Knee

BARCELONA – People with osteoarthritis who are going to need knee replacement have markedly more cartilage loss earlier in the course of their disease than do osteoarthritis patients who keep their knees, judging from an image biomarker validation study presented at the World Congress on Osteoarthritis.

The finding that early loss of cartilage thickness predicts the need for future knee replacement is clinically significant, because some of the disease-modifying osteoarthritis drugs (DMOADs) that are under development aim both to ease or eliminate pain and to provide structural benefit in order to stop or reverse the structural changes, said Dr. Felix Eckstein, chief of the institute of anatomy and musculoskeletal research at Paracelsus Medical University, Salzburg, Austria.

"It’s unknown whether the modifying effect on joint structures will also provide clinical benefit for patients. The FDA would not approve a drug that improves structure without clinical benefit," said Dr. Eckstein, the lead investigator of the study.

The data presented were drawn from the U.S.-based Osteoarthritis Initiative (OAI), a multicenter, 4-year observational study of men and women that was designed to help improve treatment of knee osteoarthritis. Dr. Eckstein and his colleagues investigated structural changes that were detected using magnetic resonance imaging and observed their relationship to knee replacement in the year after measuring cartilage thickness.

In all, the study involved 109 knees from participants in the OAI who had received knee replacements between study years 1 and 4. A matched control knee was selected for each knee replacement case from OAI participants with the same Kellgren-Lawrence grade (KLG) at baseline.

The primary end point biomarker was loss of cartilage thickness after 1 year (taken as a time point prior to knee replacement and 1 year earlier) for the central medial compartment. The secondary end point was loss of cartilage thickness in the total medial compartment.

Segmentation of the cartilage using sagittal 3D dual-echo in steady state with water excitation (DESSwe) MRI sequence (3 Tesla) images provided measures of cartilage thickness. The investigators evaluated measurements of 16 subregions.

Dr. Eckstein and his associates matched participants according to their baseline radiographic disease stage, and looked within these strata for differentiation between those cases that progress to knee replacement and those that do not. "The new approach of this study was that we did not look at cases versus the rest of the cohort that may have been at a far earlier disease stage. We know that people at later radiographic disease stages have more cartilage loss than earlier disease stages."

They found that participants who had received knee replacement had lost three times as much cartilage as controls. "There was a lot variability, but it still discriminates with an area under the curve [AUC] of 0.59 (P = .007), so it is a significant differentiation," said Dr. Eckstein.

Breakdown by radiographic disease strata showed that the most marked differentiation occurred at the early disease stages. The AUC for KLG 2 was 0.67 (P = .009), versus an AUC of 0.55 (P = .16) for KLG 3, and an AUC of 0.53 (P = .65) for KLG 4. "At KLG 2, we see a relatively large difference in cartilage loss," he added.

Dr. Eckstein used ordered values as exploratory end points. "Rather than looking at the same region in every participant, we looked at the one region in each participant that changed the most over 1 year. Ordered values allow us look at the magnitude of change where it occurs with a specific risk factor set and then measure and compare this quantitatively between participants," he said.

The results showed that if magnitude of change is investigated wherever that change occurs, then the findings are greater in patients who progress to knee replacement, Dr. Eckstein said. "The differentiation for that particular order value is greater than a regional-based measure."

Looking ahead to the potential use of cartilage loss as a biomarker in trials, Dr. Eckstein said that "we think longitudinal, quantitative measures of cartilage loss predict knee replacement, particularly at the early radiographic stages. These MRI measures may be used in clinical trials to demonstrate the efficacy of DMOADs, with the large likelihood that these will translate into clinical benefits too."

The findings also lend support to the concept that treatments that slow cartilage loss may delay or prevent knee replacement. "We think that if a drug could reduce the cartilage loss, then this would also reduce the risk of knee replacement, because we’ve shown there is a link between cartilage loss and knee replacement," summarized Dr. Eckstein.

The meeting was sponsored by the Osteoarthritis Research Society International.

Dr. Eckstein reported ties with Medtronic, Merck Serono, Novartis, Perceptive, Pfizer, Sanofi-Aventis, and Synthes. He founded Chondrometrics in 2003. The study was funded by OAI, a public-private partnership of Novartis Pharma; the University of Pittsburgh’s Pivotal OAI MRI Analyses (POMA) study; the University of California, San Francisco; and the National Institutes of Health.

BARCELONA – People with osteoarthritis who are going to need knee replacement have markedly more cartilage loss earlier in the course of their disease than do osteoarthritis patients who keep their knees, judging from an image biomarker validation study presented at the World Congress on Osteoarthritis.

The finding that early loss of cartilage thickness predicts the need for future knee replacement is clinically significant, because some of the disease-modifying osteoarthritis drugs (DMOADs) that are under development aim both to ease or eliminate pain and to provide structural benefit in order to stop or reverse the structural changes, said Dr. Felix Eckstein, chief of the institute of anatomy and musculoskeletal research at Paracelsus Medical University, Salzburg, Austria.

"It’s unknown whether the modifying effect on joint structures will also provide clinical benefit for patients. The FDA would not approve a drug that improves structure without clinical benefit," said Dr. Eckstein, the lead investigator of the study.

The data presented were drawn from the U.S.-based Osteoarthritis Initiative (OAI), a multicenter, 4-year observational study of men and women that was designed to help improve treatment of knee osteoarthritis. Dr. Eckstein and his colleagues investigated structural changes that were detected using magnetic resonance imaging and observed their relationship to knee replacement in the year after measuring cartilage thickness.

In all, the study involved 109 knees from participants in the OAI who had received knee replacements between study years 1 and 4. A matched control knee was selected for each knee replacement case from OAI participants with the same Kellgren-Lawrence grade (KLG) at baseline.

The primary end point biomarker was loss of cartilage thickness after 1 year (taken as a time point prior to knee replacement and 1 year earlier) for the central medial compartment. The secondary end point was loss of cartilage thickness in the total medial compartment.

Segmentation of the cartilage using sagittal 3D dual-echo in steady state with water excitation (DESSwe) MRI sequence (3 Tesla) images provided measures of cartilage thickness. The investigators evaluated measurements of 16 subregions.

Dr. Eckstein and his associates matched participants according to their baseline radiographic disease stage, and looked within these strata for differentiation between those cases that progress to knee replacement and those that do not. "The new approach of this study was that we did not look at cases versus the rest of the cohort that may have been at a far earlier disease stage. We know that people at later radiographic disease stages have more cartilage loss than earlier disease stages."

They found that participants who had received knee replacement had lost three times as much cartilage as controls. "There was a lot variability, but it still discriminates with an area under the curve [AUC] of 0.59 (P = .007), so it is a significant differentiation," said Dr. Eckstein.

Breakdown by radiographic disease strata showed that the most marked differentiation occurred at the early disease stages. The AUC for KLG 2 was 0.67 (P = .009), versus an AUC of 0.55 (P = .16) for KLG 3, and an AUC of 0.53 (P = .65) for KLG 4. "At KLG 2, we see a relatively large difference in cartilage loss," he added.

Dr. Eckstein used ordered values as exploratory end points. "Rather than looking at the same region in every participant, we looked at the one region in each participant that changed the most over 1 year. Ordered values allow us look at the magnitude of change where it occurs with a specific risk factor set and then measure and compare this quantitatively between participants," he said.

The results showed that if magnitude of change is investigated wherever that change occurs, then the findings are greater in patients who progress to knee replacement, Dr. Eckstein said. "The differentiation for that particular order value is greater than a regional-based measure."

Looking ahead to the potential use of cartilage loss as a biomarker in trials, Dr. Eckstein said that "we think longitudinal, quantitative measures of cartilage loss predict knee replacement, particularly at the early radiographic stages. These MRI measures may be used in clinical trials to demonstrate the efficacy of DMOADs, with the large likelihood that these will translate into clinical benefits too."

The findings also lend support to the concept that treatments that slow cartilage loss may delay or prevent knee replacement. "We think that if a drug could reduce the cartilage loss, then this would also reduce the risk of knee replacement, because we’ve shown there is a link between cartilage loss and knee replacement," summarized Dr. Eckstein.

The meeting was sponsored by the Osteoarthritis Research Society International.

Dr. Eckstein reported ties with Medtronic, Merck Serono, Novartis, Perceptive, Pfizer, Sanofi-Aventis, and Synthes. He founded Chondrometrics in 2003. The study was funded by OAI, a public-private partnership of Novartis Pharma; the University of Pittsburgh’s Pivotal OAI MRI Analyses (POMA) study; the University of California, San Francisco; and the National Institutes of Health.

BARCELONA – People with osteoarthritis who are going to need knee replacement have markedly more cartilage loss earlier in the course of their disease than do osteoarthritis patients who keep their knees, judging from an image biomarker validation study presented at the World Congress on Osteoarthritis.

The finding that early loss of cartilage thickness predicts the need for future knee replacement is clinically significant, because some of the disease-modifying osteoarthritis drugs (DMOADs) that are under development aim both to ease or eliminate pain and to provide structural benefit in order to stop or reverse the structural changes, said Dr. Felix Eckstein, chief of the institute of anatomy and musculoskeletal research at Paracelsus Medical University, Salzburg, Austria.

"It’s unknown whether the modifying effect on joint structures will also provide clinical benefit for patients. The FDA would not approve a drug that improves structure without clinical benefit," said Dr. Eckstein, the lead investigator of the study.

The data presented were drawn from the U.S.-based Osteoarthritis Initiative (OAI), a multicenter, 4-year observational study of men and women that was designed to help improve treatment of knee osteoarthritis. Dr. Eckstein and his colleagues investigated structural changes that were detected using magnetic resonance imaging and observed their relationship to knee replacement in the year after measuring cartilage thickness.

In all, the study involved 109 knees from participants in the OAI who had received knee replacements between study years 1 and 4. A matched control knee was selected for each knee replacement case from OAI participants with the same Kellgren-Lawrence grade (KLG) at baseline.

The primary end point biomarker was loss of cartilage thickness after 1 year (taken as a time point prior to knee replacement and 1 year earlier) for the central medial compartment. The secondary end point was loss of cartilage thickness in the total medial compartment.

Segmentation of the cartilage using sagittal 3D dual-echo in steady state with water excitation (DESSwe) MRI sequence (3 Tesla) images provided measures of cartilage thickness. The investigators evaluated measurements of 16 subregions.

Dr. Eckstein and his associates matched participants according to their baseline radiographic disease stage, and looked within these strata for differentiation between those cases that progress to knee replacement and those that do not. "The new approach of this study was that we did not look at cases versus the rest of the cohort that may have been at a far earlier disease stage. We know that people at later radiographic disease stages have more cartilage loss than earlier disease stages."

They found that participants who had received knee replacement had lost three times as much cartilage as controls. "There was a lot variability, but it still discriminates with an area under the curve [AUC] of 0.59 (P = .007), so it is a significant differentiation," said Dr. Eckstein.

Breakdown by radiographic disease strata showed that the most marked differentiation occurred at the early disease stages. The AUC for KLG 2 was 0.67 (P = .009), versus an AUC of 0.55 (P = .16) for KLG 3, and an AUC of 0.53 (P = .65) for KLG 4. "At KLG 2, we see a relatively large difference in cartilage loss," he added.

Dr. Eckstein used ordered values as exploratory end points. "Rather than looking at the same region in every participant, we looked at the one region in each participant that changed the most over 1 year. Ordered values allow us look at the magnitude of change where it occurs with a specific risk factor set and then measure and compare this quantitatively between participants," he said.

The results showed that if magnitude of change is investigated wherever that change occurs, then the findings are greater in patients who progress to knee replacement, Dr. Eckstein said. "The differentiation for that particular order value is greater than a regional-based measure."

Looking ahead to the potential use of cartilage loss as a biomarker in trials, Dr. Eckstein said that "we think longitudinal, quantitative measures of cartilage loss predict knee replacement, particularly at the early radiographic stages. These MRI measures may be used in clinical trials to demonstrate the efficacy of DMOADs, with the large likelihood that these will translate into clinical benefits too."

The findings also lend support to the concept that treatments that slow cartilage loss may delay or prevent knee replacement. "We think that if a drug could reduce the cartilage loss, then this would also reduce the risk of knee replacement, because we’ve shown there is a link between cartilage loss and knee replacement," summarized Dr. Eckstein.

The meeting was sponsored by the Osteoarthritis Research Society International.

Dr. Eckstein reported ties with Medtronic, Merck Serono, Novartis, Perceptive, Pfizer, Sanofi-Aventis, and Synthes. He founded Chondrometrics in 2003. The study was funded by OAI, a public-private partnership of Novartis Pharma; the University of Pittsburgh’s Pivotal OAI MRI Analyses (POMA) study; the University of California, San Francisco; and the National Institutes of Health.

The incidence of total knee arthroplasties increased from 0.5 operations per 100,000 inhabitants to 65 operations per 100,000 inhabitants aged 30-59 years during 1980-2006 in patients with primary knee osteoarthritis, according to a Finnish study.

Patients born shortly after World War II showed the most dramatic increases.

Incidences of unicondylar or partial knee arthroplasties (UKAs) were also found to grow from 0.2 operations per 100,000 inhabitants to 10 operations per 100,000 inhabitants over the same period in the same Finnish patient age group.

"This phenomenon has been especially strong during the 21st century. There is no single explanatory factor for this growth. Some of the increase in incidence can be explained by hospital volume," wrote Dr. Jarkko Leskinen, Consultant Orthopedic Surgeon, Peijas Hospital, Helsinki University Central Hospital, who was lead author of the study published in the January issue of Arthritis & Rheumatism (Arthritis Rheum. 2012;64:423-8).

"The demand for primary TKA [total knee arthroplasty] has been estimated to grow by 673 percent to 3.48 million procedures in the United States by the year 2030," reported Dr. Leskinen. Previous studies reported increases in the incidence of TKA in younger patients in Australia and the United States in the 1980s and 1990s. This study aimed to analyze the changes in age group as well as the sex-standardized incidence of UKAs and TKAs in Finland between the years 1980 and 2006.

Patient data were drawn from the Finnish Arthroplasty Registry, and population data were obtained from Statistics Finland. A total of 8,961 knee arthroplasties were performed for primary osteoarthritis in patients under age 60 during 1980-2006. In addition to evaluating the effects of age and gender on the incidences of knee arthroplasties, Dr. Leskinen and his colleagues evaluated the effects of hospital volume.

Overall, the incidence rate ratio (IRR) for the annual increase in general incidence of UKAs was lower than that of TKAs, with an IRR of 1.26 for UKAs (95% confidence interval, 1.24-1.28; P less than .001) and 6.92 for TKAs (95% CI, 6.50-7.36; P less than .001).

In particular, the study found that the TKA incidence rose sharply from 18 per 100,000 in 2001 to 65 per 100,000 in 2006. TKAs were performed more often in women than men, with a 1.6- to 2.4-fold higher incidence in women than men during the past 10 years. Since 2000, a greater number of UKAs also were performed in women than men. Most of the increased incidence in TKAs and UKAs was in women aged 50-59 years.

Regarding the incidence of TKAs by age group, patients aged 50-59 years showed the largest increase, from 1.5 TKAs per 100,000 in 1980 to 160 per 100,000 in 2006. Incidences of UKAs by age group showed a similar pattern to TKAs, with the most marked growth in patients aged 50-59 years, increasing from 0.5 to 24 operations per 100,000. Growth was most rapid after the year 2000.

"Possible explanations for this phenomenon include the high functional and quality of life demands of younger patients aged less than 60 years," the authors wrote. "Another reason could be that the baby boomers may opt for elective operations at an earlier stage with milder symptoms, than the situation that was faced by earlier generations."

Hospitals were divided into low-, intermediate-, and high-volume centers, according to the number of TKAs performed in all the hospitals in Finland in 2006. The incidence of TKAs grew more rapidly in low- and intermediate-volume hospitals, while the incidence of UKAs grew in low-volume hospitals. The IRR for TKAs was 1.23 in both comparisons of low- to high-volume centers (95% CI, 1.13-1.34; P less than .001), and intermediate- to high-volume centers (95%CI, 1.16-1.31; P less than .001).

The authors warned against the widespread use of TKAs in younger patients. "Long-term results in young patients may differ from those reported in older patients, and risk for revision may be higher," they concluded.

Dr. Leskinen and his colleagues reported having no financial disclosures.

The incidence of total knee arthroplasties increased from 0.5 operations per 100,000 inhabitants to 65 operations per 100,000 inhabitants aged 30-59 years during 1980-2006 in patients with primary knee osteoarthritis, according to a Finnish study.

Patients born shortly after World War II showed the most dramatic increases.

Incidences of unicondylar or partial knee arthroplasties (UKAs) were also found to grow from 0.2 operations per 100,000 inhabitants to 10 operations per 100,000 inhabitants over the same period in the same Finnish patient age group.

"This phenomenon has been especially strong during the 21st century. There is no single explanatory factor for this growth. Some of the increase in incidence can be explained by hospital volume," wrote Dr. Jarkko Leskinen, Consultant Orthopedic Surgeon, Peijas Hospital, Helsinki University Central Hospital, who was lead author of the study published in the January issue of Arthritis & Rheumatism (Arthritis Rheum. 2012;64:423-8).

"The demand for primary TKA [total knee arthroplasty] has been estimated to grow by 673 percent to 3.48 million procedures in the United States by the year 2030," reported Dr. Leskinen. Previous studies reported increases in the incidence of TKA in younger patients in Australia and the United States in the 1980s and 1990s. This study aimed to analyze the changes in age group as well as the sex-standardized incidence of UKAs and TKAs in Finland between the years 1980 and 2006.

Patient data were drawn from the Finnish Arthroplasty Registry, and population data were obtained from Statistics Finland. A total of 8,961 knee arthroplasties were performed for primary osteoarthritis in patients under age 60 during 1980-2006. In addition to evaluating the effects of age and gender on the incidences of knee arthroplasties, Dr. Leskinen and his colleagues evaluated the effects of hospital volume.

Overall, the incidence rate ratio (IRR) for the annual increase in general incidence of UKAs was lower than that of TKAs, with an IRR of 1.26 for UKAs (95% confidence interval, 1.24-1.28; P less than .001) and 6.92 for TKAs (95% CI, 6.50-7.36; P less than .001).

In particular, the study found that the TKA incidence rose sharply from 18 per 100,000 in 2001 to 65 per 100,000 in 2006. TKAs were performed more often in women than men, with a 1.6- to 2.4-fold higher incidence in women than men during the past 10 years. Since 2000, a greater number of UKAs also were performed in women than men. Most of the increased incidence in TKAs and UKAs was in women aged 50-59 years.

Regarding the incidence of TKAs by age group, patients aged 50-59 years showed the largest increase, from 1.5 TKAs per 100,000 in 1980 to 160 per 100,000 in 2006. Incidences of UKAs by age group showed a similar pattern to TKAs, with the most marked growth in patients aged 50-59 years, increasing from 0.5 to 24 operations per 100,000. Growth was most rapid after the year 2000.

"Possible explanations for this phenomenon include the high functional and quality of life demands of younger patients aged less than 60 years," the authors wrote. "Another reason could be that the baby boomers may opt for elective operations at an earlier stage with milder symptoms, than the situation that was faced by earlier generations."

Hospitals were divided into low-, intermediate-, and high-volume centers, according to the number of TKAs performed in all the hospitals in Finland in 2006. The incidence of TKAs grew more rapidly in low- and intermediate-volume hospitals, while the incidence of UKAs grew in low-volume hospitals. The IRR for TKAs was 1.23 in both comparisons of low- to high-volume centers (95% CI, 1.13-1.34; P less than .001), and intermediate- to high-volume centers (95%CI, 1.16-1.31; P less than .001).

The authors warned against the widespread use of TKAs in younger patients. "Long-term results in young patients may differ from those reported in older patients, and risk for revision may be higher," they concluded.

Dr. Leskinen and his colleagues reported having no financial disclosures.

The incidence of total knee arthroplasties increased from 0.5 operations per 100,000 inhabitants to 65 operations per 100,000 inhabitants aged 30-59 years during 1980-2006 in patients with primary knee osteoarthritis, according to a Finnish study.

Patients born shortly after World War II showed the most dramatic increases.

Incidences of unicondylar or partial knee arthroplasties (UKAs) were also found to grow from 0.2 operations per 100,000 inhabitants to 10 operations per 100,000 inhabitants over the same period in the same Finnish patient age group.

"This phenomenon has been especially strong during the 21st century. There is no single explanatory factor for this growth. Some of the increase in incidence can be explained by hospital volume," wrote Dr. Jarkko Leskinen, Consultant Orthopedic Surgeon, Peijas Hospital, Helsinki University Central Hospital, who was lead author of the study published in the January issue of Arthritis & Rheumatism (Arthritis Rheum. 2012;64:423-8).

"The demand for primary TKA [total knee arthroplasty] has been estimated to grow by 673 percent to 3.48 million procedures in the United States by the year 2030," reported Dr. Leskinen. Previous studies reported increases in the incidence of TKA in younger patients in Australia and the United States in the 1980s and 1990s. This study aimed to analyze the changes in age group as well as the sex-standardized incidence of UKAs and TKAs in Finland between the years 1980 and 2006.

Patient data were drawn from the Finnish Arthroplasty Registry, and population data were obtained from Statistics Finland. A total of 8,961 knee arthroplasties were performed for primary osteoarthritis in patients under age 60 during 1980-2006. In addition to evaluating the effects of age and gender on the incidences of knee arthroplasties, Dr. Leskinen and his colleagues evaluated the effects of hospital volume.

Overall, the incidence rate ratio (IRR) for the annual increase in general incidence of UKAs was lower than that of TKAs, with an IRR of 1.26 for UKAs (95% confidence interval, 1.24-1.28; P less than .001) and 6.92 for TKAs (95% CI, 6.50-7.36; P less than .001).

In particular, the study found that the TKA incidence rose sharply from 18 per 100,000 in 2001 to 65 per 100,000 in 2006. TKAs were performed more often in women than men, with a 1.6- to 2.4-fold higher incidence in women than men during the past 10 years. Since 2000, a greater number of UKAs also were performed in women than men. Most of the increased incidence in TKAs and UKAs was in women aged 50-59 years.

Regarding the incidence of TKAs by age group, patients aged 50-59 years showed the largest increase, from 1.5 TKAs per 100,000 in 1980 to 160 per 100,000 in 2006. Incidences of UKAs by age group showed a similar pattern to TKAs, with the most marked growth in patients aged 50-59 years, increasing from 0.5 to 24 operations per 100,000. Growth was most rapid after the year 2000.

"Possible explanations for this phenomenon include the high functional and quality of life demands of younger patients aged less than 60 years," the authors wrote. "Another reason could be that the baby boomers may opt for elective operations at an earlier stage with milder symptoms, than the situation that was faced by earlier generations."

Hospitals were divided into low-, intermediate-, and high-volume centers, according to the number of TKAs performed in all the hospitals in Finland in 2006. The incidence of TKAs grew more rapidly in low- and intermediate-volume hospitals, while the incidence of UKAs grew in low-volume hospitals. The IRR for TKAs was 1.23 in both comparisons of low- to high-volume centers (95% CI, 1.13-1.34; P less than .001), and intermediate- to high-volume centers (95%CI, 1.16-1.31; P less than .001).

The authors warned against the widespread use of TKAs in younger patients. "Long-term results in young patients may differ from those reported in older patients, and risk for revision may be higher," they concluded.

Dr. Leskinen and his colleagues reported having no financial disclosures.

For the first time, researchers say they have established benchmarks for the rates of in-hospital venous thromboembolism that occur after total or partial hip arthroplasty and after total or partial knee arthroplasty, according to a report Jan. 18 in JAMA.

In a meta-analysis of 47 studies that documented venous thromboembolism (VTE) event rates in nearly 45,000 patients who received recommended prophylaxis during hospitalization for knee or hip arthroplasty, investigators estimated that approximately 1 in every 100 patients undergoing knee arthroplasty and 1 in every 200 undergoing hip arthroplasty will develop symptomatic VTE before they are discharged.

"These estimates are of value to individual patients and clinicians in the consideration of risks and benefits" of the two procedures. They also are important because rates of in-hospital VTE are increasingly used as indicators of patient safety at individual medical centers, even though the expected background rates haven’t been established until now, said Jean-Marie Januel, a registered nurse with the Institute of Social and Preventive Medicine, Lausanne (Switzerland) University Hospital, and his associates.

"Large numbers of patients worldwide undergo hip and knee replacement procedures annually, and VTE is a widely acknowledged complication. Yet no estimate of symptomatic VTE risk prior to hospital discharge is available from the literature that can be conveyed to patients in the informed consent process," they noted.

Mr. Januel and his colleagues performed a systemic search of the literature to identify studies performed between 1996 and 2011 in which subjects undergoing either hip or knee arthroplasty received VTE prophylaxis according to published guidelines, including either low-molecular-weight heparin or inhibitors of factor Xa or IIa. They found 41 randomized clinical trials and 6 observational studies to include in the meta-analysis.

A total of 22 of the studies were performed in Europe, 14 were in North America, and 11 were in other regions. The mean duration of follow-up after either surgery was 13 days.

This included 21 studies of partial or total hip arthroplasty, 20 of partial or total knee arthroplasty, and 6 studies of both procedures, with a total of 44,844 subjects.

There were 443 cases of symptomatic postoperative VTE that developed before hospital discharge: 288 in the 23,475 knee patients and 155 in the 23,475 hip patients. This included 182 cases of deep vein thrombosis in the knee patients and 93 in the hip patients, as well as 106 cases of pulmonary embolism in the knee patients and 43 in the hip patients.

The pooled incidence rates of VTE were approximately 1% after knee arthroplasty and approximately 0.5% after hip arthroplasty. This means that the background rate of VTE is approximately 1 in 100 knee patients and 1 in 200 hip patients, the investigators said (JAMA 2012;307:294-303).

When the data were broken down by type of VTE, the pooled incidence rates were 0.26% for deep vein thrombosis and 0.14% for pulmonary embolism after knee arthroplasty. The corresponding rates were 0.63% for deep vein thrombosis and 0.27% for pulmonary embolism after hip arthroplasty.

"Given that these rates are based on the results of rigorous studies, they may represent a lower incidence than actual rates observed in clinical practice, in which patients are selected less rigorously and prophylaxis is administered less assiduously," Mr. Januel and his associates noted.

The pooled incidence rates of deep vein thrombosis were lower for both knee patients and hip patients when factor Xa or IIa inhibitors, rather than low-molecular-weight heparin, were given for prophylaxis. "However, we cannot make assertions regarding comparative efficacy among treatments, because our meta-analysis did not directly compare [these agents] as an efficacy meta-analysis would have done," they said.

This study was supported by Alberta Innovates Health Solutions, a government research funding agency, and the International Methodology Consortium for Coded Health Information, a collaboration of health sciences researchers to promote quality of care. Dr. Heit reported ties to Daiichi Sankyo, GTC, Ortho-McNeil-Jansen, the National Heart, Lung, and Blood Institute, the National Human Genome Research Institute, the National Institutes of Health, the Centers for Disease Control and Prevention, and the Mayo Foundation.

For the first time, researchers say they have established benchmarks for the rates of in-hospital venous thromboembolism that occur after total or partial hip arthroplasty and after total or partial knee arthroplasty, according to a report Jan. 18 in JAMA.

In a meta-analysis of 47 studies that documented venous thromboembolism (VTE) event rates in nearly 45,000 patients who received recommended prophylaxis during hospitalization for knee or hip arthroplasty, investigators estimated that approximately 1 in every 100 patients undergoing knee arthroplasty and 1 in every 200 undergoing hip arthroplasty will develop symptomatic VTE before they are discharged.

"These estimates are of value to individual patients and clinicians in the consideration of risks and benefits" of the two procedures. They also are important because rates of in-hospital VTE are increasingly used as indicators of patient safety at individual medical centers, even though the expected background rates haven’t been established until now, said Jean-Marie Januel, a registered nurse with the Institute of Social and Preventive Medicine, Lausanne (Switzerland) University Hospital, and his associates.

"Large numbers of patients worldwide undergo hip and knee replacement procedures annually, and VTE is a widely acknowledged complication. Yet no estimate of symptomatic VTE risk prior to hospital discharge is available from the literature that can be conveyed to patients in the informed consent process," they noted.

Mr. Januel and his colleagues performed a systemic search of the literature to identify studies performed between 1996 and 2011 in which subjects undergoing either hip or knee arthroplasty received VTE prophylaxis according to published guidelines, including either low-molecular-weight heparin or inhibitors of factor Xa or IIa. They found 41 randomized clinical trials and 6 observational studies to include in the meta-analysis.

A total of 22 of the studies were performed in Europe, 14 were in North America, and 11 were in other regions. The mean duration of follow-up after either surgery was 13 days.

This included 21 studies of partial or total hip arthroplasty, 20 of partial or total knee arthroplasty, and 6 studies of both procedures, with a total of 44,844 subjects.

There were 443 cases of symptomatic postoperative VTE that developed before hospital discharge: 288 in the 23,475 knee patients and 155 in the 23,475 hip patients. This included 182 cases of deep vein thrombosis in the knee patients and 93 in the hip patients, as well as 106 cases of pulmonary embolism in the knee patients and 43 in the hip patients.

The pooled incidence rates of VTE were approximately 1% after knee arthroplasty and approximately 0.5% after hip arthroplasty. This means that the background rate of VTE is approximately 1 in 100 knee patients and 1 in 200 hip patients, the investigators said (JAMA 2012;307:294-303).

When the data were broken down by type of VTE, the pooled incidence rates were 0.26% for deep vein thrombosis and 0.14% for pulmonary embolism after knee arthroplasty. The corresponding rates were 0.63% for deep vein thrombosis and 0.27% for pulmonary embolism after hip arthroplasty.

"Given that these rates are based on the results of rigorous studies, they may represent a lower incidence than actual rates observed in clinical practice, in which patients are selected less rigorously and prophylaxis is administered less assiduously," Mr. Januel and his associates noted.

The pooled incidence rates of deep vein thrombosis were lower for both knee patients and hip patients when factor Xa or IIa inhibitors, rather than low-molecular-weight heparin, were given for prophylaxis. "However, we cannot make assertions regarding comparative efficacy among treatments, because our meta-analysis did not directly compare [these agents] as an efficacy meta-analysis would have done," they said.

This study was supported by Alberta Innovates Health Solutions, a government research funding agency, and the International Methodology Consortium for Coded Health Information, a collaboration of health sciences researchers to promote quality of care. Dr. Heit reported ties to Daiichi Sankyo, GTC, Ortho-McNeil-Jansen, the National Heart, Lung, and Blood Institute, the National Human Genome Research Institute, the National Institutes of Health, the Centers for Disease Control and Prevention, and the Mayo Foundation.

For the first time, researchers say they have established benchmarks for the rates of in-hospital venous thromboembolism that occur after total or partial hip arthroplasty and after total or partial knee arthroplasty, according to a report Jan. 18 in JAMA.

In a meta-analysis of 47 studies that documented venous thromboembolism (VTE) event rates in nearly 45,000 patients who received recommended prophylaxis during hospitalization for knee or hip arthroplasty, investigators estimated that approximately 1 in every 100 patients undergoing knee arthroplasty and 1 in every 200 undergoing hip arthroplasty will develop symptomatic VTE before they are discharged.

"These estimates are of value to individual patients and clinicians in the consideration of risks and benefits" of the two procedures. They also are important because rates of in-hospital VTE are increasingly used as indicators of patient safety at individual medical centers, even though the expected background rates haven’t been established until now, said Jean-Marie Januel, a registered nurse with the Institute of Social and Preventive Medicine, Lausanne (Switzerland) University Hospital, and his associates.

"Large numbers of patients worldwide undergo hip and knee replacement procedures annually, and VTE is a widely acknowledged complication. Yet no estimate of symptomatic VTE risk prior to hospital discharge is available from the literature that can be conveyed to patients in the informed consent process," they noted.

Mr. Januel and his colleagues performed a systemic search of the literature to identify studies performed between 1996 and 2011 in which subjects undergoing either hip or knee arthroplasty received VTE prophylaxis according to published guidelines, including either low-molecular-weight heparin or inhibitors of factor Xa or IIa. They found 41 randomized clinical trials and 6 observational studies to include in the meta-analysis.

A total of 22 of the studies were performed in Europe, 14 were in North America, and 11 were in other regions. The mean duration of follow-up after either surgery was 13 days.

This included 21 studies of partial or total hip arthroplasty, 20 of partial or total knee arthroplasty, and 6 studies of both procedures, with a total of 44,844 subjects.

There were 443 cases of symptomatic postoperative VTE that developed before hospital discharge: 288 in the 23,475 knee patients and 155 in the 23,475 hip patients. This included 182 cases of deep vein thrombosis in the knee patients and 93 in the hip patients, as well as 106 cases of pulmonary embolism in the knee patients and 43 in the hip patients.

The pooled incidence rates of VTE were approximately 1% after knee arthroplasty and approximately 0.5% after hip arthroplasty. This means that the background rate of VTE is approximately 1 in 100 knee patients and 1 in 200 hip patients, the investigators said (JAMA 2012;307:294-303).

When the data were broken down by type of VTE, the pooled incidence rates were 0.26% for deep vein thrombosis and 0.14% for pulmonary embolism after knee arthroplasty. The corresponding rates were 0.63% for deep vein thrombosis and 0.27% for pulmonary embolism after hip arthroplasty.

"Given that these rates are based on the results of rigorous studies, they may represent a lower incidence than actual rates observed in clinical practice, in which patients are selected less rigorously and prophylaxis is administered less assiduously," Mr. Januel and his associates noted.

The pooled incidence rates of deep vein thrombosis were lower for both knee patients and hip patients when factor Xa or IIa inhibitors, rather than low-molecular-weight heparin, were given for prophylaxis. "However, we cannot make assertions regarding comparative efficacy among treatments, because our meta-analysis did not directly compare [these agents] as an efficacy meta-analysis would have done," they said.

This study was supported by Alberta Innovates Health Solutions, a government research funding agency, and the International Methodology Consortium for Coded Health Information, a collaboration of health sciences researchers to promote quality of care. Dr. Heit reported ties to Daiichi Sankyo, GTC, Ortho-McNeil-Jansen, the National Heart, Lung, and Blood Institute, the National Human Genome Research Institute, the National Institutes of Health, the Centers for Disease Control and Prevention, and the Mayo Foundation.

SAN DIEGO – Prophylaxis with rivaroxaban achieved significant reductions in venous thromboembolism, compared with two commonly used drugs when put to the test in 5,346 consecutive, unselected patients undergoing major orthopedic surgery.

The incidence of in-hospital symptomatic venous thromboembolism (VTE) was 2.4% with rivaroxaban (Xarelto), compared with 3.9% with low molecular weight heparin (LMWH), and 5.5% with fondaparinux (Arixtra). This corresponds to a relative risk reduction of 39%, compared with LMWH, and 57% compared with fondaparinux.

Rivaroxaban, an oral Factor Xa inhibitor, also has superior safety with regard to major bleeding and surgical complications, according to Dr. Jan Beyer-Westendorf, with the University Clinic at Dresden (Germany) Technical University.

"Patients in real-world major orthopedic surgery benefit from VTE-prophylaxis with rivaroxaban even more than could be expected from the phase III results of the RECORD trial," he said at the annual meeting of the American Society of Hematology.

The four phase III RECORD (REgulation of Coagulation in ORthopedic Surgery to Prevent Deep Vein Thrombosis and Pulmonary Embolism) trials compared rivaroxaban with enoxaparin in more than 12,500 patients undergoing knee and hip replacement. The trials did not evaluate fondaparinux or LMWH, despite being the standard of care at many hospitals.

Rivaroxaban was approved in the United States in July 2011 for DVT prophylaxis in adults undergoing hip and knee replacement surgery, and gained a second indication in November 2011 for stroke prophylaxis in patients with nonvalvular atrial fibrillation.

Dr. Beyer-Westendorf and his colleagues analyzed 5,346 consecutive patients who underwent major orthopedic surgery at the university clinic during three periods: 2005-2007 when LMWH was the standard prophylaxis; 2008-2009 when fondaparinux was the standard; and finally from 2010 to June 2011 when rivaroxaban became the clinic’s standard prophylaxis.

In all, 1,055 patients were treated with rivaroxaban, 1,683 with LMWH, and 2,069 with fondaparinux. Of note, previous VTE was more common at baseline in the rivaroxaban group at 4% vs. 1.4% in the LMWH group, and 1.1% in the fondaparinux group, he said.

Rivaroxaban reduced the relative risk of the composite of proximal DVT, pulmonary embolism, and VTE-related death by 29%, compared with LMWH, and 42% compared with fondaparinux, but the difference between the three groups did not achieve statistical significance (1.0% vs. 1.4% vs. 1.7%), Dr. Beyer-Westendorf said.

In a pooled analysis of RECORD 1, 2, and 3, rivaroxaban significantly reduced the composite of symptomatic VTE and all-cause mortality during the 2-week period after surgery, compared with enoxaparin (0.4% vs. 0.8%), according to the Bayer HealthCare website.

In the current analysis, severe bleeding was significantly lower with rivaroxaban at 7.4% vs. 14.9% with LMWH, and 11.1% with fondaparinux.

Bleeding leading to surgical revisions was also significantly lower at 0.4% vs. 1.7% with LMWH, and 1.1% with fondaparinux.

Dr. Beyer-Westendorf pointed out that severe bleeding rates were less than 1% in the RECORD 1-4 trials using a more narrow definition of severe bleeding as overt bleeding outside of the surgical site. Their analysis used the International Society on Thrombosis and Hemostasis criteria for severe bleeding.

Finally, the reduction in VTE events, bleeding, and surgical revisions was correlated with a significantly shorter median hospital stay in patients given rivaroxaban prophylaxis vs. LMWH or fondaparinux (8.3 days vs. 11.6 days vs. 9.3 days).

Dr. Beyer-Westendorf said it was unlikely that changes in anesthesia or surgical practice over the study period could have attenuated the results. In addition, the researchers conducted a matched-pair analysis to evaluate whether the benefits of rivaroxaban were due to selection or detection bias. Outcomes remained superior for rivaroxaban after matching patients according to age, gender, type of surgery, and history of VTE. Complete compression ultrasound testing also remained constant at about 13% from 2005 to 2010 before falling to 8.2% in 2011 due to fewer complete compression ultrasound–positive findings, Dr. Beyer-Westendorf noted.

"These findings in a large real-world surgery cohort are robust and not significantly influenced by a selection or detection bias," he said.

Dr. Beyer-Westendorf disclosed research grants from and serving as a speaker for Bayer HealthCare, which markets Xarelto.

SAN DIEGO – Prophylaxis with rivaroxaban achieved significant reductions in venous thromboembolism, compared with two commonly used drugs when put to the test in 5,346 consecutive, unselected patients undergoing major orthopedic surgery.

The incidence of in-hospital symptomatic venous thromboembolism (VTE) was 2.4% with rivaroxaban (Xarelto), compared with 3.9% with low molecular weight heparin (LMWH), and 5.5% with fondaparinux (Arixtra). This corresponds to a relative risk reduction of 39%, compared with LMWH, and 57% compared with fondaparinux.

Rivaroxaban, an oral Factor Xa inhibitor, also has superior safety with regard to major bleeding and surgical complications, according to Dr. Jan Beyer-Westendorf, with the University Clinic at Dresden (Germany) Technical University.

"Patients in real-world major orthopedic surgery benefit from VTE-prophylaxis with rivaroxaban even more than could be expected from the phase III results of the RECORD trial," he said at the annual meeting of the American Society of Hematology.

The four phase III RECORD (REgulation of Coagulation in ORthopedic Surgery to Prevent Deep Vein Thrombosis and Pulmonary Embolism) trials compared rivaroxaban with enoxaparin in more than 12,500 patients undergoing knee and hip replacement. The trials did not evaluate fondaparinux or LMWH, despite being the standard of care at many hospitals.

Rivaroxaban was approved in the United States in July 2011 for DVT prophylaxis in adults undergoing hip and knee replacement surgery, and gained a second indication in November 2011 for stroke prophylaxis in patients with nonvalvular atrial fibrillation.

Dr. Beyer-Westendorf and his colleagues analyzed 5,346 consecutive patients who underwent major orthopedic surgery at the university clinic during three periods: 2005-2007 when LMWH was the standard prophylaxis; 2008-2009 when fondaparinux was the standard; and finally from 2010 to June 2011 when rivaroxaban became the clinic’s standard prophylaxis.

In all, 1,055 patients were treated with rivaroxaban, 1,683 with LMWH, and 2,069 with fondaparinux. Of note, previous VTE was more common at baseline in the rivaroxaban group at 4% vs. 1.4% in the LMWH group, and 1.1% in the fondaparinux group, he said.

Rivaroxaban reduced the relative risk of the composite of proximal DVT, pulmonary embolism, and VTE-related death by 29%, compared with LMWH, and 42% compared with fondaparinux, but the difference between the three groups did not achieve statistical significance (1.0% vs. 1.4% vs. 1.7%), Dr. Beyer-Westendorf said.

In a pooled analysis of RECORD 1, 2, and 3, rivaroxaban significantly reduced the composite of symptomatic VTE and all-cause mortality during the 2-week period after surgery, compared with enoxaparin (0.4% vs. 0.8%), according to the Bayer HealthCare website.

In the current analysis, severe bleeding was significantly lower with rivaroxaban at 7.4% vs. 14.9% with LMWH, and 11.1% with fondaparinux.

Bleeding leading to surgical revisions was also significantly lower at 0.4% vs. 1.7% with LMWH, and 1.1% with fondaparinux.

Dr. Beyer-Westendorf pointed out that severe bleeding rates were less than 1% in the RECORD 1-4 trials using a more narrow definition of severe bleeding as overt bleeding outside of the surgical site. Their analysis used the International Society on Thrombosis and Hemostasis criteria for severe bleeding.

Finally, the reduction in VTE events, bleeding, and surgical revisions was correlated with a significantly shorter median hospital stay in patients given rivaroxaban prophylaxis vs. LMWH or fondaparinux (8.3 days vs. 11.6 days vs. 9.3 days).

Dr. Beyer-Westendorf said it was unlikely that changes in anesthesia or surgical practice over the study period could have attenuated the results. In addition, the researchers conducted a matched-pair analysis to evaluate whether the benefits of rivaroxaban were due to selection or detection bias. Outcomes remained superior for rivaroxaban after matching patients according to age, gender, type of surgery, and history of VTE. Complete compression ultrasound testing also remained constant at about 13% from 2005 to 2010 before falling to 8.2% in 2011 due to fewer complete compression ultrasound–positive findings, Dr. Beyer-Westendorf noted.

"These findings in a large real-world surgery cohort are robust and not significantly influenced by a selection or detection bias," he said.

Dr. Beyer-Westendorf disclosed research grants from and serving as a speaker for Bayer HealthCare, which markets Xarelto.

SAN DIEGO – Prophylaxis with rivaroxaban achieved significant reductions in venous thromboembolism, compared with two commonly used drugs when put to the test in 5,346 consecutive, unselected patients undergoing major orthopedic surgery.

The incidence of in-hospital symptomatic venous thromboembolism (VTE) was 2.4% with rivaroxaban (Xarelto), compared with 3.9% with low molecular weight heparin (LMWH), and 5.5% with fondaparinux (Arixtra). This corresponds to a relative risk reduction of 39%, compared with LMWH, and 57% compared with fondaparinux.

Rivaroxaban, an oral Factor Xa inhibitor, also has superior safety with regard to major bleeding and surgical complications, according to Dr. Jan Beyer-Westendorf, with the University Clinic at Dresden (Germany) Technical University.

"Patients in real-world major orthopedic surgery benefit from VTE-prophylaxis with rivaroxaban even more than could be expected from the phase III results of the RECORD trial," he said at the annual meeting of the American Society of Hematology.

The four phase III RECORD (REgulation of Coagulation in ORthopedic Surgery to Prevent Deep Vein Thrombosis and Pulmonary Embolism) trials compared rivaroxaban with enoxaparin in more than 12,500 patients undergoing knee and hip replacement. The trials did not evaluate fondaparinux or LMWH, despite being the standard of care at many hospitals.

Rivaroxaban was approved in the United States in July 2011 for DVT prophylaxis in adults undergoing hip and knee replacement surgery, and gained a second indication in November 2011 for stroke prophylaxis in patients with nonvalvular atrial fibrillation.

Dr. Beyer-Westendorf and his colleagues analyzed 5,346 consecutive patients who underwent major orthopedic surgery at the university clinic during three periods: 2005-2007 when LMWH was the standard prophylaxis; 2008-2009 when fondaparinux was the standard; and finally from 2010 to June 2011 when rivaroxaban became the clinic’s standard prophylaxis.

In all, 1,055 patients were treated with rivaroxaban, 1,683 with LMWH, and 2,069 with fondaparinux. Of note, previous VTE was more common at baseline in the rivaroxaban group at 4% vs. 1.4% in the LMWH group, and 1.1% in the fondaparinux group, he said.

Rivaroxaban reduced the relative risk of the composite of proximal DVT, pulmonary embolism, and VTE-related death by 29%, compared with LMWH, and 42% compared with fondaparinux, but the difference between the three groups did not achieve statistical significance (1.0% vs. 1.4% vs. 1.7%), Dr. Beyer-Westendorf said.

In a pooled analysis of RECORD 1, 2, and 3, rivaroxaban significantly reduced the composite of symptomatic VTE and all-cause mortality during the 2-week period after surgery, compared with enoxaparin (0.4% vs. 0.8%), according to the Bayer HealthCare website.

In the current analysis, severe bleeding was significantly lower with rivaroxaban at 7.4% vs. 14.9% with LMWH, and 11.1% with fondaparinux.

Bleeding leading to surgical revisions was also significantly lower at 0.4% vs. 1.7% with LMWH, and 1.1% with fondaparinux.

Dr. Beyer-Westendorf pointed out that severe bleeding rates were less than 1% in the RECORD 1-4 trials using a more narrow definition of severe bleeding as overt bleeding outside of the surgical site. Their analysis used the International Society on Thrombosis and Hemostasis criteria for severe bleeding.

Finally, the reduction in VTE events, bleeding, and surgical revisions was correlated with a significantly shorter median hospital stay in patients given rivaroxaban prophylaxis vs. LMWH or fondaparinux (8.3 days vs. 11.6 days vs. 9.3 days).

Dr. Beyer-Westendorf said it was unlikely that changes in anesthesia or surgical practice over the study period could have attenuated the results. In addition, the researchers conducted a matched-pair analysis to evaluate whether the benefits of rivaroxaban were due to selection or detection bias. Outcomes remained superior for rivaroxaban after matching patients according to age, gender, type of surgery, and history of VTE. Complete compression ultrasound testing also remained constant at about 13% from 2005 to 2010 before falling to 8.2% in 2011 due to fewer complete compression ultrasound–positive findings, Dr. Beyer-Westendorf noted.

"These findings in a large real-world surgery cohort are robust and not significantly influenced by a selection or detection bias," he said.

Dr. Beyer-Westendorf disclosed research grants from and serving as a speaker for Bayer HealthCare, which markets Xarelto.

BOSTON – Just 1% of all surgical procedures are associated with complex surgical site infections, but many develop in association with ill-suited prophylactic antibiotic regimens, according to an analysis of more than 2.4 million American who underwent cardiac or orthopedic surgery during 2006-2009.

Nevertheless, "the vast majority [of surgery patients] don’t get SSIs. Do we want to modify treatment for all patients to address the small proportion who get complex SSIs?" asked Dr. Dale W. Bratzler.

The low overall rate of complex SSIs suggests that any changes to standard SSI prophylaxis regimens should proceed cautiously. "What we need most are strategies for identifying patients at high risk for SSI due to drug-resistant organisms for targeting modified antimicrobial prophylaxis regimens," said Dr. Bratzler, a professor in the department of health administration and policy of the University of Oklahoma, Oklahoma City.

The analysis he reported at the annual meeting of the Infectious Diseases Society of America used data from two large U.S. databases collected from January 2006 to December 2009. Information on the pathogen distribution of SSIs came from the National Healthcare Safety Network database of the Centers for Disease Control and Prevention, which included data from 1,389 U.S. hospitals during this period on the number and type of SSIs that occurred in patients who underwent coronary artery bypass grafting (CABG), and those who had primary total hip or total knee replacement surgery. The second database, from the Hospital Inpatient Quality Reporting Program of the Centers for Medicare and Medicaid Services, collected data on the type of antimicrobial prophylaxis received by patients who underwent these surgical procedures at 3,330 U.S. hospitals.

"Do we want to modify treatment for all patients to address the small proportion who get complex SSIs?"

The National Healthcare Safety Network data showed that a total of 3,024 patients developed a complex SSI among the 207,053 who underwent CABG (1.5%), and 3,532 patients had a complex SSI among the 495,529 patients who had primary hip or knee replacement surgery (0.7%), Dr. Bratzler reported. Complex SSIs were defined as either deep incisional infections, or infections of an organ or surgical space. Among the CABG-associated complex SSIs, 34% were caused by gram-negative bacteria, with the balance caused by gram-positive pathogens, and 17% of all SSIs involved methicillin-resistant Staphylococcus aureus (MRSA). In the arthroplasty patients, 18% of the complex SSIs involved a gram-negative pathogen, and 21% of all infections had MRSA involvement.

The data on type of antibiotic prophylaxis used showed that among 428,541 patients who underwent CABG in this dataset, 67% received "standard" prophylaxis with either cefazolin or cefuroxime; 12% received a regimen designed for patients with beta-lactam allergy with either vancomycin or clindamycin, plus an aminoglycoside added at the provider’s discretion; and 15% had prophylaxis with an extended-spectrum regimen consisting of either vancomycin plus cefazolin or cefuroxime, or an aminoglycoside plus cefazolin or cefuroxime. The remaining 6% of patients received another prophylaxis regimen.

The prophylaxis data for 2,007,162 arthroplasty patients showed that the standard regimen was used in 77%, the beta-lactam allergy regimen in 13%, and the extended-spectrum regimen in 7%, with the remaining 3% of patients receiving something else.

Dr. Bratzler then compared the expected efficacy of the three most commonly used regimens against the pattern of SSIs that actually occurred in these patients. Patients who received the standard regimen could expect protection against about 40% of the types of bacteria that actually wound up producing SSIs. Patients who received the beta-lactam allergy regimens could expect protection against 56%-96% of the pathogens that actually caused the SSIs, and patients who received the extended-spectrum regimens could expect protection against 69%-96%, he said.

The researchers could not do a more detailed analysis of the relationship between the type of prophylaxis used and the pattern of SSIs that subsequently developed because both databases were anonymous, which precluded cross-referencing the information.

Dr. Bratzler said that he had no disclosures.

BOSTON – Just 1% of all surgical procedures are associated with complex surgical site infections, but many develop in association with ill-suited prophylactic antibiotic regimens, according to an analysis of more than 2.4 million American who underwent cardiac or orthopedic surgery during 2006-2009.

Nevertheless, "the vast majority [of surgery patients] don’t get SSIs. Do we want to modify treatment for all patients to address the small proportion who get complex SSIs?" asked Dr. Dale W. Bratzler.

The low overall rate of complex SSIs suggests that any changes to standard SSI prophylaxis regimens should proceed cautiously. "What we need most are strategies for identifying patients at high risk for SSI due to drug-resistant organisms for targeting modified antimicrobial prophylaxis regimens," said Dr. Bratzler, a professor in the department of health administration and policy of the University of Oklahoma, Oklahoma City.

The analysis he reported at the annual meeting of the Infectious Diseases Society of America used data from two large U.S. databases collected from January 2006 to December 2009. Information on the pathogen distribution of SSIs came from the National Healthcare Safety Network database of the Centers for Disease Control and Prevention, which included data from 1,389 U.S. hospitals during this period on the number and type of SSIs that occurred in patients who underwent coronary artery bypass grafting (CABG), and those who had primary total hip or total knee replacement surgery. The second database, from the Hospital Inpatient Quality Reporting Program of the Centers for Medicare and Medicaid Services, collected data on the type of antimicrobial prophylaxis received by patients who underwent these surgical procedures at 3,330 U.S. hospitals.

"Do we want to modify treatment for all patients to address the small proportion who get complex SSIs?"

The National Healthcare Safety Network data showed that a total of 3,024 patients developed a complex SSI among the 207,053 who underwent CABG (1.5%), and 3,532 patients had a complex SSI among the 495,529 patients who had primary hip or knee replacement surgery (0.7%), Dr. Bratzler reported. Complex SSIs were defined as either deep incisional infections, or infections of an organ or surgical space. Among the CABG-associated complex SSIs, 34% were caused by gram-negative bacteria, with the balance caused by gram-positive pathogens, and 17% of all SSIs involved methicillin-resistant Staphylococcus aureus (MRSA). In the arthroplasty patients, 18% of the complex SSIs involved a gram-negative pathogen, and 21% of all infections had MRSA involvement.

The data on type of antibiotic prophylaxis used showed that among 428,541 patients who underwent CABG in this dataset, 67% received "standard" prophylaxis with either cefazolin or cefuroxime; 12% received a regimen designed for patients with beta-lactam allergy with either vancomycin or clindamycin, plus an aminoglycoside added at the provider’s discretion; and 15% had prophylaxis with an extended-spectrum regimen consisting of either vancomycin plus cefazolin or cefuroxime, or an aminoglycoside plus cefazolin or cefuroxime. The remaining 6% of patients received another prophylaxis regimen.

The prophylaxis data for 2,007,162 arthroplasty patients showed that the standard regimen was used in 77%, the beta-lactam allergy regimen in 13%, and the extended-spectrum regimen in 7%, with the remaining 3% of patients receiving something else.

Dr. Bratzler then compared the expected efficacy of the three most commonly used regimens against the pattern of SSIs that actually occurred in these patients. Patients who received the standard regimen could expect protection against about 40% of the types of bacteria that actually wound up producing SSIs. Patients who received the beta-lactam allergy regimens could expect protection against 56%-96% of the pathogens that actually caused the SSIs, and patients who received the extended-spectrum regimens could expect protection against 69%-96%, he said.

The researchers could not do a more detailed analysis of the relationship between the type of prophylaxis used and the pattern of SSIs that subsequently developed because both databases were anonymous, which precluded cross-referencing the information.

Dr. Bratzler said that he had no disclosures.

BOSTON – Just 1% of all surgical procedures are associated with complex surgical site infections, but many develop in association with ill-suited prophylactic antibiotic regimens, according to an analysis of more than 2.4 million American who underwent cardiac or orthopedic surgery during 2006-2009.

Nevertheless, "the vast majority [of surgery patients] don’t get SSIs. Do we want to modify treatment for all patients to address the small proportion who get complex SSIs?" asked Dr. Dale W. Bratzler.

The low overall rate of complex SSIs suggests that any changes to standard SSI prophylaxis regimens should proceed cautiously. "What we need most are strategies for identifying patients at high risk for SSI due to drug-resistant organisms for targeting modified antimicrobial prophylaxis regimens," said Dr. Bratzler, a professor in the department of health administration and policy of the University of Oklahoma, Oklahoma City.

The analysis he reported at the annual meeting of the Infectious Diseases Society of America used data from two large U.S. databases collected from January 2006 to December 2009. Information on the pathogen distribution of SSIs came from the National Healthcare Safety Network database of the Centers for Disease Control and Prevention, which included data from 1,389 U.S. hospitals during this period on the number and type of SSIs that occurred in patients who underwent coronary artery bypass grafting (CABG), and those who had primary total hip or total knee replacement surgery. The second database, from the Hospital Inpatient Quality Reporting Program of the Centers for Medicare and Medicaid Services, collected data on the type of antimicrobial prophylaxis received by patients who underwent these surgical procedures at 3,330 U.S. hospitals.

"Do we want to modify treatment for all patients to address the small proportion who get complex SSIs?"

The National Healthcare Safety Network data showed that a total of 3,024 patients developed a complex SSI among the 207,053 who underwent CABG (1.5%), and 3,532 patients had a complex SSI among the 495,529 patients who had primary hip or knee replacement surgery (0.7%), Dr. Bratzler reported. Complex SSIs were defined as either deep incisional infections, or infections of an organ or surgical space. Among the CABG-associated complex SSIs, 34% were caused by gram-negative bacteria, with the balance caused by gram-positive pathogens, and 17% of all SSIs involved methicillin-resistant Staphylococcus aureus (MRSA). In the arthroplasty patients, 18% of the complex SSIs involved a gram-negative pathogen, and 21% of all infections had MRSA involvement.

The data on type of antibiotic prophylaxis used showed that among 428,541 patients who underwent CABG in this dataset, 67% received "standard" prophylaxis with either cefazolin or cefuroxime; 12% received a regimen designed for patients with beta-lactam allergy with either vancomycin or clindamycin, plus an aminoglycoside added at the provider’s discretion; and 15% had prophylaxis with an extended-spectrum regimen consisting of either vancomycin plus cefazolin or cefuroxime, or an aminoglycoside plus cefazolin or cefuroxime. The remaining 6% of patients received another prophylaxis regimen.

The prophylaxis data for 2,007,162 arthroplasty patients showed that the standard regimen was used in 77%, the beta-lactam allergy regimen in 13%, and the extended-spectrum regimen in 7%, with the remaining 3% of patients receiving something else.

Dr. Bratzler then compared the expected efficacy of the three most commonly used regimens against the pattern of SSIs that actually occurred in these patients. Patients who received the standard regimen could expect protection against about 40% of the types of bacteria that actually wound up producing SSIs. Patients who received the beta-lactam allergy regimens could expect protection against 56%-96% of the pathogens that actually caused the SSIs, and patients who received the extended-spectrum regimens could expect protection against 69%-96%, he said.

The researchers could not do a more detailed analysis of the relationship between the type of prophylaxis used and the pattern of SSIs that subsequently developed because both databases were anonymous, which precluded cross-referencing the information.

Dr. Bratzler said that he had no disclosures.

SAN DIEGO – The more severe an anterior cruciate ligament injury, the more likely patients are to develop arthritis in the injured knee; structural changes might even be seen within 4 years of the trauma, a small study has shown.

In results presented at the World Congress on Osteoarthritis, patients who had had anterior cruciate ligament (ACL) reconstruction were four times more likely to have abnormal joint space narrowing by then if they also had a defect that extended more than halfway through their femoral cartilage (International Cartilage Repair Society grade III injury), a menisectomy, or both (odds ratio 4.11; 95% confidence interval 1.01-39.55, P = .05).

"These people were highly functioning; they were all athletic people. They had no symptoms of osteoarthritis," said lead investigator Timothy Tourville of the University of Vermont Center for Clinical and Translational Science in Burlington.

"Historically, most studies haven’t been able to demonstrate differences in [less than] 10 or 15 years. I think being able to pick them up at 4 years and identifying those who are at high risk for structural change is very important," rheumatologist David Hunter said in an interview.

"If, at the time of the injury, there is more substantive damage to either [the patient’s] cartilage or their meniscus, you are going to be more cautious about encouraging them to return to high physical activity and potentially redamaging their" knee, said Dr. Hunter, professor of medicine at the University of Sydney (Australia).

The 38 ACL patients in the study, about half women, were under 51 years of age and not obese. Their ACLs were reconstructed within a half-year of their injury, and none had gotten intra-articular injections. Other than their injury, they were in good health with no other joint problems. Baseline radiographs were compared with films at 3-4 years.

More than 60% (8/13) of those with grade III cartilage injuries had abnormal joint space narrowing at that point, compared with 28% (7/25) of those with no more than grade II injuries – defects extending less than halfway through their femoral cartilage – and intact menisci in both compartments.

"Abnormal" meant that the joint space difference between patients’ injured and uninjured knees fell outside the 95% confidence interval of bilateral differences measured in 32 matched controls.

The conference was sponsored by the Osteoarthritis Research Society International. Mr. Tourville and Dr. Hunter said they had no relevant financial disclosures. The National Institute of Arthritis and Musculoskeletal and Skin Diseases supported the work.

SAN DIEGO – The more severe an anterior cruciate ligament injury, the more likely patients are to develop arthritis in the injured knee; structural changes might even be seen within 4 years of the trauma, a small study has shown.

In results presented at the World Congress on Osteoarthritis, patients who had had anterior cruciate ligament (ACL) reconstruction were four times more likely to have abnormal joint space narrowing by then if they also had a defect that extended more than halfway through their femoral cartilage (International Cartilage Repair Society grade III injury), a menisectomy, or both (odds ratio 4.11; 95% confidence interval 1.01-39.55, P = .05).

"These people were highly functioning; they were all athletic people. They had no symptoms of osteoarthritis," said lead investigator Timothy Tourville of the University of Vermont Center for Clinical and Translational Science in Burlington.

"Historically, most studies haven’t been able to demonstrate differences in [less than] 10 or 15 years. I think being able to pick them up at 4 years and identifying those who are at high risk for structural change is very important," rheumatologist David Hunter said in an interview.

"If, at the time of the injury, there is more substantive damage to either [the patient’s] cartilage or their meniscus, you are going to be more cautious about encouraging them to return to high physical activity and potentially redamaging their" knee, said Dr. Hunter, professor of medicine at the University of Sydney (Australia).

The 38 ACL patients in the study, about half women, were under 51 years of age and not obese. Their ACLs were reconstructed within a half-year of their injury, and none had gotten intra-articular injections. Other than their injury, they were in good health with no other joint problems. Baseline radiographs were compared with films at 3-4 years.

More than 60% (8/13) of those with grade III cartilage injuries had abnormal joint space narrowing at that point, compared with 28% (7/25) of those with no more than grade II injuries – defects extending less than halfway through their femoral cartilage – and intact menisci in both compartments.

"Abnormal" meant that the joint space difference between patients’ injured and uninjured knees fell outside the 95% confidence interval of bilateral differences measured in 32 matched controls.

The conference was sponsored by the Osteoarthritis Research Society International. Mr. Tourville and Dr. Hunter said they had no relevant financial disclosures. The National Institute of Arthritis and Musculoskeletal and Skin Diseases supported the work.

SAN DIEGO – The more severe an anterior cruciate ligament injury, the more likely patients are to develop arthritis in the injured knee; structural changes might even be seen within 4 years of the trauma, a small study has shown.

In results presented at the World Congress on Osteoarthritis, patients who had had anterior cruciate ligament (ACL) reconstruction were four times more likely to have abnormal joint space narrowing by then if they also had a defect that extended more than halfway through their femoral cartilage (International Cartilage Repair Society grade III injury), a menisectomy, or both (odds ratio 4.11; 95% confidence interval 1.01-39.55, P = .05).

"These people were highly functioning; they were all athletic people. They had no symptoms of osteoarthritis," said lead investigator Timothy Tourville of the University of Vermont Center for Clinical and Translational Science in Burlington.

"Historically, most studies haven’t been able to demonstrate differences in [less than] 10 or 15 years. I think being able to pick them up at 4 years and identifying those who are at high risk for structural change is very important," rheumatologist David Hunter said in an interview.

"If, at the time of the injury, there is more substantive damage to either [the patient’s] cartilage or their meniscus, you are going to be more cautious about encouraging them to return to high physical activity and potentially redamaging their" knee, said Dr. Hunter, professor of medicine at the University of Sydney (Australia).

The 38 ACL patients in the study, about half women, were under 51 years of age and not obese. Their ACLs were reconstructed within a half-year of their injury, and none had gotten intra-articular injections. Other than their injury, they were in good health with no other joint problems. Baseline radiographs were compared with films at 3-4 years.

More than 60% (8/13) of those with grade III cartilage injuries had abnormal joint space narrowing at that point, compared with 28% (7/25) of those with no more than grade II injuries – defects extending less than halfway through their femoral cartilage – and intact menisci in both compartments.

"Abnormal" meant that the joint space difference between patients’ injured and uninjured knees fell outside the 95% confidence interval of bilateral differences measured in 32 matched controls.

The conference was sponsored by the Osteoarthritis Research Society International. Mr. Tourville and Dr. Hunter said they had no relevant financial disclosures. The National Institute of Arthritis and Musculoskeletal and Skin Diseases supported the work.

SAN DIEGO – Structural damage due to osteoarthritis appears to be more common, and more severe, in the patellofemoral joint than in the tibiofemoral joint, making the patellofemoral joint the predominant one affected by knee osteoarthritis, according to findings from a magnetic resonance imaging–based study involving nearly 1,000 people.

It’s important that future research "not only address the tibiofemoral joint, but also the patellofemoral joint," said lead investigator Joshua Stefanik, Ph.D., a research associate in Boston University’s Clinical Epidemiology, Research, and Training Unit, said at the World Congress on Osteoarthritis.

The findings are surprising because "historically, everybody focuses on the tibiofemoral joint. We are probably missing a lot of disease" by relying on radiographs and clinical exams for diagnosis; they aren’t very good at picking up problems in the patellofemoral joint (PFJ), said Dr. David Hunter in an interview.

But even if it does a better job, "I wouldn’t encourage people to do an MRI if they have knee osteoarthritis." The results won’t change clinical management, and if meniscal tears are found, patients may end up in the operating room having an unnecessary meniscectomy, "which doesn’t do them any favors. Typically, the meniscus isn’t the problem." Tears are common and generally asymptomatic, said Dr. Hunter, a professor of medicine at the University of Sydney.

"Once clinicians are better educated about [such] dangers, MRI may be a good way to pick up [PFJ] disease," he said. Patellofemoral braces and PFJ-modifying shoe inserts are among the management options.

The 970 subjects in the study were part of the Framingham (Mass.) Osteoarthritis Study and were recruited from that community without regards to knee pain or osteoarthritis. Their mean age was 63.4 years and mean body mass index was 28.6 kg/m²; 57% were women, and 22% complained of knee pain. Cases of inflammatory arthritis were excluded. One knee was studied in each patient.

Radiographs found tibiofemoral joint (TFJ) damage in 11.9% of subjects, PFJ damage in just 1.4%, and damage in both joints in 5.9%.

The prevalence of PFJ problems was much higher on MRI; 20.4% had PFJ cartilage damage (WORMS [Whole-Organ Magnetic Resonance Imaging Score] greater than or equal to 2); 10.4% TFJ damage; and 44.2% damage in both joints. When both joints were involved, the most severe lesions were usually in the PFJ.

Similarly, 18.6% of subjects had PFJ cartilage damage extending down to bone (WORMS 2.5, greater than or equal to 5); 8% had TFJ damage down to bone; and 7.8% damage down to the bone in both joints.

The team found PFJ bone marrow lesions (WORMS greater than or equal to 1) in 17.9% of subjects; TFJ lesions in 16.5%; and lesions in both joints in 21.8%. Again, the most severe lesions were usually in the PFJ.

Finally, 15.2% of the Framingham subjects had both bone marrow lesions and cartilage damage down to bone in their PFJs, while only 8.8% had both problems in their TFJs; 4.4% had them in both joints.

Patterns were similar for men and women, and in knees with pain. The researchers used 1.5 T MRI with turbo spin-echo, fat-suppressed images in the sagittal, coronal, and axial planes.

The congress was sponsored by the Osteoarthritis Research Society International. Dr. Stefanik and Dr. Hunter reported no financial disclosures. The National Institutes of Health and the Arthritis Foundation funded the work.

SAN DIEGO – Structural damage due to osteoarthritis appears to be more common, and more severe, in the patellofemoral joint than in the tibiofemoral joint, making the patellofemoral joint the predominant one affected by knee osteoarthritis, according to findings from a magnetic resonance imaging–based study involving nearly 1,000 people.

It’s important that future research "not only address the tibiofemoral joint, but also the patellofemoral joint," said lead investigator Joshua Stefanik, Ph.D., a research associate in Boston University’s Clinical Epidemiology, Research, and Training Unit, said at the World Congress on Osteoarthritis.

The findings are surprising because "historically, everybody focuses on the tibiofemoral joint. We are probably missing a lot of disease" by relying on radiographs and clinical exams for diagnosis; they aren’t very good at picking up problems in the patellofemoral joint (PFJ), said Dr. David Hunter in an interview.

But even if it does a better job, "I wouldn’t encourage people to do an MRI if they have knee osteoarthritis." The results won’t change clinical management, and if meniscal tears are found, patients may end up in the operating room having an unnecessary meniscectomy, "which doesn’t do them any favors. Typically, the meniscus isn’t the problem." Tears are common and generally asymptomatic, said Dr. Hunter, a professor of medicine at the University of Sydney.

"Once clinicians are better educated about [such] dangers, MRI may be a good way to pick up [PFJ] disease," he said. Patellofemoral braces and PFJ-modifying shoe inserts are among the management options.

The 970 subjects in the study were part of the Framingham (Mass.) Osteoarthritis Study and were recruited from that community without regards to knee pain or osteoarthritis. Their mean age was 63.4 years and mean body mass index was 28.6 kg/m²; 57% were women, and 22% complained of knee pain. Cases of inflammatory arthritis were excluded. One knee was studied in each patient.

Radiographs found tibiofemoral joint (TFJ) damage in 11.9% of subjects, PFJ damage in just 1.4%, and damage in both joints in 5.9%.

The prevalence of PFJ problems was much higher on MRI; 20.4% had PFJ cartilage damage (WORMS [Whole-Organ Magnetic Resonance Imaging Score] greater than or equal to 2); 10.4% TFJ damage; and 44.2% damage in both joints. When both joints were involved, the most severe lesions were usually in the PFJ.

Similarly, 18.6% of subjects had PFJ cartilage damage extending down to bone (WORMS 2.5, greater than or equal to 5); 8% had TFJ damage down to bone; and 7.8% damage down to the bone in both joints.

The team found PFJ bone marrow lesions (WORMS greater than or equal to 1) in 17.9% of subjects; TFJ lesions in 16.5%; and lesions in both joints in 21.8%. Again, the most severe lesions were usually in the PFJ.

Finally, 15.2% of the Framingham subjects had both bone marrow lesions and cartilage damage down to bone in their PFJs, while only 8.8% had both problems in their TFJs; 4.4% had them in both joints.

Patterns were similar for men and women, and in knees with pain. The researchers used 1.5 T MRI with turbo spin-echo, fat-suppressed images in the sagittal, coronal, and axial planes.

The congress was sponsored by the Osteoarthritis Research Society International. Dr. Stefanik and Dr. Hunter reported no financial disclosures. The National Institutes of Health and the Arthritis Foundation funded the work.

SAN DIEGO – Structural damage due to osteoarthritis appears to be more common, and more severe, in the patellofemoral joint than in the tibiofemoral joint, making the patellofemoral joint the predominant one affected by knee osteoarthritis, according to findings from a magnetic resonance imaging–based study involving nearly 1,000 people.

It’s important that future research "not only address the tibiofemoral joint, but also the patellofemoral joint," said lead investigator Joshua Stefanik, Ph.D., a research associate in Boston University’s Clinical Epidemiology, Research, and Training Unit, said at the World Congress on Osteoarthritis.

The findings are surprising because "historically, everybody focuses on the tibiofemoral joint. We are probably missing a lot of disease" by relying on radiographs and clinical exams for diagnosis; they aren’t very good at picking up problems in the patellofemoral joint (PFJ), said Dr. David Hunter in an interview.

But even if it does a better job, "I wouldn’t encourage people to do an MRI if they have knee osteoarthritis." The results won’t change clinical management, and if meniscal tears are found, patients may end up in the operating room having an unnecessary meniscectomy, "which doesn’t do them any favors. Typically, the meniscus isn’t the problem." Tears are common and generally asymptomatic, said Dr. Hunter, a professor of medicine at the University of Sydney.

"Once clinicians are better educated about [such] dangers, MRI may be a good way to pick up [PFJ] disease," he said. Patellofemoral braces and PFJ-modifying shoe inserts are among the management options.

The 970 subjects in the study were part of the Framingham (Mass.) Osteoarthritis Study and were recruited from that community without regards to knee pain or osteoarthritis. Their mean age was 63.4 years and mean body mass index was 28.6 kg/m²; 57% were women, and 22% complained of knee pain. Cases of inflammatory arthritis were excluded. One knee was studied in each patient.

Radiographs found tibiofemoral joint (TFJ) damage in 11.9% of subjects, PFJ damage in just 1.4%, and damage in both joints in 5.9%.

The prevalence of PFJ problems was much higher on MRI; 20.4% had PFJ cartilage damage (WORMS [Whole-Organ Magnetic Resonance Imaging Score] greater than or equal to 2); 10.4% TFJ damage; and 44.2% damage in both joints. When both joints were involved, the most severe lesions were usually in the PFJ.

Similarly, 18.6% of subjects had PFJ cartilage damage extending down to bone (WORMS 2.5, greater than or equal to 5); 8% had TFJ damage down to bone; and 7.8% damage down to the bone in both joints.

The team found PFJ bone marrow lesions (WORMS greater than or equal to 1) in 17.9% of subjects; TFJ lesions in 16.5%; and lesions in both joints in 21.8%. Again, the most severe lesions were usually in the PFJ.

Finally, 15.2% of the Framingham subjects had both bone marrow lesions and cartilage damage down to bone in their PFJs, while only 8.8% had both problems in their TFJs; 4.4% had them in both joints.

Patterns were similar for men and women, and in knees with pain. The researchers used 1.5 T MRI with turbo spin-echo, fat-suppressed images in the sagittal, coronal, and axial planes.

The congress was sponsored by the Osteoarthritis Research Society International. Dr. Stefanik and Dr. Hunter reported no financial disclosures. The National Institutes of Health and the Arthritis Foundation funded the work.

SAN DIEGO – It’s not unusual for total knee replacement patients to have arthritis in other joints, and it negatively impacts surgery outcomes, Toronto researchers have found.

In their study, 420 of 494 knee replacement patients (85%) reported problems in at least one other joint. Those with foot or ankle arthritis had a significantly reduced chance of achieving an MCID (Minimally Clinically Important Difference) on postoperative WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) pain and function scores (odds ratio pain 0.32, 95% confidence interval 0.185-0.544; OR function 0.53, 95% CI 0.303, 0.940).

Patients who reported neck problems also had reduced odds of achieving an MCID on physical function WOMAC scores (OR 0.37, 95% CI 0.183, 0.726).

"It’s not surprising that ankles and feet [were] significant. [They] impact activities for which lower-extremity joints are involved. How the upper extremities are associated here, in particular the neck, is unclear," said lead investigator Anthony Perruccio, Ph.D., an epidemiologist and research scientist at the Toronto Western Research Institute.

Because patients with neck problems also saw less improvement in fatigue, anxiety, depression, and pain, there may also be a mental health component, he said.

Whatever the case, the lesson is to treat the whole patient, not just the knee. Referrals to other types of providers are appropriate, including physiotherapists and mental health counselors as needed, said Dr. Perruccio.

"There’s more than just the one joint that’s involved here. Outcomes could be improved if a more holistic approach to osteoarthritis management were considered," he said.

All 494 patients had primary, unilateral knee replacements secondary to osteoarthritis. Their mean age was 65, 65% were women, and almost half were obese.

The patients filled out several surveys before their operations, including WOMAC and other pain and function scales plus the Profile of Mood States (POMS) fatigue scale, the Knee injury and Osteoarthritis Outcome Score (KOOS) sports and recreation scale, and the Hospital Anxiety and Depression Scale (HADS). They also pointed out on a homunculus diagram which joints were causing trouble.

Almost half (46%) reported pain on most days in four or more joints in addition to their operative knee. The nonoperative knee was a problem for 57%, elbows/wrists/hands were problematic for 49%, ankles/feet for 36%, the back for 31%, shoulders for 29%, hips for 25%, and neck for 22%. Just 15% said only their operative knee was symptomatic.

A year after their operation, patients took the surveys again. Those with back problems tended to see less improvement in fatigue at 1 year. Those with ankle or foot arthritis – in addition to diminished returns on pain and function – also saw less improvement than others in depression and sports and recreation scores.

The congress was sponsored by the Osteoarthritis Research Society International. Dr. Perruccio said he had no relevant financial disclosures. The work was funded by the Canadian Institutes of Health Research.

* Correction, 10/21/11: The original headline of this story, "Knee Replacement Worsens Arthritis in Other Joints," misrepresented the findings of this study. The headline has been revised.

SAN DIEGO – It’s not unusual for total knee replacement patients to have arthritis in other joints, and it negatively impacts surgery outcomes, Toronto researchers have found.

In their study, 420 of 494 knee replacement patients (85%) reported problems in at least one other joint. Those with foot or ankle arthritis had a significantly reduced chance of achieving an MCID (Minimally Clinically Important Difference) on postoperative WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) pain and function scores (odds ratio pain 0.32, 95% confidence interval 0.185-0.544; OR function 0.53, 95% CI 0.303, 0.940).

Patients who reported neck problems also had reduced odds of achieving an MCID on physical function WOMAC scores (OR 0.37, 95% CI 0.183, 0.726).

"It’s not surprising that ankles and feet [were] significant. [They] impact activities for which lower-extremity joints are involved. How the upper extremities are associated here, in particular the neck, is unclear," said lead investigator Anthony Perruccio, Ph.D., an epidemiologist and research scientist at the Toronto Western Research Institute.

Because patients with neck problems also saw less improvement in fatigue, anxiety, depression, and pain, there may also be a mental health component, he said.

Whatever the case, the lesson is to treat the whole patient, not just the knee. Referrals to other types of providers are appropriate, including physiotherapists and mental health counselors as needed, said Dr. Perruccio.

"There’s more than just the one joint that’s involved here. Outcomes could be improved if a more holistic approach to osteoarthritis management were considered," he said.

All 494 patients had primary, unilateral knee replacements secondary to osteoarthritis. Their mean age was 65, 65% were women, and almost half were obese.

The patients filled out several surveys before their operations, including WOMAC and other pain and function scales plus the Profile of Mood States (POMS) fatigue scale, the Knee injury and Osteoarthritis Outcome Score (KOOS) sports and recreation scale, and the Hospital Anxiety and Depression Scale (HADS). They also pointed out on a homunculus diagram which joints were causing trouble.

Almost half (46%) reported pain on most days in four or more joints in addition to their operative knee. The nonoperative knee was a problem for 57%, elbows/wrists/hands were problematic for 49%, ankles/feet for 36%, the back for 31%, shoulders for 29%, hips for 25%, and neck for 22%. Just 15% said only their operative knee was symptomatic.

A year after their operation, patients took the surveys again. Those with back problems tended to see less improvement in fatigue at 1 year. Those with ankle or foot arthritis – in addition to diminished returns on pain and function – also saw less improvement than others in depression and sports and recreation scores.

The congress was sponsored by the Osteoarthritis Research Society International. Dr. Perruccio said he had no relevant financial disclosures. The work was funded by the Canadian Institutes of Health Research.

* Correction, 10/21/11: The original headline of this story, "Knee Replacement Worsens Arthritis in Other Joints," misrepresented the findings of this study. The headline has been revised.

SAN DIEGO – It’s not unusual for total knee replacement patients to have arthritis in other joints, and it negatively impacts surgery outcomes, Toronto researchers have found.

In their study, 420 of 494 knee replacement patients (85%) reported problems in at least one other joint. Those with foot or ankle arthritis had a significantly reduced chance of achieving an MCID (Minimally Clinically Important Difference) on postoperative WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) pain and function scores (odds ratio pain 0.32, 95% confidence interval 0.185-0.544; OR function 0.53, 95% CI 0.303, 0.940).

Patients who reported neck problems also had reduced odds of achieving an MCID on physical function WOMAC scores (OR 0.37, 95% CI 0.183, 0.726).

"It’s not surprising that ankles and feet [were] significant. [They] impact activities for which lower-extremity joints are involved. How the upper extremities are associated here, in particular the neck, is unclear," said lead investigator Anthony Perruccio, Ph.D., an epidemiologist and research scientist at the Toronto Western Research Institute.

Because patients with neck problems also saw less improvement in fatigue, anxiety, depression, and pain, there may also be a mental health component, he said.

Whatever the case, the lesson is to treat the whole patient, not just the knee. Referrals to other types of providers are appropriate, including physiotherapists and mental health counselors as needed, said Dr. Perruccio.

"There’s more than just the one joint that’s involved here. Outcomes could be improved if a more holistic approach to osteoarthritis management were considered," he said.

All 494 patients had primary, unilateral knee replacements secondary to osteoarthritis. Their mean age was 65, 65% were women, and almost half were obese.

The patients filled out several surveys before their operations, including WOMAC and other pain and function scales plus the Profile of Mood States (POMS) fatigue scale, the Knee injury and Osteoarthritis Outcome Score (KOOS) sports and recreation scale, and the Hospital Anxiety and Depression Scale (HADS). They also pointed out on a homunculus diagram which joints were causing trouble.

Almost half (46%) reported pain on most days in four or more joints in addition to their operative knee. The nonoperative knee was a problem for 57%, elbows/wrists/hands were problematic for 49%, ankles/feet for 36%, the back for 31%, shoulders for 29%, hips for 25%, and neck for 22%. Just 15% said only their operative knee was symptomatic.

A year after their operation, patients took the surveys again. Those with back problems tended to see less improvement in fatigue at 1 year. Those with ankle or foot arthritis – in addition to diminished returns on pain and function – also saw less improvement than others in depression and sports and recreation scores.

The congress was sponsored by the Osteoarthritis Research Society International. Dr. Perruccio said he had no relevant financial disclosures. The work was funded by the Canadian Institutes of Health Research.

* Correction, 10/21/11: The original headline of this story, "Knee Replacement Worsens Arthritis in Other Joints," misrepresented the findings of this study. The headline has been revised.

SAN DIEGO – Patients with severe pain in the first 3 months after total knee replacement have worse pain and function outcomes at 1 and 2 years, and are less satisfied with the procedure, Boston researchers have found.

Because of that, severe pain after the operation "is something that we ought to be intervening on," said lead investigator Dr. Jeffrey N. Katz, professor of medicine and orthopedic surgery at Harvard Medical School, Boston.

Depressed, catastrophizing patients and those in severe pain before the operation are all at risk for severe pain afterward. Using cognitive-behavioral therapy and optimizing antidepressant dosages and pain control can help, both before and after the operation, Dr. Katz said at the World Congress on Osteoarthritis.

Also, "people might consider operating sooner," before pain becomes severe, he said.

Of the approximately 600,000 total knee replacements in the United States every year, about 15% of patients have severe pain after the operation, but until now, it wasn’t known "whether that portends poor outcomes over time," Dr. Katz said.

His team found that it did, at least in the 622 unilateral, primary, total knee replacement patients in their study. Overall, 62% were aged older than 65 years, 58% were women, 35% had a body mass index greater than 30 kg/m²; and about half had two or more comorbidities.

Their mean preoperative function score on the WOMAC (Western Ontario and McMaster Universities) osteoarthritis index was 47, and their mean preoperative WOMAC pain score was 41 (with 100 being the best score on the WOMAC index and 0 the worst possible).

Following the surgery, 15% of the patients had WOMAC pain scores lower than 50 at 3 months, which indicated severe pain. Dr. Katz and his team compared these patients with the other 85%.

The patients with severe pain at 3 months had mean WOMAC function scores of about 60 at both the 1- and 2-year follow-up. The 85% of patients without severe pain had function scores in the mid-70s at both points.

Similarly, the severe pain group had WOMAC pain scores in the mid-60s at both 1 and 2 years. The other patients had mean WOMAC scores in the mid-80s at both points.

About 60% in the severe pain group said they couldn’t walk five blocks at both 1 and 2 years. Among those without severe pain, about 40% said that couldn’t walk five blocks at both points.

Finally, about a quarter of patients in the severe pain group were dissatisfied with their surgery at both 1 and 2 years afterward. About 5% of patients without severe postsurgical pain were dissatisfied with their operation at 1 year and about 3% were dissatisfied at 2 years. All the results were statistically significant (P less than .001).

The patients came from 12 referral centers in the United States, the United Kingdom, and Australia. The study did not capture the reasons for the pain, the problems with implants (if any), or the patients’ psychiatric histories.

Dr. Katz said that the 5-year findings appear to be similar to the 1- and 2-year results, but there weren’t enough data to include them in the analysis.

The congress was sponsored by the Osteoarthritis Research Society International. The study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The data used in the analysis came from a multicenter, prospective cohort study sponsored by implant maker Stryker Corp. about a decade ago. Dr. Katz said he has no disclosures.

SAN DIEGO – Patients with severe pain in the first 3 months after total knee replacement have worse pain and function outcomes at 1 and 2 years, and are less satisfied with the procedure, Boston researchers have found.

Because of that, severe pain after the operation "is something that we ought to be intervening on," said lead investigator Dr. Jeffrey N. Katz, professor of medicine and orthopedic surgery at Harvard Medical School, Boston.

Depressed, catastrophizing patients and those in severe pain before the operation are all at risk for severe pain afterward. Using cognitive-behavioral therapy and optimizing antidepressant dosages and pain control can help, both before and after the operation, Dr. Katz said at the World Congress on Osteoarthritis.

Also, "people might consider operating sooner," before pain becomes severe, he said.

Of the approximately 600,000 total knee replacements in the United States every year, about 15% of patients have severe pain after the operation, but until now, it wasn’t known "whether that portends poor outcomes over time," Dr. Katz said.

His team found that it did, at least in the 622 unilateral, primary, total knee replacement patients in their study. Overall, 62% were aged older than 65 years, 58% were women, 35% had a body mass index greater than 30 kg/m²; and about half had two or more comorbidities.

Their mean preoperative function score on the WOMAC (Western Ontario and McMaster Universities) osteoarthritis index was 47, and their mean preoperative WOMAC pain score was 41 (with 100 being the best score on the WOMAC index and 0 the worst possible).

Following the surgery, 15% of the patients had WOMAC pain scores lower than 50 at 3 months, which indicated severe pain. Dr. Katz and his team compared these patients with the other 85%.

The patients with severe pain at 3 months had mean WOMAC function scores of about 60 at both the 1- and 2-year follow-up. The 85% of patients without severe pain had function scores in the mid-70s at both points.

Similarly, the severe pain group had WOMAC pain scores in the mid-60s at both 1 and 2 years. The other patients had mean WOMAC scores in the mid-80s at both points.

About 60% in the severe pain group said they couldn’t walk five blocks at both 1 and 2 years. Among those without severe pain, about 40% said that couldn’t walk five blocks at both points.

Finally, about a quarter of patients in the severe pain group were dissatisfied with their surgery at both 1 and 2 years afterward. About 5% of patients without severe postsurgical pain were dissatisfied with their operation at 1 year and about 3% were dissatisfied at 2 years. All the results were statistically significant (P less than .001).

The patients came from 12 referral centers in the United States, the United Kingdom, and Australia. The study did not capture the reasons for the pain, the problems with implants (if any), or the patients’ psychiatric histories.

Dr. Katz said that the 5-year findings appear to be similar to the 1- and 2-year results, but there weren’t enough data to include them in the analysis.

The congress was sponsored by the Osteoarthritis Research Society International. The study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The data used in the analysis came from a multicenter, prospective cohort study sponsored by implant maker Stryker Corp. about a decade ago. Dr. Katz said he has no disclosures.

SAN DIEGO – Patients with severe pain in the first 3 months after total knee replacement have worse pain and function outcomes at 1 and 2 years, and are less satisfied with the procedure, Boston researchers have found.

Because of that, severe pain after the operation "is something that we ought to be intervening on," said lead investigator Dr. Jeffrey N. Katz, professor of medicine and orthopedic surgery at Harvard Medical School, Boston.

Depressed, catastrophizing patients and those in severe pain before the operation are all at risk for severe pain afterward. Using cognitive-behavioral therapy and optimizing antidepressant dosages and pain control can help, both before and after the operation, Dr. Katz said at the World Congress on Osteoarthritis.

Also, "people might consider operating sooner," before pain becomes severe, he said.

Of the approximately 600,000 total knee replacements in the United States every year, about 15% of patients have severe pain after the operation, but until now, it wasn’t known "whether that portends poor outcomes over time," Dr. Katz said.

His team found that it did, at least in the 622 unilateral, primary, total knee replacement patients in their study. Overall, 62% were aged older than 65 years, 58% were women, 35% had a body mass index greater than 30 kg/m²; and about half had two or more comorbidities.

Their mean preoperative function score on the WOMAC (Western Ontario and McMaster Universities) osteoarthritis index was 47, and their mean preoperative WOMAC pain score was 41 (with 100 being the best score on the WOMAC index and 0 the worst possible).

Following the surgery, 15% of the patients had WOMAC pain scores lower than 50 at 3 months, which indicated severe pain. Dr. Katz and his team compared these patients with the other 85%.

The patients with severe pain at 3 months had mean WOMAC function scores of about 60 at both the 1- and 2-year follow-up. The 85% of patients without severe pain had function scores in the mid-70s at both points.

Similarly, the severe pain group had WOMAC pain scores in the mid-60s at both 1 and 2 years. The other patients had mean WOMAC scores in the mid-80s at both points.

About 60% in the severe pain group said they couldn’t walk five blocks at both 1 and 2 years. Among those without severe pain, about 40% said that couldn’t walk five blocks at both points.

Finally, about a quarter of patients in the severe pain group were dissatisfied with their surgery at both 1 and 2 years afterward. About 5% of patients without severe postsurgical pain were dissatisfied with their operation at 1 year and about 3% were dissatisfied at 2 years. All the results were statistically significant (P less than .001).

The patients came from 12 referral centers in the United States, the United Kingdom, and Australia. The study did not capture the reasons for the pain, the problems with implants (if any), or the patients’ psychiatric histories.

Dr. Katz said that the 5-year findings appear to be similar to the 1- and 2-year results, but there weren’t enough data to include them in the analysis.

The congress was sponsored by the Osteoarthritis Research Society International. The study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The data used in the analysis came from a multicenter, prospective cohort study sponsored by implant maker Stryker Corp. about a decade ago. Dr. Katz said he has no disclosures.

SAN DIEGO – Separating an osteoarthritic knee joint for 2 months – that is, stretching the top of the tibia away from the base of the femur and holding the bones in place with pins set into an external fixation frame – stimulates the joint to produce new cartilage, thereby reducing pain and improving function for at least 2 years, according to findings from a small European pilot study.

The 20 patients in the trial were all facing knee replacement due to osteoarthritis (OA); the technique, known as knee joint distraction, has postponed surgery for 2 years and counting in the subjects. The hope is the patients will never need an artificial knee, according to senior investigator Dr. Floris Lafeber, a professor of experimental rheumatology at the University Medical Center Utrecht (the Netherlands).

Their minimum joint space width increased from a baseline mean of 1.0 mm to 1.8 mm at 2 years. Patients started the trial with, on average, about 22% of their subchondral bone denuded; that dropped to about 8% at 2 years.

In short, there was an "astonishing increase in cartilage volume," Dr. Lafeber said at the World Congress on Osteoarthritis, which was sponsored by the Osteoarthritis Research Society International.

Meanwhile, total WOMAC (Western Ontario and McMaster Universities) osteoarthritis index scores increased from about 45% at baseline to about 78% at 2 years, with improvements in WOMAC pain, function, and stiffness subscales. Visual Analog Scale pain scores improved from 73 at baseline to 28 at 2 years. The results were statistically significant.

The technique, which had been used in the past for ankle OAs, "looks very promising" for osteoarthritic knees, Dr. Lafeber said. The 1 year results have been previously published (Ann. Rheum. Dis. 2011;70:1441-6; Internal Medicine News, August 2011, p. 22).

His team will next pit knee distraction against total knee replacement and osteotomy in two randomized trials. The researchers will keep tracking the original 20 patients as well. "We are now having follow-up of the first patients for more than 4 years, and no prostheses are placed yet," Dr. Lafeber said.

The researchers plan "more sophisticated MRIs to look at the quality of the cartilage," although the increased joint space on weight-bearing x-rays suggests mechanical competence. Biomarker analysis also suggests "the quality of the cartilage has a hyaline aspect," according to Dr. Lafeber.

The 20 patients’ average age was 49 years; 11 were women. All had end-stage, unilateral knee OA with severe pain and cartilage damage. Patients with major problems in both knees were excluded from the study.

In a variation of the Ilizarov procedure, a tube with internal coil springs was placed on each side of the patients’ osteoarthritic knees, bridging the joints. Joints were then distracted to 5 mm over a few days. Full weight bearing was allowed. The tubes and pins were removed after 2 months.

The theory is that temporarily unloading the knee prevents additional wear and tear and allows cartilage to start repairing itself.

Pin sites became infected in 17 of the 20 patients, and were treated with local and oral antibiotics. Dr. Lafeber said he and his colleagues hope that technique refinements will reduce the infection rate.

Dr. Lafeber said he had no disclosures. The work was supported by the Dutch Arthritis Association.

SAN DIEGO – Separating an osteoarthritic knee joint for 2 months – that is, stretching the top of the tibia away from the base of the femur and holding the bones in place with pins set into an external fixation frame – stimulates the joint to produce new cartilage, thereby reducing pain and improving function for at least 2 years, according to findings from a small European pilot study.

The 20 patients in the trial were all facing knee replacement due to osteoarthritis (OA); the technique, known as knee joint distraction, has postponed surgery for 2 years and counting in the subjects. The hope is the patients will never need an artificial knee, according to senior investigator Dr. Floris Lafeber, a professor of experimental rheumatology at the University Medical Center Utrecht (the Netherlands).

Their minimum joint space width increased from a baseline mean of 1.0 mm to 1.8 mm at 2 years. Patients started the trial with, on average, about 22% of their subchondral bone denuded; that dropped to about 8% at 2 years.

In short, there was an "astonishing increase in cartilage volume," Dr. Lafeber said at the World Congress on Osteoarthritis, which was sponsored by the Osteoarthritis Research Society International.

Meanwhile, total WOMAC (Western Ontario and McMaster Universities) osteoarthritis index scores increased from about 45% at baseline to about 78% at 2 years, with improvements in WOMAC pain, function, and stiffness subscales. Visual Analog Scale pain scores improved from 73 at baseline to 28 at 2 years. The results were statistically significant.

The technique, which had been used in the past for ankle OAs, "looks very promising" for osteoarthritic knees, Dr. Lafeber said. The 1 year results have been previously published (Ann. Rheum. Dis. 2011;70:1441-6; Internal Medicine News, August 2011, p. 22).

His team will next pit knee distraction against total knee replacement and osteotomy in two randomized trials. The researchers will keep tracking the original 20 patients as well. "We are now having follow-up of the first patients for more than 4 years, and no prostheses are placed yet," Dr. Lafeber said.

The researchers plan "more sophisticated MRIs to look at the quality of the cartilage," although the increased joint space on weight-bearing x-rays suggests mechanical competence. Biomarker analysis also suggests "the quality of the cartilage has a hyaline aspect," according to Dr. Lafeber.

The 20 patients’ average age was 49 years; 11 were women. All had end-stage, unilateral knee OA with severe pain and cartilage damage. Patients with major problems in both knees were excluded from the study.

In a variation of the Ilizarov procedure, a tube with internal coil springs was placed on each side of the patients’ osteoarthritic knees, bridging the joints. Joints were then distracted to 5 mm over a few days. Full weight bearing was allowed. The tubes and pins were removed after 2 months.

The theory is that temporarily unloading the knee prevents additional wear and tear and allows cartilage to start repairing itself.

Pin sites became infected in 17 of the 20 patients, and were treated with local and oral antibiotics. Dr. Lafeber said he and his colleagues hope that technique refinements will reduce the infection rate.

Dr. Lafeber said he had no disclosures. The work was supported by the Dutch Arthritis Association.

SAN DIEGO – Separating an osteoarthritic knee joint for 2 months – that is, stretching the top of the tibia away from the base of the femur and holding the bones in place with pins set into an external fixation frame – stimulates the joint to produce new cartilage, thereby reducing pain and improving function for at least 2 years, according to findings from a small European pilot study.

The 20 patients in the trial were all facing knee replacement due to osteoarthritis (OA); the technique, known as knee joint distraction, has postponed surgery for 2 years and counting in the subjects. The hope is the patients will never need an artificial knee, according to senior investigator Dr. Floris Lafeber, a professor of experimental rheumatology at the University Medical Center Utrecht (the Netherlands).

Their minimum joint space width increased from a baseline mean of 1.0 mm to 1.8 mm at 2 years. Patients started the trial with, on average, about 22% of their subchondral bone denuded; that dropped to about 8% at 2 years.

In short, there was an "astonishing increase in cartilage volume," Dr. Lafeber said at the World Congress on Osteoarthritis, which was sponsored by the Osteoarthritis Research Society International.

Meanwhile, total WOMAC (Western Ontario and McMaster Universities) osteoarthritis index scores increased from about 45% at baseline to about 78% at 2 years, with improvements in WOMAC pain, function, and stiffness subscales. Visual Analog Scale pain scores improved from 73 at baseline to 28 at 2 years. The results were statistically significant.

The technique, which had been used in the past for ankle OAs, "looks very promising" for osteoarthritic knees, Dr. Lafeber said. The 1 year results have been previously published (Ann. Rheum. Dis. 2011;70:1441-6; Internal Medicine News, August 2011, p. 22).

His team will next pit knee distraction against total knee replacement and osteotomy in two randomized trials. The researchers will keep tracking the original 20 patients as well. "We are now having follow-up of the first patients for more than 4 years, and no prostheses are placed yet," Dr. Lafeber said.

The researchers plan "more sophisticated MRIs to look at the quality of the cartilage," although the increased joint space on weight-bearing x-rays suggests mechanical competence. Biomarker analysis also suggests "the quality of the cartilage has a hyaline aspect," according to Dr. Lafeber.

The 20 patients’ average age was 49 years; 11 were women. All had end-stage, unilateral knee OA with severe pain and cartilage damage. Patients with major problems in both knees were excluded from the study.

In a variation of the Ilizarov procedure, a tube with internal coil springs was placed on each side of the patients’ osteoarthritic knees, bridging the joints. Joints were then distracted to 5 mm over a few days. Full weight bearing was allowed. The tubes and pins were removed after 2 months.

The theory is that temporarily unloading the knee prevents additional wear and tear and allows cartilage to start repairing itself.

Pin sites became infected in 17 of the 20 patients, and were treated with local and oral antibiotics. Dr. Lafeber said he and his colleagues hope that technique refinements will reduce the infection rate.

Dr. Lafeber said he had no disclosures. The work was supported by the Dutch Arthritis Association.