Abstract
PURPOSE: Although there have been multiple clinical studies evaluating the accuracy of physical examination tests used to diagnose anterior cruciate ligament (ACL) injury, there are no data to date evaluating the accuracy of these tests in diagnosing re-injury after prior ACL reconstruction. We compared the sensitivity of three clinical tests - Lachman, anterior drawer, and pivot shift - in diagnosing initial ACL tears versus graft re-tears following a prior ACL reconstruction. METHODS: Twenty consecutive adult patients who had undergone primary ACL reconstruction and 20 consecutive adult patients who had undergone revision ACL reconstruction by a single surgeon at a tertiary care center from November 2011 to December 2017 were included in this study. RESULTS: The sensitivity of the Lachman test was 95.0% in diagnosing ACL tears in patients with native ACL versus 85.0% in patients with prior ACL reconstruction with allograft or autograft. The sensitivity of the anterior drawer test was 80.0% in patients with native ACL compared to 77.8% in patients with prior ACL reconstructions. The sensitivity of the pivot shift test could not be accurately assessed because pain and swelling prevented the physician from performing this test in most patients on their initial presentation to the clinic. CONCLUSIONS: This study suggests that a clinician may need to have a lower threshold to perform advanced imaging or diagnostic arthroscopic evaluation in a patient with prior ACL reconstruction with a suspected re-injury even if the physical examination tests are not immediately positive.