Practice recommendations
- 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.
ABSTRACT
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