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- Reliable data are scarce regarding the accuracy of physical diagnostic tests in diagnosing anterior cruciate ligament ruptures in primary care.
- The pivot shift test has a favorable positive predictive value, and the Lachman test has a good negative predictive value. The anterior drawer test is of unproven benefit in diagnosing rupture of the anterior cruciate ligament (ACL).
- Although of limited predictive value, the history and physical examination, coupled with patient preference and physical demands, should form the basis for further investigation of possible ACL rupture.
Objective: This systematic review summarizes the evidence on the accuracy of tests for assessing ACL ruptures of the knee.
Search strategy A computerized search of MEDLINE (1966–2003) and EMBASE (1980–2003) with additional reference tracking.
Selection criteria Articles included were written in English, French, German, or Dutch, and addressed the accuracy of at least 1 physical diagnostic test for ACL rupture, using arthrotomy, arthroscopy, or magnetic resonance imaging as the gold standard.
Data collection and analysis: Two reviewers independently selected studies, assessed the methodological quality, and abstracted data using a standardized protocol. We calculated sensitivity, specificity, and likelihood ratios for each test and summary estimates, when appropriate and possible.
Main results: Seventeen studies met the inclusion criteria. None assessed the index test and reference test independently (with blinding), and all but 2 displayed verification bias. Study results were heterogeneous. The pivot shift test seems to have favorable positive predictive value, and the Lachman test has good negative predictive value. The anterior drawer test is of unproven value.
Conclusions: Reliable data are rare regarding the accuracy of physical diagnostic tests for ACL ruptures, especially in a primary care setting. For the time being, history taking and physical examination, albeit of limited use, should be considered with individual patient demands to provide the basis for further evaluation.
To evaluate possible rupture of the anterior cruciate ligament (ACL), family physicians rely on the history and physical examination and primarily 3 diagnostic assessments: the anterior drawer test, the Lachman test, and the pivot shift test.1-3 Preliminary findings from these tests, coupled with patient preference and physical demands, help select those who may need further work-up with arthroscopy or magnetic resonance imaging (MRI).4
We summarize the evidence for the diagnostic accuracy of physical diagnostic tests in assessing ACL ruptures of the knee.
If a patient’s physical demands are low, one might proceed with a trial of conservative therapy (especially when Lachman’s test is negative), which has shown to be favorable for selected patients.5 However, when a patient has high demands (as is the case with athletes), more advanced diagnostic tests (eg, MRI) seem to be indicated, irrespective of the findings of physical examination.
Methods
Selection of studies
A computerized literature search of MEDLINE (from 1966 to February 14, 2003) and EMBASE (1980 to February 14, 2003) was conducted to identify articles written in English, French, German, or Dutch. Key words were the medical subject headings “knee injuries,”knee joint,” and “knee,” and the text word “knee.” This set was combined with a set consisting of the main headings “joint instability” and “anterior cruciate ligament,” and the text words “laxity,” “instability,” “cruciate,” and “effusion.”
Finally, the results of these strategies were combined with a validated search strategy for the identification of diagnostic studies using the subject headings “sensitivity and specificity” (exploded), “physical examination” and “not (animal not [human and animal])” and the text words “sensitivit$,” “specificit$,” “false positive,” “false negative,” “accuracy,” and “screening,”6 supplemented with the text words “physical examination” and “clinical examination.” Also, the cited references of included publications were examined.
Studies were selected by 2 reviewers independently. Studies were eligible for inclusion if they addressed the accuracy of at least 1 physical diagnostic test for the assessment of ACL ruptures of the knee, and used arthrotomy, arthroscopy, or MRI as the gold standard.
Assessment of methodological quality and data abstraction
The methodological quality of the selected studies was assessed and data were abstracted by 2 reviewers independently. Quality assessment was accomplished with a checklist adapted from Irwig and colleagues7 and the Cochrane Methods Group on Systematic Review of Screening and Diagnostic Tests.8 (Table W1 and Table W1 cont.).
Statistical analysis
Statistical analysis was performed9 with a strategy adapted from Midgette and colleagues.10 The method consists of estimating a summary receiver operating characteristic (SROC) curve by metaregression, and exploring heterogeneity by adding study characteristics and study validity items to the regression model (a full description of this strategy is available online as Appendix A).7-11
We performed an additional analysis according to a bivariate random effects model that accounts for heterogeneity of both sensitivity and specificity simultaneously, reflected in the width of the 95% confidence intervals.12,13
The summary estimates of sensitivity and specificity were used to calculate the predictive value of a positive (PV+) and negative test result (PV–) for circumstances with varying prevalences of ACL ruptures. When summary estimates of both sensitivity and specificity could not be calculated, the summary estimate of sensitivity and the accompanying specificity, estimated from the SROC curve, were used to calculate predictive values.
Results
Selection of studies
The literature search revealed a total of 1090 potentially eligible studies, 17 of which were selected.14-30 Two reports pertained to the same study,15,16 and 1 additional study was found by reference tracking.2 Thus, a total of 17 studies met the selection criteria.
Methodological quality and study characteristics
No study measured the index test (ie, the object of study) and reference standard independently (with blinding). Patients whose physical test results were abnormal were more likely to undergo the gold standard test—a factor that inflates sensitivity and decreases specificity. This verification bias was present in all but 2 studies.15,27 No study was performed in a primary care setting.
A detailed description of the characteristics and methodological quality of the 17 included studies is available online (Appendix B, Table W2-1, Table W2-2, Table W2-3, and Table W3).
Accuracy of ACL tests
Details of the process of selecting studies for further meta-analysis are presented online (Appendix C).
Diagnostic accuracy of the ACL tests is shown in Table 1. Significant heterogeneity of sensitivity and specificity was seen with all ACL tests, and no significant subgroups were detected for any of the tests. The power of metaregression analysis, however, was low due to the small number of available studies (4 to 6) and because some characteristics exhibited no variation.
Anterior drawer test. Correlation of sensitivity and specificity for the anterior drawer test was positive (6 studies); thus, no SROC curve was estimated. Sensitivity of the anterior drawer test was 0.18–0.92, and specificity 0.78–0.98. According to the bivariate random effects model, the pooled sensitivity was 0.62 (95% confidence interval [CI], 0.42–0.78) and the pooled specificity was 0.88 (95% CI, 0.83–0.92) ( Figure 1A ).
TABLE 1
Diagnostic accuracy of the anterior drawer sign, Lachman test, and pivot shift test
| First author | Type of ACL rupture | N | Prevalence | Sn | Sp | LR+ | LR– |
|---|---|---|---|---|---|---|---|
| Anterior drawer sign | |||||||
| Hardaker25 | Partial + complete | 132 | 0.77 | 0.18 | — | — | — |
| Tonino19*† | Partial + complete | 52 | 0.58 | 0.27 | 0.98 | 12.6 | 0.7 |
| Rubinstein28 | “ACL-deficient” | 39 | 0.23 | (0.76)§ | (0.86)§ | — | — |
| Boeree26* | Not specified | 203 | 0.29 | 0.56 | 0.92 | 6.7 | 0.5 |
| Lee21* | Not specified | 79 | 0.29 | 0.77 | 0.99 | 87.9 | 0.2 |
| Richter29* | Not specified | 74 | 0.78 | 0.67 | 0.88 | 5.4 | 0.4 |
| SteinbrÜck22* | Not specified | 300 | 0.17 | 0.92 | 0.91 | 10.4 | 0.1 |
| Sandberg18*‡ | Not specified | 182 | 0.68 | 0.39 | 0.78 | 1.7 | 0.8 |
| Lachman test | |||||||
| Hardaker25 | Partial + complete | 132 | 0.77 | 0.74 | — | — | — |
| Tonino19* | Partial + complete | 52 | 0.58 | 0.89 | 0.98 | 40.8 | 0.1 |
| Schwarz30*‡ | Partial + complete | 58 | 0.81 | 0.91 | 0.55 | 2.0 | 0.2 |
| Rubinstein28 | “ACL-deficient” | 39 | 0.23 | (0.96)§ | (1.00)§ | — | — |
| Boeree26* | Not specified | 203 | 0.29 | 0.63 | 0.90 | 6.5 | 0.4 |
| Lee21* | Not specified | 79 | 0.29 | 0.90 | 0.99 | 102.1 | 0.1 |
| Richter29*‡ | Not specified | 74 | 0.78 | 0.93 | 0.88 | 7.4 | 0.1 |
| SteinbrÜck22* | Not specified | 300 | 0.17 | 0.86 | 0.95 | 17.9 | 0.1 |
| Cooperman24 | Not specified | 32 | 0.41 | (0.65)║ | (0.42)║ | — | — |
| Pivot shift test | |||||||
| Hardaker25 | Partial + complete | 132 | 0.77 | 0.29 | — | — | — |
| Tonino19* | Partial + complete | 52 | 0.58 | 0.18 | 0.98 | 8.2 | 0.8 |
| Rubinstein28 | “ACL-deficient” | 39 | 0.23 | (0.93)§ | (0.89)§ | — | — |
| Boeree26* | Not specified | 203 | 0.29 | 0.31 | 0.97 | 8.8 | 0.7 |
| Richter29*†‡ | Not specified | 74 | 0.78 | 0.48 | 0.97 | 16.4 | 0.5 |
| SteinbrÜck22* | Not specified | 300 | 0.17 | 0.22 | 0.99 | 26.9 | 0.8 |
| * Study results used for meta-analysis | |||||||
| † 0.5 added to each cell of the 2x2 table | |||||||
| ‡ 2x2 table reconstructed | |||||||
| § Mean result of 5 orthopedic surgeons | |||||||
| ║ Sum of results of 2 physiotherapists | |||||||
| ACL, anterior cruciate ligament; Sn, sensitivity; Sp, specificity; LR+, positive likelihood ratio; LR–, negative likelihood ratio | |||||||
FIGURE 1
Sensitivity vs 1–specificity of the 3 tests
Scatterplots of sensitivity versus 1–specificity of A) the anterior drawer test (6 studies), B) the Lachman test (6 studies), and C) the pivot shift test (4 studies). Summary receiver operating characteristic curves and summary estimates of sensitivity and specificity (including 95% confidence intervals) are shown as appropriate.
Lachman test (Figure 2). The SROC curve of the Lachman test (6 studies) is shown in Figure 1B . Sensitivity ranged from 0.63 to 0.93, and specificity from 0.55 to 0.99. According to the bivariate random effects model the pooled sensitivity was 0.86 (95% CI, 0.76–0.92) and the pooled specificity was 0.91 (95% CI, 0.79–0.96).
Pivot shift test. The SROC curve of the pivot shift test (4 studies) is shown in Figure 1C . Sensitivity ranged from 0.18 to 0.48, and specificity from 0.97 to 0.99. Bivariate random effects pooling could not be performed; in this model 5 parameters must be estimated and only 4 studies were available.
Figure 3 shows the PV+ and PV– for all tests according to varying prevalences of ACL ruptures. The pivot shift test has the highest PV+ and the Lachman test the highest PV–. If the pivot shift test is positive, there is high probability of an ACL rupture, whereas a negative Lachman test rules out a rupture.
FIGURE 2
Lachman test
To perform the Lachman test, grasp the back of the proximal tibia posteriorly and place thumb over joint line anterolaterally. Pull the proximal tibia anteriorly and posteriorly, and compare sides for endpoint laxity.
FIGURE 3
Predictive value vs prevalence of positive and negative test results
Predictive value (posttest probability of presence of ACL rupture) vs prevalence (prior probability of presence of ACL rupture) of positive and negative test results of the anterior drawer test (sensitivity=0.62, specificity=0.88), Lachman test (sensitivity=0.86, specificity=0.91), and the pivot shift test (sensitivity=0.32, specificity=0.98).
DISCUSSION
We reviewed 17 studies that examined the accuracy of physical diagnostic tests for assessing ACL ruptures of the knee. Of those tests, the pivot shift test seems to have favorable positive predictive value, and the Lachman test good negative predictive value. The anterior drawer test is of unproven diagnostic value in this setting. In view of the potential biases in the original studies, however, the accuracy of the various ACL tests might be overestimated and the poor quality of the studies impede sound conclusions about the usefulness of the tests for daily practice. In addition, no study has been performed in primary care.
Because test characteristics may be influenced substantially by referral filters leading to spectrum bias,31 and because primary care physicians will be less experienced in performing these tests, the tests will presumably be less accurate in a primary care setting. Furthermore, the pivot shift test is very difficult to perform, making it less attractive for the average primary care physician.
Future research
Useful answers would be derived from sound research on the diagnostic accuracy of the various tests (determined for each test separately and for all tests jointly) combined with patient characteristics (eg, age, physical fitness, and functional demands) and elements of the medical history (eg, type of trauma and nature of the complaints). The emergence of MRI will facilitate this research. Relevance to clinical practice would be enhanced by an assessment of the effect of a correct diagnosis on the functional outcome of patients.
Acknowledgments
The authors thank Afina Glas, MD, and Professor Koos Zwinderman, PhD, for their statistical advice. We are much obliged to 1 of the referees for his/her useful suggestions.
Corresponding author
Rob J.P.M. Scholten, MD, PhD, Dutch Cochrane Centre, Department of Clinical Epidemiology and Biostatistics, J2-273, Academic Medical Center, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands. E-mail: [email protected].
1. Slocum DB, Larson RL. Rotatory instability of the knee. Its pathogenesis and a clinical test to demonstrate its presence. J Bone Joint Surg Am 1968;50:211-225.
2. Torg JS, Conrad W, Kalen V. Clinical diagnosis of anterior cruciate ligament instability in the athlete. Am J Sports Med 1976;4:84-93.
3. Galway HR, MacIntosh DL. The lateral pivot shift: a symptom and sign of anterior cruciate ligament insufficiency. Clin Orthop 1980;147:45-50.
4. Boeve BF, Davidson RA, Staab EV. Magnetic resonance imaging in the evaluation of knee injuries. South Med J 1991;84:1123-1127.
5. Buss DD, Min R, Skyhar M, Galinat B, Warren RF, Wickiewicz TL. Nonoperative treatment of acute anterior cruciate ligament injuries in a selected group of patients. Am J Sports Med 1995;23:160-165.
6. Devillè WLJM, Bezemer PD, Bouter LM. Publications on diagnostic test evaluation in family medicine journals: an optimal search strategy. J Clin Epidemiol 2000;53:65-69.
7. Irwig L, Macaskill P, Glasziou P, Fahey M. Meta-analytic methods for diagnostic test accuracy. J Clin Epidemiol 1995;48:119-130.
8. Cochrane Methods Group on Systematic Review of Screening and Diagnostic Tests: Recommended, Methods, updated 6 June 1996. Available at http://www.cochrane.de/cochrane/sadtdoc1.htm.
9. Scholten RJPM, Devillè WLJM, Opstelten W, Bijl D, van der Plas CG, Bouter LM. The accuracy of physical diagnostic tests for assessing meniscal lesions of the knee: a meta-analysis. J Fam Pract 2001;50:938-944.
10. Midgette AS, Stukel TA, Littenberg B. A meta-analytic method for summarizing diagnostic test performances: receiver-operating-characteristic-summary point estimates. Med Decis Making 1993;13:253-257.
11. Moses LE, Shapiro D, Littenberg B. Combining independent studies of a diagnostic test into a summary ROC curve: data-analytic approaches and some additional considerations. Stat Med 1993;12:1293-1316.
12. van Houwelingen JC, Zwinderman K, Stijnen T. A bivariate approach to meta-analysis. Stat Med. 1993;12:2272-2284.
13. van Houwelingen JC, Arends LR, Stijnen T. Advanced methods in meta-analysis: multivariate approach and meta-regression. Stat Med 2002;21:589-624.
14. Warren RF, Marshall JL. Injuries of the anterior cruciate and medial collateral ligaments of the knee. A retrospective analysis of clinical records—part I. Clin Orthop 1978;136:191-197.
15. Noyes FR, Bassett RW, Grood ES, Butler DL. Arthroscopy in acute traumatic hemarthrosis of the knee. Incidence of anterior cruciate tears and other injuries. J Bone Joint Surg 1980;62A:687-695.
16. Noyes FR, Paulos L, Mooar LA, Signer B. Knee sprains and acute knee hemarthrosis: misdiagnosis of anterior cruciate ligament tears. Phys Ther 1980;60:1596-1601.
17. Braunstein EM. Anterior cruciate ligament injuries: a comparison of arthrographic and physical diagnosis. AJR Am J Roentgenol 1982;138:423-425.
18. Sandberg R, Balkfors B, Henricson A, Westlin N. Stability tests in knee ligament injuries. Arch Orthop Trauma Surg 1986;106:5-7.
19. Tonino AJ, Huy J, Schaafsma J. The diagnostic accuracy of knee testing in the acutely injured knee. Initial examination versus examination under anaesthesia with arthroscopy. Acta Orthop Belg 1986;52:479-487.
20. Harilainen A. Evaluation of knee instability in acute liga-mentous injuries. Ann Chir Gynaecol 1987;76:269-273.
21. Lee JK, Yao L, Phelps CT, Wirth CR, Czajka J, Lozman J. Anterior cruciate ligament tears: MR imaging compared with arthroscopy and clinical tests. Radiology 1988;166:861-864.
22. SteinbrÜck K, Wiehmann JC. Examination of the knee joint. The value of clinical findings in arthroscopic control [in German]. Z Orthop Ihre Grenzgeb 1988;126:289-295.
23. Anderson AF, Lipscomb AB. Preoperative instrumented testing of anterior and posterior knee laxity. Am J Sports Med 1989;17:387-392.
24. Cooperman JM, Riddle DL, Rothstein JM. Reliability and validity of judgments of the integrity of the anterior cruci-ate ligament of the knee using the Lachman’s test. Phys Ther 1990;70:225-233.
25. Hardaker WT Jr, Garrett WE Jr, Bassett FH 3d. Evaluation of acute traumatic hemarthrosis of the knee joint. South Med J 1990;83:640-644.
26. Boeree NR, Ackroyd CE. Assessment of the menisci and cruciate ligaments: an audit of clinical practice. Injury 1991;22:291-294.
27. al-Duri Z. Relation of the fibular head sign to other signs of anterior cruciate ligament insufficiency. A follow-up letter to the editor. Clin Orthop 1992;275:220-225.
28. Rubinstein RA Jr, Shelbourne KD, McCarroll JR, VanMeter CD, Rettig AC. The accuracy of the clinical examination in the setting of posterior cruciate ligament injuries. Am J Sports Med 1994;22:550-557.
29. Richter J, David A, Pape HG, Ostermann PA, Muhr G. Diagnosis of acute rupture of the anterior cruciate liga-ment. Value of ultrasonic in addition to clinical examination [in German]. Unfallchirurg 1996;99:124-129.
30. Schwarz W, Hagelstein J, Minholz R, Schierlinger M, Danz B, Gerngross H. Manual ultrasound of the knee joint. A general practice method for diagnosis of fresh rupture of the anterior cruciate ligament [in German]. Unfallchirurg 1997;100:280-285.
31. Knottnerus JA, Leffers P. The influence of referral patterns on the characteristics of diagnostic tests. J Clin Epidemiol 1992;45:1143-1154.
- Reliable data are scarce regarding the accuracy of physical diagnostic tests in diagnosing anterior cruciate ligament ruptures in primary care.
- The pivot shift test has a favorable positive predictive value, and the Lachman test has a good negative predictive value. The anterior drawer test is of unproven benefit in diagnosing rupture of the anterior cruciate ligament (ACL).
- Although of limited predictive value, the history and physical examination, coupled with patient preference and physical demands, should form the basis for further investigation of possible ACL rupture.
Objective: This systematic review summarizes the evidence on the accuracy of tests for assessing ACL ruptures of the knee.
Search strategy A computerized search of MEDLINE (1966–2003) and EMBASE (1980–2003) with additional reference tracking.
Selection criteria Articles included were written in English, French, German, or Dutch, and addressed the accuracy of at least 1 physical diagnostic test for ACL rupture, using arthrotomy, arthroscopy, or magnetic resonance imaging as the gold standard.
Data collection and analysis: Two reviewers independently selected studies, assessed the methodological quality, and abstracted data using a standardized protocol. We calculated sensitivity, specificity, and likelihood ratios for each test and summary estimates, when appropriate and possible.
Main results: Seventeen studies met the inclusion criteria. None assessed the index test and reference test independently (with blinding), and all but 2 displayed verification bias. Study results were heterogeneous. The pivot shift test seems to have favorable positive predictive value, and the Lachman test has good negative predictive value. The anterior drawer test is of unproven value.
Conclusions: Reliable data are rare regarding the accuracy of physical diagnostic tests for ACL ruptures, especially in a primary care setting. For the time being, history taking and physical examination, albeit of limited use, should be considered with individual patient demands to provide the basis for further evaluation.
To evaluate possible rupture of the anterior cruciate ligament (ACL), family physicians rely on the history and physical examination and primarily 3 diagnostic assessments: the anterior drawer test, the Lachman test, and the pivot shift test.1-3 Preliminary findings from these tests, coupled with patient preference and physical demands, help select those who may need further work-up with arthroscopy or magnetic resonance imaging (MRI).4
We summarize the evidence for the diagnostic accuracy of physical diagnostic tests in assessing ACL ruptures of the knee.
If a patient’s physical demands are low, one might proceed with a trial of conservative therapy (especially when Lachman’s test is negative), which has shown to be favorable for selected patients.5 However, when a patient has high demands (as is the case with athletes), more advanced diagnostic tests (eg, MRI) seem to be indicated, irrespective of the findings of physical examination.
Methods
Selection of studies
A computerized literature search of MEDLINE (from 1966 to February 14, 2003) and EMBASE (1980 to February 14, 2003) was conducted to identify articles written in English, French, German, or Dutch. Key words were the medical subject headings “knee injuries,”knee joint,” and “knee,” and the text word “knee.” This set was combined with a set consisting of the main headings “joint instability” and “anterior cruciate ligament,” and the text words “laxity,” “instability,” “cruciate,” and “effusion.”
Finally, the results of these strategies were combined with a validated search strategy for the identification of diagnostic studies using the subject headings “sensitivity and specificity” (exploded), “physical examination” and “not (animal not [human and animal])” and the text words “sensitivit$,” “specificit$,” “false positive,” “false negative,” “accuracy,” and “screening,”6 supplemented with the text words “physical examination” and “clinical examination.” Also, the cited references of included publications were examined.
Studies were selected by 2 reviewers independently. Studies were eligible for inclusion if they addressed the accuracy of at least 1 physical diagnostic test for the assessment of ACL ruptures of the knee, and used arthrotomy, arthroscopy, or MRI as the gold standard.
Assessment of methodological quality and data abstraction
The methodological quality of the selected studies was assessed and data were abstracted by 2 reviewers independently. Quality assessment was accomplished with a checklist adapted from Irwig and colleagues7 and the Cochrane Methods Group on Systematic Review of Screening and Diagnostic Tests.8 (Table W1 and Table W1 cont.).
Statistical analysis
Statistical analysis was performed9 with a strategy adapted from Midgette and colleagues.10 The method consists of estimating a summary receiver operating characteristic (SROC) curve by metaregression, and exploring heterogeneity by adding study characteristics and study validity items to the regression model (a full description of this strategy is available online as Appendix A).7-11
We performed an additional analysis according to a bivariate random effects model that accounts for heterogeneity of both sensitivity and specificity simultaneously, reflected in the width of the 95% confidence intervals.12,13
The summary estimates of sensitivity and specificity were used to calculate the predictive value of a positive (PV+) and negative test result (PV–) for circumstances with varying prevalences of ACL ruptures. When summary estimates of both sensitivity and specificity could not be calculated, the summary estimate of sensitivity and the accompanying specificity, estimated from the SROC curve, were used to calculate predictive values.
Results
Selection of studies
The literature search revealed a total of 1090 potentially eligible studies, 17 of which were selected.14-30 Two reports pertained to the same study,15,16 and 1 additional study was found by reference tracking.2 Thus, a total of 17 studies met the selection criteria.
Methodological quality and study characteristics
No study measured the index test (ie, the object of study) and reference standard independently (with blinding). Patients whose physical test results were abnormal were more likely to undergo the gold standard test—a factor that inflates sensitivity and decreases specificity. This verification bias was present in all but 2 studies.15,27 No study was performed in a primary care setting.
A detailed description of the characteristics and methodological quality of the 17 included studies is available online (Appendix B, Table W2-1, Table W2-2, Table W2-3, and Table W3).
Accuracy of ACL tests
Details of the process of selecting studies for further meta-analysis are presented online (Appendix C).
Diagnostic accuracy of the ACL tests is shown in Table 1. Significant heterogeneity of sensitivity and specificity was seen with all ACL tests, and no significant subgroups were detected for any of the tests. The power of metaregression analysis, however, was low due to the small number of available studies (4 to 6) and because some characteristics exhibited no variation.
Anterior drawer test. Correlation of sensitivity and specificity for the anterior drawer test was positive (6 studies); thus, no SROC curve was estimated. Sensitivity of the anterior drawer test was 0.18–0.92, and specificity 0.78–0.98. According to the bivariate random effects model, the pooled sensitivity was 0.62 (95% confidence interval [CI], 0.42–0.78) and the pooled specificity was 0.88 (95% CI, 0.83–0.92) ( Figure 1A ).
TABLE 1
Diagnostic accuracy of the anterior drawer sign, Lachman test, and pivot shift test
| First author | Type of ACL rupture | N | Prevalence | Sn | Sp | LR+ | LR– |
|---|---|---|---|---|---|---|---|
| Anterior drawer sign | |||||||
| Hardaker25 | Partial + complete | 132 | 0.77 | 0.18 | — | — | — |
| Tonino19*† | Partial + complete | 52 | 0.58 | 0.27 | 0.98 | 12.6 | 0.7 |
| Rubinstein28 | “ACL-deficient” | 39 | 0.23 | (0.76)§ | (0.86)§ | — | — |
| Boeree26* | Not specified | 203 | 0.29 | 0.56 | 0.92 | 6.7 | 0.5 |
| Lee21* | Not specified | 79 | 0.29 | 0.77 | 0.99 | 87.9 | 0.2 |
| Richter29* | Not specified | 74 | 0.78 | 0.67 | 0.88 | 5.4 | 0.4 |
| SteinbrÜck22* | Not specified | 300 | 0.17 | 0.92 | 0.91 | 10.4 | 0.1 |
| Sandberg18*‡ | Not specified | 182 | 0.68 | 0.39 | 0.78 | 1.7 | 0.8 |
| Lachman test | |||||||
| Hardaker25 | Partial + complete | 132 | 0.77 | 0.74 | — | — | — |
| Tonino19* | Partial + complete | 52 | 0.58 | 0.89 | 0.98 | 40.8 | 0.1 |
| Schwarz30*‡ | Partial + complete | 58 | 0.81 | 0.91 | 0.55 | 2.0 | 0.2 |
| Rubinstein28 | “ACL-deficient” | 39 | 0.23 | (0.96)§ | (1.00)§ | — | — |
| Boeree26* | Not specified | 203 | 0.29 | 0.63 | 0.90 | 6.5 | 0.4 |
| Lee21* | Not specified | 79 | 0.29 | 0.90 | 0.99 | 102.1 | 0.1 |
| Richter29*‡ | Not specified | 74 | 0.78 | 0.93 | 0.88 | 7.4 | 0.1 |
| SteinbrÜck22* | Not specified | 300 | 0.17 | 0.86 | 0.95 | 17.9 | 0.1 |
| Cooperman24 | Not specified | 32 | 0.41 | (0.65)║ | (0.42)║ | — | — |
| Pivot shift test | |||||||
| Hardaker25 | Partial + complete | 132 | 0.77 | 0.29 | — | — | — |
| Tonino19* | Partial + complete | 52 | 0.58 | 0.18 | 0.98 | 8.2 | 0.8 |
| Rubinstein28 | “ACL-deficient” | 39 | 0.23 | (0.93)§ | (0.89)§ | — | — |
| Boeree26* | Not specified | 203 | 0.29 | 0.31 | 0.97 | 8.8 | 0.7 |
| Richter29*†‡ | Not specified | 74 | 0.78 | 0.48 | 0.97 | 16.4 | 0.5 |
| SteinbrÜck22* | Not specified | 300 | 0.17 | 0.22 | 0.99 | 26.9 | 0.8 |
| * Study results used for meta-analysis | |||||||
| † 0.5 added to each cell of the 2x2 table | |||||||
| ‡ 2x2 table reconstructed | |||||||
| § Mean result of 5 orthopedic surgeons | |||||||
| ║ Sum of results of 2 physiotherapists | |||||||
| ACL, anterior cruciate ligament; Sn, sensitivity; Sp, specificity; LR+, positive likelihood ratio; LR–, negative likelihood ratio | |||||||
FIGURE 1
Sensitivity vs 1–specificity of the 3 tests
Scatterplots of sensitivity versus 1–specificity of A) the anterior drawer test (6 studies), B) the Lachman test (6 studies), and C) the pivot shift test (4 studies). Summary receiver operating characteristic curves and summary estimates of sensitivity and specificity (including 95% confidence intervals) are shown as appropriate.
Lachman test (Figure 2). The SROC curve of the Lachman test (6 studies) is shown in Figure 1B . Sensitivity ranged from 0.63 to 0.93, and specificity from 0.55 to 0.99. According to the bivariate random effects model the pooled sensitivity was 0.86 (95% CI, 0.76–0.92) and the pooled specificity was 0.91 (95% CI, 0.79–0.96).
Pivot shift test. The SROC curve of the pivot shift test (4 studies) is shown in Figure 1C . Sensitivity ranged from 0.18 to 0.48, and specificity from 0.97 to 0.99. Bivariate random effects pooling could not be performed; in this model 5 parameters must be estimated and only 4 studies were available.
Figure 3 shows the PV+ and PV– for all tests according to varying prevalences of ACL ruptures. The pivot shift test has the highest PV+ and the Lachman test the highest PV–. If the pivot shift test is positive, there is high probability of an ACL rupture, whereas a negative Lachman test rules out a rupture.
FIGURE 2
Lachman test
To perform the Lachman test, grasp the back of the proximal tibia posteriorly and place thumb over joint line anterolaterally. Pull the proximal tibia anteriorly and posteriorly, and compare sides for endpoint laxity.
FIGURE 3
Predictive value vs prevalence of positive and negative test results
Predictive value (posttest probability of presence of ACL rupture) vs prevalence (prior probability of presence of ACL rupture) of positive and negative test results of the anterior drawer test (sensitivity=0.62, specificity=0.88), Lachman test (sensitivity=0.86, specificity=0.91), and the pivot shift test (sensitivity=0.32, specificity=0.98).
DISCUSSION
We reviewed 17 studies that examined the accuracy of physical diagnostic tests for assessing ACL ruptures of the knee. Of those tests, the pivot shift test seems to have favorable positive predictive value, and the Lachman test good negative predictive value. The anterior drawer test is of unproven diagnostic value in this setting. In view of the potential biases in the original studies, however, the accuracy of the various ACL tests might be overestimated and the poor quality of the studies impede sound conclusions about the usefulness of the tests for daily practice. In addition, no study has been performed in primary care.
Because test characteristics may be influenced substantially by referral filters leading to spectrum bias,31 and because primary care physicians will be less experienced in performing these tests, the tests will presumably be less accurate in a primary care setting. Furthermore, the pivot shift test is very difficult to perform, making it less attractive for the average primary care physician.
Future research
Useful answers would be derived from sound research on the diagnostic accuracy of the various tests (determined for each test separately and for all tests jointly) combined with patient characteristics (eg, age, physical fitness, and functional demands) and elements of the medical history (eg, type of trauma and nature of the complaints). The emergence of MRI will facilitate this research. Relevance to clinical practice would be enhanced by an assessment of the effect of a correct diagnosis on the functional outcome of patients.
Acknowledgments
The authors thank Afina Glas, MD, and Professor Koos Zwinderman, PhD, for their statistical advice. We are much obliged to 1 of the referees for his/her useful suggestions.
Corresponding author
Rob J.P.M. Scholten, MD, PhD, Dutch Cochrane Centre, Department of Clinical Epidemiology and Biostatistics, J2-273, Academic Medical Center, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands. E-mail: [email protected].
- Reliable data are scarce regarding the accuracy of physical diagnostic tests in diagnosing anterior cruciate ligament ruptures in primary care.
- The pivot shift test has a favorable positive predictive value, and the Lachman test has a good negative predictive value. The anterior drawer test is of unproven benefit in diagnosing rupture of the anterior cruciate ligament (ACL).
- Although of limited predictive value, the history and physical examination, coupled with patient preference and physical demands, should form the basis for further investigation of possible ACL rupture.
Objective: This systematic review summarizes the evidence on the accuracy of tests for assessing ACL ruptures of the knee.
Search strategy A computerized search of MEDLINE (1966–2003) and EMBASE (1980–2003) with additional reference tracking.
Selection criteria Articles included were written in English, French, German, or Dutch, and addressed the accuracy of at least 1 physical diagnostic test for ACL rupture, using arthrotomy, arthroscopy, or magnetic resonance imaging as the gold standard.
Data collection and analysis: Two reviewers independently selected studies, assessed the methodological quality, and abstracted data using a standardized protocol. We calculated sensitivity, specificity, and likelihood ratios for each test and summary estimates, when appropriate and possible.
Main results: Seventeen studies met the inclusion criteria. None assessed the index test and reference test independently (with blinding), and all but 2 displayed verification bias. Study results were heterogeneous. The pivot shift test seems to have favorable positive predictive value, and the Lachman test has good negative predictive value. The anterior drawer test is of unproven value.
Conclusions: Reliable data are rare regarding the accuracy of physical diagnostic tests for ACL ruptures, especially in a primary care setting. For the time being, history taking and physical examination, albeit of limited use, should be considered with individual patient demands to provide the basis for further evaluation.
To evaluate possible rupture of the anterior cruciate ligament (ACL), family physicians rely on the history and physical examination and primarily 3 diagnostic assessments: the anterior drawer test, the Lachman test, and the pivot shift test.1-3 Preliminary findings from these tests, coupled with patient preference and physical demands, help select those who may need further work-up with arthroscopy or magnetic resonance imaging (MRI).4
We summarize the evidence for the diagnostic accuracy of physical diagnostic tests in assessing ACL ruptures of the knee.
If a patient’s physical demands are low, one might proceed with a trial of conservative therapy (especially when Lachman’s test is negative), which has shown to be favorable for selected patients.5 However, when a patient has high demands (as is the case with athletes), more advanced diagnostic tests (eg, MRI) seem to be indicated, irrespective of the findings of physical examination.
Methods
Selection of studies
A computerized literature search of MEDLINE (from 1966 to February 14, 2003) and EMBASE (1980 to February 14, 2003) was conducted to identify articles written in English, French, German, or Dutch. Key words were the medical subject headings “knee injuries,”knee joint,” and “knee,” and the text word “knee.” This set was combined with a set consisting of the main headings “joint instability” and “anterior cruciate ligament,” and the text words “laxity,” “instability,” “cruciate,” and “effusion.”
Finally, the results of these strategies were combined with a validated search strategy for the identification of diagnostic studies using the subject headings “sensitivity and specificity” (exploded), “physical examination” and “not (animal not [human and animal])” and the text words “sensitivit$,” “specificit$,” “false positive,” “false negative,” “accuracy,” and “screening,”6 supplemented with the text words “physical examination” and “clinical examination.” Also, the cited references of included publications were examined.
Studies were selected by 2 reviewers independently. Studies were eligible for inclusion if they addressed the accuracy of at least 1 physical diagnostic test for the assessment of ACL ruptures of the knee, and used arthrotomy, arthroscopy, or MRI as the gold standard.
Assessment of methodological quality and data abstraction
The methodological quality of the selected studies was assessed and data were abstracted by 2 reviewers independently. Quality assessment was accomplished with a checklist adapted from Irwig and colleagues7 and the Cochrane Methods Group on Systematic Review of Screening and Diagnostic Tests.8 (Table W1 and Table W1 cont.).
Statistical analysis
Statistical analysis was performed9 with a strategy adapted from Midgette and colleagues.10 The method consists of estimating a summary receiver operating characteristic (SROC) curve by metaregression, and exploring heterogeneity by adding study characteristics and study validity items to the regression model (a full description of this strategy is available online as Appendix A).7-11
We performed an additional analysis according to a bivariate random effects model that accounts for heterogeneity of both sensitivity and specificity simultaneously, reflected in the width of the 95% confidence intervals.12,13
The summary estimates of sensitivity and specificity were used to calculate the predictive value of a positive (PV+) and negative test result (PV–) for circumstances with varying prevalences of ACL ruptures. When summary estimates of both sensitivity and specificity could not be calculated, the summary estimate of sensitivity and the accompanying specificity, estimated from the SROC curve, were used to calculate predictive values.
Results
Selection of studies
The literature search revealed a total of 1090 potentially eligible studies, 17 of which were selected.14-30 Two reports pertained to the same study,15,16 and 1 additional study was found by reference tracking.2 Thus, a total of 17 studies met the selection criteria.
Methodological quality and study characteristics
No study measured the index test (ie, the object of study) and reference standard independently (with blinding). Patients whose physical test results were abnormal were more likely to undergo the gold standard test—a factor that inflates sensitivity and decreases specificity. This verification bias was present in all but 2 studies.15,27 No study was performed in a primary care setting.
A detailed description of the characteristics and methodological quality of the 17 included studies is available online (Appendix B, Table W2-1, Table W2-2, Table W2-3, and Table W3).
Accuracy of ACL tests
Details of the process of selecting studies for further meta-analysis are presented online (Appendix C).
Diagnostic accuracy of the ACL tests is shown in Table 1. Significant heterogeneity of sensitivity and specificity was seen with all ACL tests, and no significant subgroups were detected for any of the tests. The power of metaregression analysis, however, was low due to the small number of available studies (4 to 6) and because some characteristics exhibited no variation.
Anterior drawer test. Correlation of sensitivity and specificity for the anterior drawer test was positive (6 studies); thus, no SROC curve was estimated. Sensitivity of the anterior drawer test was 0.18–0.92, and specificity 0.78–0.98. According to the bivariate random effects model, the pooled sensitivity was 0.62 (95% confidence interval [CI], 0.42–0.78) and the pooled specificity was 0.88 (95% CI, 0.83–0.92) ( Figure 1A ).
TABLE 1
Diagnostic accuracy of the anterior drawer sign, Lachman test, and pivot shift test
| First author | Type of ACL rupture | N | Prevalence | Sn | Sp | LR+ | LR– |
|---|---|---|---|---|---|---|---|
| Anterior drawer sign | |||||||
| Hardaker25 | Partial + complete | 132 | 0.77 | 0.18 | — | — | — |
| Tonino19*† | Partial + complete | 52 | 0.58 | 0.27 | 0.98 | 12.6 | 0.7 |
| Rubinstein28 | “ACL-deficient” | 39 | 0.23 | (0.76)§ | (0.86)§ | — | — |
| Boeree26* | Not specified | 203 | 0.29 | 0.56 | 0.92 | 6.7 | 0.5 |
| Lee21* | Not specified | 79 | 0.29 | 0.77 | 0.99 | 87.9 | 0.2 |
| Richter29* | Not specified | 74 | 0.78 | 0.67 | 0.88 | 5.4 | 0.4 |
| SteinbrÜck22* | Not specified | 300 | 0.17 | 0.92 | 0.91 | 10.4 | 0.1 |
| Sandberg18*‡ | Not specified | 182 | 0.68 | 0.39 | 0.78 | 1.7 | 0.8 |
| Lachman test | |||||||
| Hardaker25 | Partial + complete | 132 | 0.77 | 0.74 | — | — | — |
| Tonino19* | Partial + complete | 52 | 0.58 | 0.89 | 0.98 | 40.8 | 0.1 |
| Schwarz30*‡ | Partial + complete | 58 | 0.81 | 0.91 | 0.55 | 2.0 | 0.2 |
| Rubinstein28 | “ACL-deficient” | 39 | 0.23 | (0.96)§ | (1.00)§ | — | — |
| Boeree26* | Not specified | 203 | 0.29 | 0.63 | 0.90 | 6.5 | 0.4 |
| Lee21* | Not specified | 79 | 0.29 | 0.90 | 0.99 | 102.1 | 0.1 |
| Richter29*‡ | Not specified | 74 | 0.78 | 0.93 | 0.88 | 7.4 | 0.1 |
| SteinbrÜck22* | Not specified | 300 | 0.17 | 0.86 | 0.95 | 17.9 | 0.1 |
| Cooperman24 | Not specified | 32 | 0.41 | (0.65)║ | (0.42)║ | — | — |
| Pivot shift test | |||||||
| Hardaker25 | Partial + complete | 132 | 0.77 | 0.29 | — | — | — |
| Tonino19* | Partial + complete | 52 | 0.58 | 0.18 | 0.98 | 8.2 | 0.8 |
| Rubinstein28 | “ACL-deficient” | 39 | 0.23 | (0.93)§ | (0.89)§ | — | — |
| Boeree26* | Not specified | 203 | 0.29 | 0.31 | 0.97 | 8.8 | 0.7 |
| Richter29*†‡ | Not specified | 74 | 0.78 | 0.48 | 0.97 | 16.4 | 0.5 |
| SteinbrÜck22* | Not specified | 300 | 0.17 | 0.22 | 0.99 | 26.9 | 0.8 |
| * Study results used for meta-analysis | |||||||
| † 0.5 added to each cell of the 2x2 table | |||||||
| ‡ 2x2 table reconstructed | |||||||
| § Mean result of 5 orthopedic surgeons | |||||||
| ║ Sum of results of 2 physiotherapists | |||||||
| ACL, anterior cruciate ligament; Sn, sensitivity; Sp, specificity; LR+, positive likelihood ratio; LR–, negative likelihood ratio | |||||||
FIGURE 1
Sensitivity vs 1–specificity of the 3 tests
Scatterplots of sensitivity versus 1–specificity of A) the anterior drawer test (6 studies), B) the Lachman test (6 studies), and C) the pivot shift test (4 studies). Summary receiver operating characteristic curves and summary estimates of sensitivity and specificity (including 95% confidence intervals) are shown as appropriate.
Lachman test (Figure 2). The SROC curve of the Lachman test (6 studies) is shown in Figure 1B . Sensitivity ranged from 0.63 to 0.93, and specificity from 0.55 to 0.99. According to the bivariate random effects model the pooled sensitivity was 0.86 (95% CI, 0.76–0.92) and the pooled specificity was 0.91 (95% CI, 0.79–0.96).
Pivot shift test. The SROC curve of the pivot shift test (4 studies) is shown in Figure 1C . Sensitivity ranged from 0.18 to 0.48, and specificity from 0.97 to 0.99. Bivariate random effects pooling could not be performed; in this model 5 parameters must be estimated and only 4 studies were available.
Figure 3 shows the PV+ and PV– for all tests according to varying prevalences of ACL ruptures. The pivot shift test has the highest PV+ and the Lachman test the highest PV–. If the pivot shift test is positive, there is high probability of an ACL rupture, whereas a negative Lachman test rules out a rupture.
FIGURE 2
Lachman test
To perform the Lachman test, grasp the back of the proximal tibia posteriorly and place thumb over joint line anterolaterally. Pull the proximal tibia anteriorly and posteriorly, and compare sides for endpoint laxity.
FIGURE 3
Predictive value vs prevalence of positive and negative test results
Predictive value (posttest probability of presence of ACL rupture) vs prevalence (prior probability of presence of ACL rupture) of positive and negative test results of the anterior drawer test (sensitivity=0.62, specificity=0.88), Lachman test (sensitivity=0.86, specificity=0.91), and the pivot shift test (sensitivity=0.32, specificity=0.98).
DISCUSSION
We reviewed 17 studies that examined the accuracy of physical diagnostic tests for assessing ACL ruptures of the knee. Of those tests, the pivot shift test seems to have favorable positive predictive value, and the Lachman test good negative predictive value. The anterior drawer test is of unproven diagnostic value in this setting. In view of the potential biases in the original studies, however, the accuracy of the various ACL tests might be overestimated and the poor quality of the studies impede sound conclusions about the usefulness of the tests for daily practice. In addition, no study has been performed in primary care.
Because test characteristics may be influenced substantially by referral filters leading to spectrum bias,31 and because primary care physicians will be less experienced in performing these tests, the tests will presumably be less accurate in a primary care setting. Furthermore, the pivot shift test is very difficult to perform, making it less attractive for the average primary care physician.
Future research
Useful answers would be derived from sound research on the diagnostic accuracy of the various tests (determined for each test separately and for all tests jointly) combined with patient characteristics (eg, age, physical fitness, and functional demands) and elements of the medical history (eg, type of trauma and nature of the complaints). The emergence of MRI will facilitate this research. Relevance to clinical practice would be enhanced by an assessment of the effect of a correct diagnosis on the functional outcome of patients.
Acknowledgments
The authors thank Afina Glas, MD, and Professor Koos Zwinderman, PhD, for their statistical advice. We are much obliged to 1 of the referees for his/her useful suggestions.
Corresponding author
Rob J.P.M. Scholten, MD, PhD, Dutch Cochrane Centre, Department of Clinical Epidemiology and Biostatistics, J2-273, Academic Medical Center, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands. E-mail: [email protected].
1. Slocum DB, Larson RL. Rotatory instability of the knee. Its pathogenesis and a clinical test to demonstrate its presence. J Bone Joint Surg Am 1968;50:211-225.
2. Torg JS, Conrad W, Kalen V. Clinical diagnosis of anterior cruciate ligament instability in the athlete. Am J Sports Med 1976;4:84-93.
3. Galway HR, MacIntosh DL. The lateral pivot shift: a symptom and sign of anterior cruciate ligament insufficiency. Clin Orthop 1980;147:45-50.
4. Boeve BF, Davidson RA, Staab EV. Magnetic resonance imaging in the evaluation of knee injuries. South Med J 1991;84:1123-1127.
5. Buss DD, Min R, Skyhar M, Galinat B, Warren RF, Wickiewicz TL. Nonoperative treatment of acute anterior cruciate ligament injuries in a selected group of patients. Am J Sports Med 1995;23:160-165.
6. Devillè WLJM, Bezemer PD, Bouter LM. Publications on diagnostic test evaluation in family medicine journals: an optimal search strategy. J Clin Epidemiol 2000;53:65-69.
7. Irwig L, Macaskill P, Glasziou P, Fahey M. Meta-analytic methods for diagnostic test accuracy. J Clin Epidemiol 1995;48:119-130.
8. Cochrane Methods Group on Systematic Review of Screening and Diagnostic Tests: Recommended, Methods, updated 6 June 1996. Available at http://www.cochrane.de/cochrane/sadtdoc1.htm.
9. Scholten RJPM, Devillè WLJM, Opstelten W, Bijl D, van der Plas CG, Bouter LM. The accuracy of physical diagnostic tests for assessing meniscal lesions of the knee: a meta-analysis. J Fam Pract 2001;50:938-944.
10. Midgette AS, Stukel TA, Littenberg B. A meta-analytic method for summarizing diagnostic test performances: receiver-operating-characteristic-summary point estimates. Med Decis Making 1993;13:253-257.
11. Moses LE, Shapiro D, Littenberg B. Combining independent studies of a diagnostic test into a summary ROC curve: data-analytic approaches and some additional considerations. Stat Med 1993;12:1293-1316.
12. van Houwelingen JC, Zwinderman K, Stijnen T. A bivariate approach to meta-analysis. Stat Med. 1993;12:2272-2284.
13. van Houwelingen JC, Arends LR, Stijnen T. Advanced methods in meta-analysis: multivariate approach and meta-regression. Stat Med 2002;21:589-624.
14. Warren RF, Marshall JL. Injuries of the anterior cruciate and medial collateral ligaments of the knee. A retrospective analysis of clinical records—part I. Clin Orthop 1978;136:191-197.
15. Noyes FR, Bassett RW, Grood ES, Butler DL. Arthroscopy in acute traumatic hemarthrosis of the knee. Incidence of anterior cruciate tears and other injuries. J Bone Joint Surg 1980;62A:687-695.
16. Noyes FR, Paulos L, Mooar LA, Signer B. Knee sprains and acute knee hemarthrosis: misdiagnosis of anterior cruciate ligament tears. Phys Ther 1980;60:1596-1601.
17. Braunstein EM. Anterior cruciate ligament injuries: a comparison of arthrographic and physical diagnosis. AJR Am J Roentgenol 1982;138:423-425.
18. Sandberg R, Balkfors B, Henricson A, Westlin N. Stability tests in knee ligament injuries. Arch Orthop Trauma Surg 1986;106:5-7.
19. Tonino AJ, Huy J, Schaafsma J. The diagnostic accuracy of knee testing in the acutely injured knee. Initial examination versus examination under anaesthesia with arthroscopy. Acta Orthop Belg 1986;52:479-487.
20. Harilainen A. Evaluation of knee instability in acute liga-mentous injuries. Ann Chir Gynaecol 1987;76:269-273.
21. Lee JK, Yao L, Phelps CT, Wirth CR, Czajka J, Lozman J. Anterior cruciate ligament tears: MR imaging compared with arthroscopy and clinical tests. Radiology 1988;166:861-864.
22. SteinbrÜck K, Wiehmann JC. Examination of the knee joint. The value of clinical findings in arthroscopic control [in German]. Z Orthop Ihre Grenzgeb 1988;126:289-295.
23. Anderson AF, Lipscomb AB. Preoperative instrumented testing of anterior and posterior knee laxity. Am J Sports Med 1989;17:387-392.
24. Cooperman JM, Riddle DL, Rothstein JM. Reliability and validity of judgments of the integrity of the anterior cruci-ate ligament of the knee using the Lachman’s test. Phys Ther 1990;70:225-233.
25. Hardaker WT Jr, Garrett WE Jr, Bassett FH 3d. Evaluation of acute traumatic hemarthrosis of the knee joint. South Med J 1990;83:640-644.
26. Boeree NR, Ackroyd CE. Assessment of the menisci and cruciate ligaments: an audit of clinical practice. Injury 1991;22:291-294.
27. al-Duri Z. Relation of the fibular head sign to other signs of anterior cruciate ligament insufficiency. A follow-up letter to the editor. Clin Orthop 1992;275:220-225.
28. Rubinstein RA Jr, Shelbourne KD, McCarroll JR, VanMeter CD, Rettig AC. The accuracy of the clinical examination in the setting of posterior cruciate ligament injuries. Am J Sports Med 1994;22:550-557.
29. Richter J, David A, Pape HG, Ostermann PA, Muhr G. Diagnosis of acute rupture of the anterior cruciate liga-ment. Value of ultrasonic in addition to clinical examination [in German]. Unfallchirurg 1996;99:124-129.
30. Schwarz W, Hagelstein J, Minholz R, Schierlinger M, Danz B, Gerngross H. Manual ultrasound of the knee joint. A general practice method for diagnosis of fresh rupture of the anterior cruciate ligament [in German]. Unfallchirurg 1997;100:280-285.
31. Knottnerus JA, Leffers P. The influence of referral patterns on the characteristics of diagnostic tests. J Clin Epidemiol 1992;45:1143-1154.
1. Slocum DB, Larson RL. Rotatory instability of the knee. Its pathogenesis and a clinical test to demonstrate its presence. J Bone Joint Surg Am 1968;50:211-225.
2. Torg JS, Conrad W, Kalen V. Clinical diagnosis of anterior cruciate ligament instability in the athlete. Am J Sports Med 1976;4:84-93.
3. Galway HR, MacIntosh DL. The lateral pivot shift: a symptom and sign of anterior cruciate ligament insufficiency. Clin Orthop 1980;147:45-50.
4. Boeve BF, Davidson RA, Staab EV. Magnetic resonance imaging in the evaluation of knee injuries. South Med J 1991;84:1123-1127.
5. Buss DD, Min R, Skyhar M, Galinat B, Warren RF, Wickiewicz TL. Nonoperative treatment of acute anterior cruciate ligament injuries in a selected group of patients. Am J Sports Med 1995;23:160-165.
6. Devillè WLJM, Bezemer PD, Bouter LM. Publications on diagnostic test evaluation in family medicine journals: an optimal search strategy. J Clin Epidemiol 2000;53:65-69.
7. Irwig L, Macaskill P, Glasziou P, Fahey M. Meta-analytic methods for diagnostic test accuracy. J Clin Epidemiol 1995;48:119-130.
8. Cochrane Methods Group on Systematic Review of Screening and Diagnostic Tests: Recommended, Methods, updated 6 June 1996. Available at http://www.cochrane.de/cochrane/sadtdoc1.htm.
9. Scholten RJPM, Devillè WLJM, Opstelten W, Bijl D, van der Plas CG, Bouter LM. The accuracy of physical diagnostic tests for assessing meniscal lesions of the knee: a meta-analysis. J Fam Pract 2001;50:938-944.
10. Midgette AS, Stukel TA, Littenberg B. A meta-analytic method for summarizing diagnostic test performances: receiver-operating-characteristic-summary point estimates. Med Decis Making 1993;13:253-257.
11. Moses LE, Shapiro D, Littenberg B. Combining independent studies of a diagnostic test into a summary ROC curve: data-analytic approaches and some additional considerations. Stat Med 1993;12:1293-1316.
12. van Houwelingen JC, Zwinderman K, Stijnen T. A bivariate approach to meta-analysis. Stat Med. 1993;12:2272-2284.
13. van Houwelingen JC, Arends LR, Stijnen T. Advanced methods in meta-analysis: multivariate approach and meta-regression. Stat Med 2002;21:589-624.
14. Warren RF, Marshall JL. Injuries of the anterior cruciate and medial collateral ligaments of the knee. A retrospective analysis of clinical records—part I. Clin Orthop 1978;136:191-197.
15. Noyes FR, Bassett RW, Grood ES, Butler DL. Arthroscopy in acute traumatic hemarthrosis of the knee. Incidence of anterior cruciate tears and other injuries. J Bone Joint Surg 1980;62A:687-695.
16. Noyes FR, Paulos L, Mooar LA, Signer B. Knee sprains and acute knee hemarthrosis: misdiagnosis of anterior cruciate ligament tears. Phys Ther 1980;60:1596-1601.
17. Braunstein EM. Anterior cruciate ligament injuries: a comparison of arthrographic and physical diagnosis. AJR Am J Roentgenol 1982;138:423-425.
18. Sandberg R, Balkfors B, Henricson A, Westlin N. Stability tests in knee ligament injuries. Arch Orthop Trauma Surg 1986;106:5-7.
19. Tonino AJ, Huy J, Schaafsma J. The diagnostic accuracy of knee testing in the acutely injured knee. Initial examination versus examination under anaesthesia with arthroscopy. Acta Orthop Belg 1986;52:479-487.
20. Harilainen A. Evaluation of knee instability in acute liga-mentous injuries. Ann Chir Gynaecol 1987;76:269-273.
21. Lee JK, Yao L, Phelps CT, Wirth CR, Czajka J, Lozman J. Anterior cruciate ligament tears: MR imaging compared with arthroscopy and clinical tests. Radiology 1988;166:861-864.
22. SteinbrÜck K, Wiehmann JC. Examination of the knee joint. The value of clinical findings in arthroscopic control [in German]. Z Orthop Ihre Grenzgeb 1988;126:289-295.
23. Anderson AF, Lipscomb AB. Preoperative instrumented testing of anterior and posterior knee laxity. Am J Sports Med 1989;17:387-392.
24. Cooperman JM, Riddle DL, Rothstein JM. Reliability and validity of judgments of the integrity of the anterior cruci-ate ligament of the knee using the Lachman’s test. Phys Ther 1990;70:225-233.
25. Hardaker WT Jr, Garrett WE Jr, Bassett FH 3d. Evaluation of acute traumatic hemarthrosis of the knee joint. South Med J 1990;83:640-644.
26. Boeree NR, Ackroyd CE. Assessment of the menisci and cruciate ligaments: an audit of clinical practice. Injury 1991;22:291-294.
27. al-Duri Z. Relation of the fibular head sign to other signs of anterior cruciate ligament insufficiency. A follow-up letter to the editor. Clin Orthop 1992;275:220-225.
28. Rubinstein RA Jr, Shelbourne KD, McCarroll JR, VanMeter CD, Rettig AC. The accuracy of the clinical examination in the setting of posterior cruciate ligament injuries. Am J Sports Med 1994;22:550-557.
29. Richter J, David A, Pape HG, Ostermann PA, Muhr G. Diagnosis of acute rupture of the anterior cruciate liga-ment. Value of ultrasonic in addition to clinical examination [in German]. Unfallchirurg 1996;99:124-129.
30. Schwarz W, Hagelstein J, Minholz R, Schierlinger M, Danz B, Gerngross H. Manual ultrasound of the knee joint. A general practice method for diagnosis of fresh rupture of the anterior cruciate ligament [in German]. Unfallchirurg 1997;100:280-285.
31. Knottnerus JA, Leffers P. The influence of referral patterns on the characteristics of diagnostic tests. J Clin Epidemiol 1992;45:1143-1154.