the limitation of available randomized clinical trials and the multiple techniques and implants used. We share their assertion that larger prospective controlled trials are needed. These are crucial to getting a definitive answer regarding which of the 2 treatment strategies should be used for isolated compartment OA.

Current Trends in Use of UKA and HTO

Evaluation of national registries and recent reports showed a global shift in use of both HTO and UKA. Despite the lack of national HTO registries, a few reports have described use of TKA, UKA, and HTO in Western populations over the past 2 decades. Using 1998-2007 data from the Swedish Knee Arthroplasty Register, W-Dahl and colleagues⁵¹ found a 3-fold increase in UKA use, whereas HTO use was halved over the same period. Niinimäki and colleagues⁵² reported similar findings with the Finnish National Hospital Discharge Register. They noted a steady 6.8% annual decrease in osteotomies, whereas UKA use increased sharply after the Oxford UKA was introduced (Phase 3; Biomet). These findings are consistent with several reports from North America. In their epidemiologic analysis covering the period 1985-1990, Wright and colleagues⁵³ found an 11% to 14% annual decrease in osteotomies among the elderly, compared with an annual decrease of only 3% to 4% among patients younger than 65 years. Nwachukwu and colleagues⁵⁴ recently compared UKA and HTO practice patterns between 2007 and 2011, using data from a large US private payer insurance database. They noted an annual growth rate of 4.7% in UKA use, compared with an annual 3.9% decrease in HTO use. Furthermore, based on their subgroup analysis, they speculated there was a demographic shift toward UKA, as opposed to TKA, particularly in older women. Bolognesi and colleagues⁵⁵ investigated further. Evaluating all Medicare beneficiaries who underwent knee arthroplasty in the United States between 2000 and 2009, they noted a 1.7-fold increase in TKA use and a 6.2-fold increase in UKA use. As there were no substantial changes in patient characteristics over that period, the authors hypothesized that a possible broadening of inclusion criteria may have led to the increased use of UKA.

There is a possible multifactorial explanation for the current global shift in favor of UKA. First, UKA was once a technically demanding procedure, but improved surgical techniques, image guidance, and robot assistance⁵⁶ have made it relatively less difficult. Second, UKA surgery is associated with lower reported perioperative morbidities.⁵⁷ We think these factors have contributed to the global trend of less HTO use and more UKA use in the treatment of unicompartmental OA.

Conclusion

The modern literature suggests the inclusion criteria for HTO have been well investigated and defined; the UKA criteria remain a matter of debate but seem to be expanding. Long-term survival results seem to favor UKA, though patient satisfaction with both procedures is good to excellent. The broadening range of inclusion criteria and consistent reports of durable outcomes, coupled with excellent patient satisfaction, likely explain the shift toward UKA in the treatment of isolated compartment degeneration.

Am J Orthop. 2016;45(6):E355-E361. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

An increasingly number of patients with symptomatic isolated medial unicompartmental knee osteoarthritis (OA) are too young and too functionally active to be ideal candidates for total knee arthroplasty (TKA). Isolated medial compartment OA occurs in 10% to 29.5% of all cases, whereas the isolated lateral variant is less common, with a reported incidence of 1% to 7%.^1,2 In 1961, Jackson and Waugh³ introduced the high tibial osteotomy (HTO) as a surgical treatment for single-compartment OA. This procedure is designed to increase the life span of articular cartilage by unloading and redistributing the mechanical forces over the nonaffected compartment. Unicompartmental knee arthroplasty (UKA) was introduced in the 1970s as an alternative to TKA or HTO for single-compartment OA.

Since the introduction of these methods, there has been debate about which patients are appropriate candidates for each procedure. Improved surgical techniques and implant designs have led surgeons to reexamine the selection criteria and contraindications for these procedures. Furthermore, given the increasing popularity and use of UKA, the question arises as to whether HTO still has a role in clinical practice in the surgical treatment of medial OA of the knee.

To clarify current ambiguities, we review the modern indications, subjective outcome scores, and survivorship results of UKA and HTO in the treatment of isolated medial compartment degeneration of the knee. In addition, in a thorough review of the literature, we evaluate global trends in the use of both methods.

High Tibial Osteotomy for Medial Compartment OA

Indications

Before the introduction of TKA and UKA for single-compartment OA, surgical management consisted of HTO. When the mechanical axis is slightly overcorrected, the medial compartment is decompressed, ensuring tissue viability and delaying progressive compartment degeneration.

Traditionally, HTO is indicated for young (age <60 years), normal-weight, active patients with radiographic single-compartment OA.⁶ The knee should be stable and have good range of motion (ROM; flexion >120°), and pain should be localized to the tibiofemoral joint line.

Over the past few decades, numerous authors have reported similar inclusion criteria, clarifying their definition. This definition should be further refined in order to optimize survivorship and clinical outcomes.

Confirming age as an inclusion criterion for HTO, Trieb and colleagues⁷ found that the risk of failure was significantly (P = .046) higher for HTO patients older than 65 years than for those younger than 65 years (relative risk, 1.5). This finding agrees with findings of other studies, which suggests that, in particular, young patients benefit from HTO.^8-11

Moreover, there is a clear relation between HTO survival and obesity. In a study of 159 CWHTOs, Akizuki and colleagues¹² reported that preoperative body mass index (BMI) higher than 27.5 kg/m² was a significant risk factor for early failure. Using BMI higher than 30 kg/m² as a threshold, Howells and colleagues⁹ found significantly inferior Knee Society Score (KSS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) results for the obese group 5 years after HTO.

Radiographic evidence of severe preoperative compartment degeneration has been associated with early conversion to TKA. Flecher and colleagues¹¹ and van Raaij and colleagues¹³ both concluded the best long-term survival grades are achieved in HTO patients with mild compartment OA (Ahlbäck^14 grade I). The question then becomes whether these patients should be treated nonoperatively instead.^15,16The literature supports strict adherence to inclusion criteria in the selection of a potential HTO candidate. Age, BMI, and the preoperative state of OA should be taken into account in order to optimize clinical outcome and survivorship results in patients about to undergo HTO.

Outcomes

Multiple authors have described or compared the midterm or long-term results of the various surgical HTO techniques. Howells and colleagues⁹ noted overall survival rates of 87% (5 years after CWHTO) and 79% (10 years after CWHTO). Over the 10-year postoperative period, there was significant deterioration in clinical outcome scores and survivorship. Others authors have had similar findings.^17-19 van Raaij and colleagues¹³ found that the 10-year probability of survival after CWHTO was 75%. In 455 patients who underwent lateral CWHTO, Hui and colleagues⁸ found that 5-year probability of survival was 95%, 10-year probability was 79%, and 15-year probability was 56%. Niinimäki and colleagues¹⁰ used the Finnish Arthroplasty Register to report HTO survivorship at a national level. Using conversion to TKA as a cutoff, they noted 5-year survivorship of 89% and 10-year survivorship of 73%. To our knowledge, 2 groups, both in Japan, have reported substantially higher 15-year survival rates: 90%¹² and 93%.²⁰ The authors acknowledged that their results were significantly better than in other countries and that Japanese lifestyle, culture, and body habitus therefore require further investigation. At this time, it is not possible to compare their results with Western results.

In an attempt to compare the different survival rates of the various HTO techniques, Schallberger and colleagues²¹ conducted a retrospective study of OWHTOs and CWHTOs. At median follow-up of 16.5 years, comparative survival rates showed a trend of deterioration. Although data were limited, there were no significant differences in survival or functional outcome between the 2 techniques. In a recent randomized clinical trial, Duivenvoorden and colleagues⁵ compared these techniques’ midterm results (mean follow-up, 6 years). Clinical outcomes were not significantly different. There were more complications in the OWHTO group and more conversions to TKA in the CWHTO group. Considering these results, the authors suggested OWHTO without autologous bone graft is the best HTO treatment strategy for medial gonarthritis with varus malalignment of <12°.

The HTO results noted in these studies show a similar deteriorating trend; expected 10-year survivorship is 75%. Although modern implants and surgical techniques are being used, evidence supporting use of one surgical HTO method over another is lacking.

UKA for Medial Compartment OA

Indications

Since it was first introduced in the 1970s, use of UKA for single-compartment OA has been a subject of debate. The high failure rates reported at the time raised skepticism about the new treatment.²² Kozinn and Scott²³ defined classic indications and contraindications. Indications included isolated medial or lateral compartment OA or osteonecrosis of the knee, age over 60 years, and weight under 82 kg. In addition, the angular deformity of the affected lower extremity had to be <15° and passively correctable to neutral at time of surgery. Last, the flexion contracture had to be <5°, and ideal ROM was 90°. Contraindications included high activity, age under 60 years, and inflammatory arthritis. Strict adherence led to improved implant survival and lower revision rates. Because of improved surgical techniques, modern implant designs, and accumulating experience with the procedure, the surgical indications for UKA have expanded. Exact thresholds for UKA inclusion, however, remain unclear.

The modern literature is overturning the traditional idea that UKA is not indicated for patients under age 60 years.²³ Using KSS, Thompson and colleagues²⁴ found that younger patients did better than older patients 2 years after UKA using various types of implants. Analyzing survivorship results, Heyse and colleagues²⁵ concluded that UKA can be successful in patients under age 60 years and reported a 15-year survivorship rate of 85.6% and excellent outcome scores. Other authors have had similar findings.^26-28

Evaluating the influence of weight, Thompson and colleagues²⁴ found obese patients did not have a higher revision rate but did have slower progression of improvement 2 years after UKA. Cavaignac and colleagues²⁹ concluded that, at minimum follow-up of 7 years (range, 7-22 years), weight did not influence UKA survivorship. Other authors^30-33 have found no significant influence of BMI on survival.

Reports on preoperative radiographic parameters that can potentially influence UKA results are limited. In 113 medial UKAs studied by Niinimäki and colleagues,³⁴ mild medial compartment degeneration, seen on preoperative radiographs, was associated with significantly higher failure rates. The authors concluded that other treatment options should be favored in the absence of severe isolated compartment OA.

Although the classic indications defined by Kozinn and Scott²³ have yielded good to excellent UKA results, improvements in implants and surgical techniques^35-38 have extended the criteria. The modern literature demonstrates that age and BMI should not be used as criteria for excluding UKA candidates. Radiographically, there should be significant isolated compartment degeneration in order to optimize patient-reported outcome and survivorship.

Outcomes

Improved implant designs and modern minimally invasive techniques have effected a change in outcome results and a renewed interest in implants. Over the past decade, multiple authors have described the various modern UKA implants and their survivorship. Reports published since UKA was introduced in the 1970s show a continual increase in implant survival. Koskinen and colleagues,³⁹ using Finnish Arthroplasty Register data on 1819 UKAs performed between 1985 and 2003, found 10-year survival rates of 81% for Oxford implants (Zimmer Biomet), 79% for Miller-Galante II (Zimmer Biomet), 78% for Duracon (Howmedica), and 53% for PCA unicompartmental knee (Howmedica). Heyse and colleagues²⁵ reported 10- and 15-year survivorship data (93.5% and 86.3%, respectively) for 223 patients under age 60 years at the time of their index surgery (Genesis Unicondylar implant, Smith & Nephew), performed between 1993 and 2005. KSS was good to excellent. Similar numbers in cohorts under age 60 years were reported by Schai and colleagues²⁶ using the PFC system (Johnson & Johnson) and by Price and colleagues²⁷ using the medial Oxford UKA. Both groups reported excellent survivorship rates: 93% at 2- to 6-year follow-up and 91% at 10-year follow-up. The outcome in older patients seems satisfactory as well. In another multicenter report, by Price and colleagues,⁴⁰ medial Oxford UKAs had a 15-year survival rate of 93%. Berger and colleagues⁴¹ reported similar numbers for the Miller-Galante prosthesis. Survival rates were 98% (10 years) and 95.7% (13 years), and 92% of patients had good to excellent Hospital for Special Surgery knee scores.

Although various modern implants have had good to excellent results, the historical question of what type of UKA to use (mobile or fixed-bearing) remains unanswered. To try to address it, Peersman and colleagues⁴² performed a systematic review of 44 papers (9463 knees). The 2 implant types had comparable revision rates. Another recent retrospective study tried to determine what is crucial for implant survival: implant design or surgeon experience.⁴³ The authors concluded that prosthetic component positioning is key. Other authors have reported high-volume centers are crucial for satisfactory UKA results and lower revision rates.^44-46

Results of these studies indicate that, where UKAs are being performed in volume, 10-year survivorship rates higher than 90% and good to excellent outcomes can be expected.

UKA vs HTO

Cohort studies that have directly compared the 2 treatment modalities are scarce, and most have been retrospective. In a prospective study, Stukenborg-Colsman and colleagues⁴⁷ randomized patients with medial compartment OA to undergo either CWHTO (32 patients) with a technique reported by Coventry⁴⁸ or UKA (28 patients) with the unicondylar knee sliding prosthesis, Tübingen pattern (Aesculap), between 1988 and 1991. Patients were assessed 2.5, 4.5, and 7.5 years after surgery. More postoperative complications were noted in the HTO group. At 7- to 10-year follow-up, 71% of the HTO group and 65% of the UKA group had excellent KSS. Mean ROM was 103° after UKA (range, 35°-140°) and 117° after HTO (range, 85°-135°) during the same assessment. Although differences were not significant, Kaplan-Meier survival analysis was 60% for HTO and 77% for UKA at 10 years. Results were not promising for the implants used, compared with other implants, but the authors concluded that, because of improvements in implant designs and image-guided techniques, better long-term success can be expected with UKA than with HTO.

In another prospective study, Börjesson and colleagues⁴⁹ evaluated pain during walking, ROM, British Orthopaedic Association (BOA) scores, and gait variables at 1- and 5-year follow-up. Patients with moderate medial OA (Ahlbäck¹⁴ grade I-III) were randomly selected to undergo CWHTO or UKA (Brigham, DePuy). There were no significant differences in BOA scores, ROM, or pain during walking between the 2 groups at 3 months, 1 year, and 5 years after surgery. Gait analysis showed a significant difference in favor of UKA only at 3 months after surgery. At 1- and 5-year follow-up, no significant differences were noted.

To clarify current ambiguities, Fu and colleagues⁵⁰ performed a systematic review of all (11) comparative studies. These studies had a total of 5840 (5081 UKA, 759 HTO) patients. Although ROM was significantly better for the HTO group than the UKA group, the UKA group had significantly better functional results. Walking after surgery was significantly faster for the UKA group. The authors suggested the difference might be attributed to the different postoperative regimens—HTO patients wore a whole-leg plaster cast for 6 weeks, and UKA patients were allowed immediate postoperative weight-bearing. Regarding rates of survival and complications, pooled data showed no significant differences. Despite these results, the authors acknowledged the limitation of available randomized clinical trials and the multiple techniques and implants used. We share their assertion that larger prospective controlled trials are needed. These are crucial to getting a definitive answer regarding which of the 2 treatment strategies should be used for isolated compartment OA.

Current Trends in Use of UKA and HTO

Evaluation of national registries and recent reports showed a global shift in use of both HTO and UKA. Despite the lack of national HTO registries, a few reports have described use of TKA, UKA, and HTO in Western populations over the past 2 decades. Using 1998-2007 data from the Swedish Knee Arthroplasty Register, W-Dahl and colleagues⁵¹ found a 3-fold increase in UKA use, whereas HTO use was halved over the same period. Niinimäki and colleagues⁵² reported similar findings with the Finnish National Hospital Discharge Register. They noted a steady 6.8% annual decrease in osteotomies, whereas UKA use increased sharply after the Oxford UKA was introduced (Phase 3; Biomet). These findings are consistent with several reports from North America. In their epidemiologic analysis covering the period 1985-1990, Wright and colleagues⁵³ found an 11% to 14% annual decrease in osteotomies among the elderly, compared with an annual decrease of only 3% to 4% among patients younger than 65 years. Nwachukwu and colleagues⁵⁴ recently compared UKA and HTO practice patterns between 2007 and 2011, using data from a large US private payer insurance database. They noted an annual growth rate of 4.7% in UKA use, compared with an annual 3.9% decrease in HTO use. Furthermore, based on their subgroup analysis, they speculated there was a demographic shift toward UKA, as opposed to TKA, particularly in older women. Bolognesi and colleagues⁵⁵ investigated further. Evaluating all Medicare beneficiaries who underwent knee arthroplasty in the United States between 2000 and 2009, they noted a 1.7-fold increase in TKA use and a 6.2-fold increase in UKA use. As there were no substantial changes in patient characteristics over that period, the authors hypothesized that a possible broadening of inclusion criteria may have led to the increased use of UKA.

There is a possible multifactorial explanation for the current global shift in favor of UKA. First, UKA was once a technically demanding procedure, but improved surgical techniques, image guidance, and robot assistance⁵⁶ have made it relatively less difficult. Second, UKA surgery is associated with lower reported perioperative morbidities.⁵⁷ We think these factors have contributed to the global trend of less HTO use and more UKA use in the treatment of unicompartmental OA.

Conclusion

The modern literature suggests the inclusion criteria for HTO have been well investigated and defined; the UKA criteria remain a matter of debate but seem to be expanding. Long-term survival results seem to favor UKA, though patient satisfaction with both procedures is good to excellent. The broadening range of inclusion criteria and consistent reports of durable outcomes, coupled with excellent patient satisfaction, likely explain the shift toward UKA in the treatment of isolated compartment degeneration.

Am J Orthop. 2016;45(6):E355-E361. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

An increasingly number of patients with symptomatic isolated medial unicompartmental knee osteoarthritis (OA) are too young and too functionally active to be ideal candidates for total knee arthroplasty (TKA). Isolated medial compartment OA occurs in 10% to 29.5% of all cases, whereas the isolated lateral variant is less common, with a reported incidence of 1% to 7%.^1,2 In 1961, Jackson and Waugh³ introduced the high tibial osteotomy (HTO) as a surgical treatment for single-compartment OA. This procedure is designed to increase the life span of articular cartilage by unloading and redistributing the mechanical forces over the nonaffected compartment. Unicompartmental knee arthroplasty (UKA) was introduced in the 1970s as an alternative to TKA or HTO for single-compartment OA.

Since the introduction of these methods, there has been debate about which patients are appropriate candidates for each procedure. Improved surgical techniques and implant designs have led surgeons to reexamine the selection criteria and contraindications for these procedures. Furthermore, given the increasing popularity and use of UKA, the question arises as to whether HTO still has a role in clinical practice in the surgical treatment of medial OA of the knee.

To clarify current ambiguities, we review the modern indications, subjective outcome scores, and survivorship results of UKA and HTO in the treatment of isolated medial compartment degeneration of the knee. In addition, in a thorough review of the literature, we evaluate global trends in the use of both methods.

High Tibial Osteotomy for Medial Compartment OA

Indications

Before the introduction of TKA and UKA for single-compartment OA, surgical management consisted of HTO. When the mechanical axis is slightly overcorrected, the medial compartment is decompressed, ensuring tissue viability and delaying progressive compartment degeneration.

Traditionally, HTO is indicated for young (age <60 years), normal-weight, active patients with radiographic single-compartment OA.⁶ The knee should be stable and have good range of motion (ROM; flexion >120°), and pain should be localized to the tibiofemoral joint line.

Over the past few decades, numerous authors have reported similar inclusion criteria, clarifying their definition. This definition should be further refined in order to optimize survivorship and clinical outcomes.

Confirming age as an inclusion criterion for HTO, Trieb and colleagues⁷ found that the risk of failure was significantly (P = .046) higher for HTO patients older than 65 years than for those younger than 65 years (relative risk, 1.5). This finding agrees with findings of other studies, which suggests that, in particular, young patients benefit from HTO.^8-11

Moreover, there is a clear relation between HTO survival and obesity. In a study of 159 CWHTOs, Akizuki and colleagues¹² reported that preoperative body mass index (BMI) higher than 27.5 kg/m² was a significant risk factor for early failure. Using BMI higher than 30 kg/m² as a threshold, Howells and colleagues⁹ found significantly inferior Knee Society Score (KSS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) results for the obese group 5 years after HTO.

Radiographic evidence of severe preoperative compartment degeneration has been associated with early conversion to TKA. Flecher and colleagues¹¹ and van Raaij and colleagues¹³ both concluded the best long-term survival grades are achieved in HTO patients with mild compartment OA (Ahlbäck^14 grade I). The question then becomes whether these patients should be treated nonoperatively instead.^15,16The literature supports strict adherence to inclusion criteria in the selection of a potential HTO candidate. Age, BMI, and the preoperative state of OA should be taken into account in order to optimize clinical outcome and survivorship results in patients about to undergo HTO.

Outcomes

Multiple authors have described or compared the midterm or long-term results of the various surgical HTO techniques. Howells and colleagues⁹ noted overall survival rates of 87% (5 years after CWHTO) and 79% (10 years after CWHTO). Over the 10-year postoperative period, there was significant deterioration in clinical outcome scores and survivorship. Others authors have had similar findings.^17-19 van Raaij and colleagues¹³ found that the 10-year probability of survival after CWHTO was 75%. In 455 patients who underwent lateral CWHTO, Hui and colleagues⁸ found that 5-year probability of survival was 95%, 10-year probability was 79%, and 15-year probability was 56%. Niinimäki and colleagues¹⁰ used the Finnish Arthroplasty Register to report HTO survivorship at a national level. Using conversion to TKA as a cutoff, they noted 5-year survivorship of 89% and 10-year survivorship of 73%. To our knowledge, 2 groups, both in Japan, have reported substantially higher 15-year survival rates: 90%¹² and 93%.²⁰ The authors acknowledged that their results were significantly better than in other countries and that Japanese lifestyle, culture, and body habitus therefore require further investigation. At this time, it is not possible to compare their results with Western results.

In an attempt to compare the different survival rates of the various HTO techniques, Schallberger and colleagues²¹ conducted a retrospective study of OWHTOs and CWHTOs. At median follow-up of 16.5 years, comparative survival rates showed a trend of deterioration. Although data were limited, there were no significant differences in survival or functional outcome between the 2 techniques. In a recent randomized clinical trial, Duivenvoorden and colleagues⁵ compared these techniques’ midterm results (mean follow-up, 6 years). Clinical outcomes were not significantly different. There were more complications in the OWHTO group and more conversions to TKA in the CWHTO group. Considering these results, the authors suggested OWHTO without autologous bone graft is the best HTO treatment strategy for medial gonarthritis with varus malalignment of <12°.

The HTO results noted in these studies show a similar deteriorating trend; expected 10-year survivorship is 75%. Although modern implants and surgical techniques are being used, evidence supporting use of one surgical HTO method over another is lacking.

UKA for Medial Compartment OA

Indications

Since it was first introduced in the 1970s, use of UKA for single-compartment OA has been a subject of debate. The high failure rates reported at the time raised skepticism about the new treatment.²² Kozinn and Scott²³ defined classic indications and contraindications. Indications included isolated medial or lateral compartment OA or osteonecrosis of the knee, age over 60 years, and weight under 82 kg. In addition, the angular deformity of the affected lower extremity had to be <15° and passively correctable to neutral at time of surgery. Last, the flexion contracture had to be <5°, and ideal ROM was 90°. Contraindications included high activity, age under 60 years, and inflammatory arthritis. Strict adherence led to improved implant survival and lower revision rates. Because of improved surgical techniques, modern implant designs, and accumulating experience with the procedure, the surgical indications for UKA have expanded. Exact thresholds for UKA inclusion, however, remain unclear.

The modern literature is overturning the traditional idea that UKA is not indicated for patients under age 60 years.²³ Using KSS, Thompson and colleagues²⁴ found that younger patients did better than older patients 2 years after UKA using various types of implants. Analyzing survivorship results, Heyse and colleagues²⁵ concluded that UKA can be successful in patients under age 60 years and reported a 15-year survivorship rate of 85.6% and excellent outcome scores. Other authors have had similar findings.^26-28

Evaluating the influence of weight, Thompson and colleagues²⁴ found obese patients did not have a higher revision rate but did have slower progression of improvement 2 years after UKA. Cavaignac and colleagues²⁹ concluded that, at minimum follow-up of 7 years (range, 7-22 years), weight did not influence UKA survivorship. Other authors^30-33 have found no significant influence of BMI on survival.

Reports on preoperative radiographic parameters that can potentially influence UKA results are limited. In 113 medial UKAs studied by Niinimäki and colleagues,³⁴ mild medial compartment degeneration, seen on preoperative radiographs, was associated with significantly higher failure rates. The authors concluded that other treatment options should be favored in the absence of severe isolated compartment OA.

Although the classic indications defined by Kozinn and Scott²³ have yielded good to excellent UKA results, improvements in implants and surgical techniques^35-38 have extended the criteria. The modern literature demonstrates that age and BMI should not be used as criteria for excluding UKA candidates. Radiographically, there should be significant isolated compartment degeneration in order to optimize patient-reported outcome and survivorship.

Outcomes

Improved implant designs and modern minimally invasive techniques have effected a change in outcome results and a renewed interest in implants. Over the past decade, multiple authors have described the various modern UKA implants and their survivorship. Reports published since UKA was introduced in the 1970s show a continual increase in implant survival. Koskinen and colleagues,³⁹ using Finnish Arthroplasty Register data on 1819 UKAs performed between 1985 and 2003, found 10-year survival rates of 81% for Oxford implants (Zimmer Biomet), 79% for Miller-Galante II (Zimmer Biomet), 78% for Duracon (Howmedica), and 53% for PCA unicompartmental knee (Howmedica). Heyse and colleagues²⁵ reported 10- and 15-year survivorship data (93.5% and 86.3%, respectively) for 223 patients under age 60 years at the time of their index surgery (Genesis Unicondylar implant, Smith & Nephew), performed between 1993 and 2005. KSS was good to excellent. Similar numbers in cohorts under age 60 years were reported by Schai and colleagues²⁶ using the PFC system (Johnson & Johnson) and by Price and colleagues²⁷ using the medial Oxford UKA. Both groups reported excellent survivorship rates: 93% at 2- to 6-year follow-up and 91% at 10-year follow-up. The outcome in older patients seems satisfactory as well. In another multicenter report, by Price and colleagues,⁴⁰ medial Oxford UKAs had a 15-year survival rate of 93%. Berger and colleagues⁴¹ reported similar numbers for the Miller-Galante prosthesis. Survival rates were 98% (10 years) and 95.7% (13 years), and 92% of patients had good to excellent Hospital for Special Surgery knee scores.

Although various modern implants have had good to excellent results, the historical question of what type of UKA to use (mobile or fixed-bearing) remains unanswered. To try to address it, Peersman and colleagues⁴² performed a systematic review of 44 papers (9463 knees). The 2 implant types had comparable revision rates. Another recent retrospective study tried to determine what is crucial for implant survival: implant design or surgeon experience.⁴³ The authors concluded that prosthetic component positioning is key. Other authors have reported high-volume centers are crucial for satisfactory UKA results and lower revision rates.^44-46

Results of these studies indicate that, where UKAs are being performed in volume, 10-year survivorship rates higher than 90% and good to excellent outcomes can be expected.

UKA vs HTO

Cohort studies that have directly compared the 2 treatment modalities are scarce, and most have been retrospective. In a prospective study, Stukenborg-Colsman and colleagues⁴⁷ randomized patients with medial compartment OA to undergo either CWHTO (32 patients) with a technique reported by Coventry⁴⁸ or UKA (28 patients) with the unicondylar knee sliding prosthesis, Tübingen pattern (Aesculap), between 1988 and 1991. Patients were assessed 2.5, 4.5, and 7.5 years after surgery. More postoperative complications were noted in the HTO group. At 7- to 10-year follow-up, 71% of the HTO group and 65% of the UKA group had excellent KSS. Mean ROM was 103° after UKA (range, 35°-140°) and 117° after HTO (range, 85°-135°) during the same assessment. Although differences were not significant, Kaplan-Meier survival analysis was 60% for HTO and 77% for UKA at 10 years. Results were not promising for the implants used, compared with other implants, but the authors concluded that, because of improvements in implant designs and image-guided techniques, better long-term success can be expected with UKA than with HTO.

In another prospective study, Börjesson and colleagues⁴⁹ evaluated pain during walking, ROM, British Orthopaedic Association (BOA) scores, and gait variables at 1- and 5-year follow-up. Patients with moderate medial OA (Ahlbäck¹⁴ grade I-III) were randomly selected to undergo CWHTO or UKA (Brigham, DePuy). There were no significant differences in BOA scores, ROM, or pain during walking between the 2 groups at 3 months, 1 year, and 5 years after surgery. Gait analysis showed a significant difference in favor of UKA only at 3 months after surgery. At 1- and 5-year follow-up, no significant differences were noted.

To clarify current ambiguities, Fu and colleagues⁵⁰ performed a systematic review of all (11) comparative studies. These studies had a total of 5840 (5081 UKA, 759 HTO) patients. Although ROM was significantly better for the HTO group than the UKA group, the UKA group had significantly better functional results. Walking after surgery was significantly faster for the UKA group. The authors suggested the difference might be attributed to the different postoperative regimens—HTO patients wore a whole-leg plaster cast for 6 weeks, and UKA patients were allowed immediate postoperative weight-bearing. Regarding rates of survival and complications, pooled data showed no significant differences. Despite these results, the authors acknowledged the limitation of available randomized clinical trials and the multiple techniques and implants used. We share their assertion that larger prospective controlled trials are needed. These are crucial to getting a definitive answer regarding which of the 2 treatment strategies should be used for isolated compartment OA.

Current Trends in Use of UKA and HTO

Evaluation of national registries and recent reports showed a global shift in use of both HTO and UKA. Despite the lack of national HTO registries, a few reports have described use of TKA, UKA, and HTO in Western populations over the past 2 decades. Using 1998-2007 data from the Swedish Knee Arthroplasty Register, W-Dahl and colleagues⁵¹ found a 3-fold increase in UKA use, whereas HTO use was halved over the same period. Niinimäki and colleagues⁵² reported similar findings with the Finnish National Hospital Discharge Register. They noted a steady 6.8% annual decrease in osteotomies, whereas UKA use increased sharply after the Oxford UKA was introduced (Phase 3; Biomet). These findings are consistent with several reports from North America. In their epidemiologic analysis covering the period 1985-1990, Wright and colleagues⁵³ found an 11% to 14% annual decrease in osteotomies among the elderly, compared with an annual decrease of only 3% to 4% among patients younger than 65 years. Nwachukwu and colleagues⁵⁴ recently compared UKA and HTO practice patterns between 2007 and 2011, using data from a large US private payer insurance database. They noted an annual growth rate of 4.7% in UKA use, compared with an annual 3.9% decrease in HTO use. Furthermore, based on their subgroup analysis, they speculated there was a demographic shift toward UKA, as opposed to TKA, particularly in older women. Bolognesi and colleagues⁵⁵ investigated further. Evaluating all Medicare beneficiaries who underwent knee arthroplasty in the United States between 2000 and 2009, they noted a 1.7-fold increase in TKA use and a 6.2-fold increase in UKA use. As there were no substantial changes in patient characteristics over that period, the authors hypothesized that a possible broadening of inclusion criteria may have led to the increased use of UKA.

There is a possible multifactorial explanation for the current global shift in favor of UKA. First, UKA was once a technically demanding procedure, but improved surgical techniques, image guidance, and robot assistance⁵⁶ have made it relatively less difficult. Second, UKA surgery is associated with lower reported perioperative morbidities.⁵⁷ We think these factors have contributed to the global trend of less HTO use and more UKA use in the treatment of unicompartmental OA.

Conclusion

The modern literature suggests the inclusion criteria for HTO have been well investigated and defined; the UKA criteria remain a matter of debate but seem to be expanding. Long-term survival results seem to favor UKA, though patient satisfaction with both procedures is good to excellent. The broadening range of inclusion criteria and consistent reports of durable outcomes, coupled with excellent patient satisfaction, likely explain the shift toward UKA in the treatment of isolated compartment degeneration.

Am J Orthop. 2016;45(6):E355-E361. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

Total hip arthroplasty (THA) has revolutionized the practice of orthopedic surgery. The number of primary THAs performed in the United States alone is predicted to rise to 572,000 per year by 2030.¹ Increasing demand requires a tighter focus on cost-effectiveness, particularly with regard to expensive postoperative complications. Trunnionosis and taper corrosion have recently emerged as problems in THA.^2-7 No longer restricted to metal-on-metal bearings, these phenomena now affect an increasing number of metal-on-polyethylene THAs and are exacerbated by modularity.⁸ The emergence of these complications adds complexity to the diagnostic algorithm in patients who present with painful THAs. Furthermore, the diagnosis of either trunnionosis or taper corrosion calls for revision surgery. In response to the increase in these complications, a group of orthopedic professional societies developed an algorithm for managing suspected metal toxicity issues.⁹ However, increases in toxicity and patient morbidity, and the added costs of toxicity surveillance and revision surgery, will place a substantial economic burden on many health systems at a time when policy makers are implementing substantial changes to health delivery in an effort to contain costs while improving patient outcomes.

Although they are more expensive than cobalt-chrome heads, ceramic femoral heads make metal toxicity a nonissue and eliminate the need for toxicity surveillance protocols. Furthermore, ceramic femoral heads are thought to have longevity advantages (this relationship needs to be confirmed in long-term studies).

In this article, we provide a theoretical framework for debating whether use of ceramic femoral heads in all THA patients could represent a more cost-effective option over the long term.

Materials and Methods

Guidelines for the diagnostic algorithm for painful THA with suspected metal toxicity were obtained from a recent orthopedic professional society consensus statement.⁹ The cost of this work-up was obtained from the finance department at our institution (Table 1).

We created 2 metrics to analyze the cost difference between ceramic and cobalt-chrome femoral heads. The first metric was “ceramic surplus,” the extra cost of a ceramic femoral head above that of a cobalt-chrome femoral head, and the second was “maximum ceramic surplus,” the ceramic surplus cutoff value for which using ceramic femoral heads in all patients becomes more cost-effective than using cobalt-chrome heads.

Results

A single metal toxicity work-up cost $5085 with MARS-MRI and $2402 with US (Table 1). Revision THA with a 3-day inpatient stay cost $53,320, and that figure does not include the cost of surgical implants or perioperative medications and devices, all of which have highly variable cost structures (Table 1). Ceramic surplus was as low as $500 in a high-volume academic practice and as high as $1500 in a low-volume private practice (Table 2). Maximum ceramic surplus ranged from $511 to $2044 in the models integrating MARS-MRI and from $488 to $1950 in the models integrating US (Table 3).

Discussion

Trunnionosis, corrosion, and metal toxicity are of increasing concern in hip implants that incorporate a cobalt-chrome femoral head, regardless of the counterpart articulation surface (metal, ceramic, polyethylene).^2-8 In response to the added diagnostic challenge raised by these phenomena, a group of orthopedic professional societies developed an algorithm that can guide surgeons in the management of suspected corrosion or metal toxicity.⁹ In this protocol, toxicity surveillance in conjunction with potential revision surgery for metal-associated complications has the potential to increase patient morbidity and place a significant economic burden on many health systems. Given the recent emergence of trunnionosis, epidemiologic data on this complication are lacking.¹⁰ However, there is a substantial body of evidence showing devastating complications associated with adverse reactions to metal debris.^11-17

Given the potential complications specific to cobalt-chrome femoral heads, we wanted to provide a theoretical framework for debating whether use of ceramic heads in all patients has the potential to be a more cost-effective option over the long term. Ceramic femoral heads are premium implants, certainly more expensive at initial point of care. One study based on a large community registry showed premium implants (eg, ceramic femoral heads) add a surplus averaging $1000.¹⁸ In our investigation, ceramic surplus varied with practice setting, from $500 to $1500. Lower costs were discovered in high-volume practice settings, indicating that a shift to increased use of ceramic femoral heads would likely decrease ceramic surplus for most institutions.

We used a series of simulations to predict maximum ceramic surplus after manipulation of theoretical incidence ratios. The main limitation of this study was our use of 7% as the incidence of painful THA within 1- to 2-year follow-up. This point estimate was derived from a manuscript that to our knowledge provides the most realistic estimate of this complication¹⁰; with use of more complete data in upcoming studies, however, the 7% figure could certainly change. As data are also lacking on the proportion of painful THAs that receive a metal work-up and on the proportion of metal work-ups that indicate revision surgery, we modeled values of 12.5%, 25%, and 50% for each of these metrics to cover a wide range of possibilities.

It is also true the model did not incorporate scenarios to account for the law of unintended consequences, which would caution that using ceramics for all patients may bring a new set of complications. Zirconia ceramic bearings have tended to fracture, with the vast majority of fractures occurring in the liner of ceramic-on-ceramic articulations. Midterm reports and laboratory data suggest this issue has largely been solved with the advent of delta ceramics, a composite containing only a small fraction of zirconia.^19,20 Nevertheless, longer term in vivo data are needed to confirm the stability, longevity, and complication profile of these materials.

A final limitation of the present study is that the cost of a single metal toxicity work-up was based on just one institution. Grossly differing cost structures in other markets could alter the economic risk–benefit analysis we have described. However, we should note that the costs of tests, procedures, and appointments at our institution were uniform across a wide variety of practice settings in multiple regions of the United States, and thus are likely similar to the costs at a majority of practices.

Although our model took some liberties by necessity, it was also quite conservative in many respects. Many patients who undergo surveillance for metal toxicity undergo serial follow-ups; for this analysis, however, we considered the cost of only a single work-up. In addition, our proposed cost of revision surgery accounts only for facility and personnel costs during a 3-day inpatient stay and does not include the costs of implants, perioperative medications and devices, follow-up care, and potentially longer hospital stays or subsequent procedures, all of which can be highly variable and add considerable cost. Had any or all of these factors been incorporated into more complex modeling, the potential economic benefits of ceramic femoral heads would have been significantly greater.

After taking all these factors into account, our model found that maximum ceramic surplus ranged from $488 to $2044, depending on theoretical incidence ratio and imaging modality (Table 3). The lowest maximum ceramic surplus values ($511 for MARS-MRI protocol, $488 for US protocol) were based on the assumption that only 12.5% of patients who present with a painful THA receive a single metal work-up (0.875% of all THAs) and that only 12.5% of those patients are eventually revised (0.11% of all THAs). This outcome suggests ceramic femoral heads could be more cost-effective than cobalt-chrome femoral heads under these conservative projections when considering ceramic surplus is already as low as $500 at some high-volume centers. This figure would likely decline further in parallel with widespread growth in demand. Further study on the epidemiology of trunnionosis, corrosion, and metal toxicity in metal-on-polyethylene THA is needed to evaluate the economic validity of this proposal. Nevertheless, the superior safety profile of ceramic femoral heads with regard to metal toxicity indicates that wholesale use in THAs may in fact provide the most economical option on a societal scale.

Am J Orthop. 2016;45(6):E362-E366. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

Total hip arthroplasty (THA) has revolutionized the practice of orthopedic surgery. The number of primary THAs performed in the United States alone is predicted to rise to 572,000 per year by 2030.¹ Increasing demand requires a tighter focus on cost-effectiveness, particularly with regard to expensive postoperative complications. Trunnionosis and taper corrosion have recently emerged as problems in THA.^2-7 No longer restricted to metal-on-metal bearings, these phenomena now affect an increasing number of metal-on-polyethylene THAs and are exacerbated by modularity.⁸ The emergence of these complications adds complexity to the diagnostic algorithm in patients who present with painful THAs. Furthermore, the diagnosis of either trunnionosis or taper corrosion calls for revision surgery. In response to the increase in these complications, a group of orthopedic professional societies developed an algorithm for managing suspected metal toxicity issues.⁹ However, increases in toxicity and patient morbidity, and the added costs of toxicity surveillance and revision surgery, will place a substantial economic burden on many health systems at a time when policy makers are implementing substantial changes to health delivery in an effort to contain costs while improving patient outcomes.

Although they are more expensive than cobalt-chrome heads, ceramic femoral heads make metal toxicity a nonissue and eliminate the need for toxicity surveillance protocols. Furthermore, ceramic femoral heads are thought to have longevity advantages (this relationship needs to be confirmed in long-term studies).

In this article, we provide a theoretical framework for debating whether use of ceramic femoral heads in all THA patients could represent a more cost-effective option over the long term.

Materials and Methods

Guidelines for the diagnostic algorithm for painful THA with suspected metal toxicity were obtained from a recent orthopedic professional society consensus statement.⁹ The cost of this work-up was obtained from the finance department at our institution (Table 1).

We created 2 metrics to analyze the cost difference between ceramic and cobalt-chrome femoral heads. The first metric was “ceramic surplus,” the extra cost of a ceramic femoral head above that of a cobalt-chrome femoral head, and the second was “maximum ceramic surplus,” the ceramic surplus cutoff value for which using ceramic femoral heads in all patients becomes more cost-effective than using cobalt-chrome heads.

Results

A single metal toxicity work-up cost $5085 with MARS-MRI and $2402 with US (Table 1). Revision THA with a 3-day inpatient stay cost $53,320, and that figure does not include the cost of surgical implants or perioperative medications and devices, all of which have highly variable cost structures (Table 1). Ceramic surplus was as low as $500 in a high-volume academic practice and as high as $1500 in a low-volume private practice (Table 2). Maximum ceramic surplus ranged from $511 to $2044 in the models integrating MARS-MRI and from $488 to $1950 in the models integrating US (Table 3).

Discussion

Trunnionosis, corrosion, and metal toxicity are of increasing concern in hip implants that incorporate a cobalt-chrome femoral head, regardless of the counterpart articulation surface (metal, ceramic, polyethylene).^2-8 In response to the added diagnostic challenge raised by these phenomena, a group of orthopedic professional societies developed an algorithm that can guide surgeons in the management of suspected corrosion or metal toxicity.⁹ In this protocol, toxicity surveillance in conjunction with potential revision surgery for metal-associated complications has the potential to increase patient morbidity and place a significant economic burden on many health systems. Given the recent emergence of trunnionosis, epidemiologic data on this complication are lacking.¹⁰ However, there is a substantial body of evidence showing devastating complications associated with adverse reactions to metal debris.^11-17

Given the potential complications specific to cobalt-chrome femoral heads, we wanted to provide a theoretical framework for debating whether use of ceramic heads in all patients has the potential to be a more cost-effective option over the long term. Ceramic femoral heads are premium implants, certainly more expensive at initial point of care. One study based on a large community registry showed premium implants (eg, ceramic femoral heads) add a surplus averaging $1000.¹⁸ In our investigation, ceramic surplus varied with practice setting, from $500 to $1500. Lower costs were discovered in high-volume practice settings, indicating that a shift to increased use of ceramic femoral heads would likely decrease ceramic surplus for most institutions.

We used a series of simulations to predict maximum ceramic surplus after manipulation of theoretical incidence ratios. The main limitation of this study was our use of 7% as the incidence of painful THA within 1- to 2-year follow-up. This point estimate was derived from a manuscript that to our knowledge provides the most realistic estimate of this complication¹⁰; with use of more complete data in upcoming studies, however, the 7% figure could certainly change. As data are also lacking on the proportion of painful THAs that receive a metal work-up and on the proportion of metal work-ups that indicate revision surgery, we modeled values of 12.5%, 25%, and 50% for each of these metrics to cover a wide range of possibilities.

It is also true the model did not incorporate scenarios to account for the law of unintended consequences, which would caution that using ceramics for all patients may bring a new set of complications. Zirconia ceramic bearings have tended to fracture, with the vast majority of fractures occurring in the liner of ceramic-on-ceramic articulations. Midterm reports and laboratory data suggest this issue has largely been solved with the advent of delta ceramics, a composite containing only a small fraction of zirconia.^19,20 Nevertheless, longer term in vivo data are needed to confirm the stability, longevity, and complication profile of these materials.

A final limitation of the present study is that the cost of a single metal toxicity work-up was based on just one institution. Grossly differing cost structures in other markets could alter the economic risk–benefit analysis we have described. However, we should note that the costs of tests, procedures, and appointments at our institution were uniform across a wide variety of practice settings in multiple regions of the United States, and thus are likely similar to the costs at a majority of practices.

Although our model took some liberties by necessity, it was also quite conservative in many respects. Many patients who undergo surveillance for metal toxicity undergo serial follow-ups; for this analysis, however, we considered the cost of only a single work-up. In addition, our proposed cost of revision surgery accounts only for facility and personnel costs during a 3-day inpatient stay and does not include the costs of implants, perioperative medications and devices, follow-up care, and potentially longer hospital stays or subsequent procedures, all of which can be highly variable and add considerable cost. Had any or all of these factors been incorporated into more complex modeling, the potential economic benefits of ceramic femoral heads would have been significantly greater.

After taking all these factors into account, our model found that maximum ceramic surplus ranged from $488 to $2044, depending on theoretical incidence ratio and imaging modality (Table 3). The lowest maximum ceramic surplus values ($511 for MARS-MRI protocol, $488 for US protocol) were based on the assumption that only 12.5% of patients who present with a painful THA receive a single metal work-up (0.875% of all THAs) and that only 12.5% of those patients are eventually revised (0.11% of all THAs). This outcome suggests ceramic femoral heads could be more cost-effective than cobalt-chrome femoral heads under these conservative projections when considering ceramic surplus is already as low as $500 at some high-volume centers. This figure would likely decline further in parallel with widespread growth in demand. Further study on the epidemiology of trunnionosis, corrosion, and metal toxicity in metal-on-polyethylene THA is needed to evaluate the economic validity of this proposal. Nevertheless, the superior safety profile of ceramic femoral heads with regard to metal toxicity indicates that wholesale use in THAs may in fact provide the most economical option on a societal scale.

Am J Orthop. 2016;45(6):E362-E366. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

Total hip arthroplasty (THA) has revolutionized the practice of orthopedic surgery. The number of primary THAs performed in the United States alone is predicted to rise to 572,000 per year by 2030.¹ Increasing demand requires a tighter focus on cost-effectiveness, particularly with regard to expensive postoperative complications. Trunnionosis and taper corrosion have recently emerged as problems in THA.^2-7 No longer restricted to metal-on-metal bearings, these phenomena now affect an increasing number of metal-on-polyethylene THAs and are exacerbated by modularity.⁸ The emergence of these complications adds complexity to the diagnostic algorithm in patients who present with painful THAs. Furthermore, the diagnosis of either trunnionosis or taper corrosion calls for revision surgery. In response to the increase in these complications, a group of orthopedic professional societies developed an algorithm for managing suspected metal toxicity issues.⁹ However, increases in toxicity and patient morbidity, and the added costs of toxicity surveillance and revision surgery, will place a substantial economic burden on many health systems at a time when policy makers are implementing substantial changes to health delivery in an effort to contain costs while improving patient outcomes.

Although they are more expensive than cobalt-chrome heads, ceramic femoral heads make metal toxicity a nonissue and eliminate the need for toxicity surveillance protocols. Furthermore, ceramic femoral heads are thought to have longevity advantages (this relationship needs to be confirmed in long-term studies).

In this article, we provide a theoretical framework for debating whether use of ceramic femoral heads in all THA patients could represent a more cost-effective option over the long term.

Materials and Methods

Guidelines for the diagnostic algorithm for painful THA with suspected metal toxicity were obtained from a recent orthopedic professional society consensus statement.⁹ The cost of this work-up was obtained from the finance department at our institution (Table 1).

We created 2 metrics to analyze the cost difference between ceramic and cobalt-chrome femoral heads. The first metric was “ceramic surplus,” the extra cost of a ceramic femoral head above that of a cobalt-chrome femoral head, and the second was “maximum ceramic surplus,” the ceramic surplus cutoff value for which using ceramic femoral heads in all patients becomes more cost-effective than using cobalt-chrome heads.

Results

A single metal toxicity work-up cost $5085 with MARS-MRI and $2402 with US (Table 1). Revision THA with a 3-day inpatient stay cost $53,320, and that figure does not include the cost of surgical implants or perioperative medications and devices, all of which have highly variable cost structures (Table 1). Ceramic surplus was as low as $500 in a high-volume academic practice and as high as $1500 in a low-volume private practice (Table 2). Maximum ceramic surplus ranged from $511 to $2044 in the models integrating MARS-MRI and from $488 to $1950 in the models integrating US (Table 3).

Discussion

Trunnionosis, corrosion, and metal toxicity are of increasing concern in hip implants that incorporate a cobalt-chrome femoral head, regardless of the counterpart articulation surface (metal, ceramic, polyethylene).^2-8 In response to the added diagnostic challenge raised by these phenomena, a group of orthopedic professional societies developed an algorithm that can guide surgeons in the management of suspected corrosion or metal toxicity.⁹ In this protocol, toxicity surveillance in conjunction with potential revision surgery for metal-associated complications has the potential to increase patient morbidity and place a significant economic burden on many health systems. Given the recent emergence of trunnionosis, epidemiologic data on this complication are lacking.¹⁰ However, there is a substantial body of evidence showing devastating complications associated with adverse reactions to metal debris.^11-17

Given the potential complications specific to cobalt-chrome femoral heads, we wanted to provide a theoretical framework for debating whether use of ceramic heads in all patients has the potential to be a more cost-effective option over the long term. Ceramic femoral heads are premium implants, certainly more expensive at initial point of care. One study based on a large community registry showed premium implants (eg, ceramic femoral heads) add a surplus averaging $1000.¹⁸ In our investigation, ceramic surplus varied with practice setting, from $500 to $1500. Lower costs were discovered in high-volume practice settings, indicating that a shift to increased use of ceramic femoral heads would likely decrease ceramic surplus for most institutions.

We used a series of simulations to predict maximum ceramic surplus after manipulation of theoretical incidence ratios. The main limitation of this study was our use of 7% as the incidence of painful THA within 1- to 2-year follow-up. This point estimate was derived from a manuscript that to our knowledge provides the most realistic estimate of this complication¹⁰; with use of more complete data in upcoming studies, however, the 7% figure could certainly change. As data are also lacking on the proportion of painful THAs that receive a metal work-up and on the proportion of metal work-ups that indicate revision surgery, we modeled values of 12.5%, 25%, and 50% for each of these metrics to cover a wide range of possibilities.

It is also true the model did not incorporate scenarios to account for the law of unintended consequences, which would caution that using ceramics for all patients may bring a new set of complications. Zirconia ceramic bearings have tended to fracture, with the vast majority of fractures occurring in the liner of ceramic-on-ceramic articulations. Midterm reports and laboratory data suggest this issue has largely been solved with the advent of delta ceramics, a composite containing only a small fraction of zirconia.^19,20 Nevertheless, longer term in vivo data are needed to confirm the stability, longevity, and complication profile of these materials.

A final limitation of the present study is that the cost of a single metal toxicity work-up was based on just one institution. Grossly differing cost structures in other markets could alter the economic risk–benefit analysis we have described. However, we should note that the costs of tests, procedures, and appointments at our institution were uniform across a wide variety of practice settings in multiple regions of the United States, and thus are likely similar to the costs at a majority of practices.

Although our model took some liberties by necessity, it was also quite conservative in many respects. Many patients who undergo surveillance for metal toxicity undergo serial follow-ups; for this analysis, however, we considered the cost of only a single work-up. In addition, our proposed cost of revision surgery accounts only for facility and personnel costs during a 3-day inpatient stay and does not include the costs of implants, perioperative medications and devices, follow-up care, and potentially longer hospital stays or subsequent procedures, all of which can be highly variable and add considerable cost. Had any or all of these factors been incorporated into more complex modeling, the potential economic benefits of ceramic femoral heads would have been significantly greater.

After taking all these factors into account, our model found that maximum ceramic surplus ranged from $488 to $2044, depending on theoretical incidence ratio and imaging modality (Table 3). The lowest maximum ceramic surplus values ($511 for MARS-MRI protocol, $488 for US protocol) were based on the assumption that only 12.5% of patients who present with a painful THA receive a single metal work-up (0.875% of all THAs) and that only 12.5% of those patients are eventually revised (0.11% of all THAs). This outcome suggests ceramic femoral heads could be more cost-effective than cobalt-chrome femoral heads under these conservative projections when considering ceramic surplus is already as low as $500 at some high-volume centers. This figure would likely decline further in parallel with widespread growth in demand. Further study on the epidemiology of trunnionosis, corrosion, and metal toxicity in metal-on-polyethylene THA is needed to evaluate the economic validity of this proposal. Nevertheless, the superior safety profile of ceramic femoral heads with regard to metal toxicity indicates that wholesale use in THAs may in fact provide the most economical option on a societal scale.

Am J Orthop. 2016;45(6):E362-E366. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

In both elective and revision surgery, removal of retained hardware can be unpredictable. Broken hardware, whether identified before or during surgery, presents a significant challenge. Cases often require enlisting a large variety of equipment and techniques that often result in larger dissection and potential for wider soft-tissue or bony destruction. Broken intramedullary devices, located entirely within the cortices of bone, pose unique challenges.^1,2 Various techniques have been used to remove broken cannulated nails.^1-9 There is, however, a paucity of techniques for removing broken solid nails from within the tibia.^1,2 Moreover, many of these techniques require significant metaphyseal and cortical bone destruction that may compromise the integrity of the long bone.^1,3,9 In this article, we describe a modified technique for removal of a broken solid nail, with minimal cortical bone destruction, in the setting of a tibial nonunion.

Technique

A 23-year-old man presented with a symptomatic valgus nonunion of the tibia, which had been treated with a solid intramedullary 9-mm nail (Orthofix). The patient was taken to the operative theater for nonunion takedown and exchanged reamed intramedullary nailing. The proximal fragment of the anterograde intramedullary nail was removed in standard fashion using the Winquist Universal Extraction Set (Shukla Medical). When threading the extractor into the proximal aspect of the nail, we found it helpful to leave one of the cross-locks in place to prevent nail rotation.¹⁰ Inspection of the removed nail revealed a fracture of the device at the more proximal of 2 distal cross-locks (Figures 1A, 1B, 2).

To remove the distal fragment of the nail, we used a 5.0-mm smooth Steinmann pin. After cross-lock removal, the pin was placed unicortically through the distal medial cortex at the tip of the retained implant. The distal nail fragment was pushed proximally using the pin as a lever with the interposed cortical bone serving as a fulcrum (Figures 3A, 3B).

Discussion

Removal of broken solid intramedullary tibial nails presents orthopedic surgeons with a unique challenge. We have described a technique that modifies and incorporates previously described techniques while exploiting available surgical windows to facilitate hardware removal. This technique obviates the need for further bony and soft-tissue dissection, potentially mitigating surgical morbidity.

Other techniques for removing broken solid intramedullary devices have been reported. Krettek and colleagues⁷ described a technique in which the short distal fragment of a broken solid femoral intramedullary nail was removed with use of retrograde levering through a cortical window just proximal to the articular surface. The same window was then used for anterograde nail removal with a small Hohmann retractor serving as a guide. This technique is limited by the need for a large bony window, which potentially creates a stress riser within the distal segment. In addition, a short, distal nail fragment is required in order to facilitate manipulation through the metaphyseal bone. This technique is more readily used within the distal femur, given the large metaphyseal volume, in contrast with the distal tibial metaphysis. Giannoudis and colleagues¹ described a method (for both tibia and femur) in which the intramedullary canal was proximally reamed to permit retrograde removal of an anterograde nail. The authors described reaming the canal to 4 mm larger than the nail to create access for a cleaning trephine and then a ratcheting extractor. This technique can be easily applied to the tibia or femur but requires special equipment that may not be readily available. Other retrograde techniques for the femur⁸ are not as suitable for the tibia, as they would cause significant chondral damage to the tibiotalar joint.

Am J Orthop. 2016;45(6):E352-E354. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

In both elective and revision surgery, removal of retained hardware can be unpredictable. Broken hardware, whether identified before or during surgery, presents a significant challenge. Cases often require enlisting a large variety of equipment and techniques that often result in larger dissection and potential for wider soft-tissue or bony destruction. Broken intramedullary devices, located entirely within the cortices of bone, pose unique challenges.^1,2 Various techniques have been used to remove broken cannulated nails.^1-9 There is, however, a paucity of techniques for removing broken solid nails from within the tibia.^1,2 Moreover, many of these techniques require significant metaphyseal and cortical bone destruction that may compromise the integrity of the long bone.^1,3,9 In this article, we describe a modified technique for removal of a broken solid nail, with minimal cortical bone destruction, in the setting of a tibial nonunion.

Technique

A 23-year-old man presented with a symptomatic valgus nonunion of the tibia, which had been treated with a solid intramedullary 9-mm nail (Orthofix). The patient was taken to the operative theater for nonunion takedown and exchanged reamed intramedullary nailing. The proximal fragment of the anterograde intramedullary nail was removed in standard fashion using the Winquist Universal Extraction Set (Shukla Medical). When threading the extractor into the proximal aspect of the nail, we found it helpful to leave one of the cross-locks in place to prevent nail rotation.¹⁰ Inspection of the removed nail revealed a fracture of the device at the more proximal of 2 distal cross-locks (Figures 1A, 1B, 2).

To remove the distal fragment of the nail, we used a 5.0-mm smooth Steinmann pin. After cross-lock removal, the pin was placed unicortically through the distal medial cortex at the tip of the retained implant. The distal nail fragment was pushed proximally using the pin as a lever with the interposed cortical bone serving as a fulcrum (Figures 3A, 3B).

Discussion

Removal of broken solid intramedullary tibial nails presents orthopedic surgeons with a unique challenge. We have described a technique that modifies and incorporates previously described techniques while exploiting available surgical windows to facilitate hardware removal. This technique obviates the need for further bony and soft-tissue dissection, potentially mitigating surgical morbidity.

Other techniques for removing broken solid intramedullary devices have been reported. Krettek and colleagues⁷ described a technique in which the short distal fragment of a broken solid femoral intramedullary nail was removed with use of retrograde levering through a cortical window just proximal to the articular surface. The same window was then used for anterograde nail removal with a small Hohmann retractor serving as a guide. This technique is limited by the need for a large bony window, which potentially creates a stress riser within the distal segment. In addition, a short, distal nail fragment is required in order to facilitate manipulation through the metaphyseal bone. This technique is more readily used within the distal femur, given the large metaphyseal volume, in contrast with the distal tibial metaphysis. Giannoudis and colleagues¹ described a method (for both tibia and femur) in which the intramedullary canal was proximally reamed to permit retrograde removal of an anterograde nail. The authors described reaming the canal to 4 mm larger than the nail to create access for a cleaning trephine and then a ratcheting extractor. This technique can be easily applied to the tibia or femur but requires special equipment that may not be readily available. Other retrograde techniques for the femur⁸ are not as suitable for the tibia, as they would cause significant chondral damage to the tibiotalar joint.

Am J Orthop. 2016;45(6):E352-E354. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

In both elective and revision surgery, removal of retained hardware can be unpredictable. Broken hardware, whether identified before or during surgery, presents a significant challenge. Cases often require enlisting a large variety of equipment and techniques that often result in larger dissection and potential for wider soft-tissue or bony destruction. Broken intramedullary devices, located entirely within the cortices of bone, pose unique challenges.^1,2 Various techniques have been used to remove broken cannulated nails.^1-9 There is, however, a paucity of techniques for removing broken solid nails from within the tibia.^1,2 Moreover, many of these techniques require significant metaphyseal and cortical bone destruction that may compromise the integrity of the long bone.^1,3,9 In this article, we describe a modified technique for removal of a broken solid nail, with minimal cortical bone destruction, in the setting of a tibial nonunion.

Technique

A 23-year-old man presented with a symptomatic valgus nonunion of the tibia, which had been treated with a solid intramedullary 9-mm nail (Orthofix). The patient was taken to the operative theater for nonunion takedown and exchanged reamed intramedullary nailing. The proximal fragment of the anterograde intramedullary nail was removed in standard fashion using the Winquist Universal Extraction Set (Shukla Medical). When threading the extractor into the proximal aspect of the nail, we found it helpful to leave one of the cross-locks in place to prevent nail rotation.¹⁰ Inspection of the removed nail revealed a fracture of the device at the more proximal of 2 distal cross-locks (Figures 1A, 1B, 2).

To remove the distal fragment of the nail, we used a 5.0-mm smooth Steinmann pin. After cross-lock removal, the pin was placed unicortically through the distal medial cortex at the tip of the retained implant. The distal nail fragment was pushed proximally using the pin as a lever with the interposed cortical bone serving as a fulcrum (Figures 3A, 3B).

Discussion

Removal of broken solid intramedullary tibial nails presents orthopedic surgeons with a unique challenge. We have described a technique that modifies and incorporates previously described techniques while exploiting available surgical windows to facilitate hardware removal. This technique obviates the need for further bony and soft-tissue dissection, potentially mitigating surgical morbidity.

Other techniques for removing broken solid intramedullary devices have been reported. Krettek and colleagues⁷ described a technique in which the short distal fragment of a broken solid femoral intramedullary nail was removed with use of retrograde levering through a cortical window just proximal to the articular surface. The same window was then used for anterograde nail removal with a small Hohmann retractor serving as a guide. This technique is limited by the need for a large bony window, which potentially creates a stress riser within the distal segment. In addition, a short, distal nail fragment is required in order to facilitate manipulation through the metaphyseal bone. This technique is more readily used within the distal femur, given the large metaphyseal volume, in contrast with the distal tibial metaphysis. Giannoudis and colleagues¹ described a method (for both tibia and femur) in which the intramedullary canal was proximally reamed to permit retrograde removal of an anterograde nail. The authors described reaming the canal to 4 mm larger than the nail to create access for a cleaning trephine and then a ratcheting extractor. This technique can be easily applied to the tibia or femur but requires special equipment that may not be readily available. Other retrograde techniques for the femur⁸ are not as suitable for the tibia, as they would cause significant chondral damage to the tibiotalar joint.

Am J Orthop. 2016;45(6):E352-E354. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.