Lever-Test Accuracy in Detecting Anterior Cruciate Ligament (ACL) Tears: A Single Institution Experience

Abstract

Background One of the most often damaged ligaments in the knee is the anterior cruciate ligament (ACL). With the increased occurrence of ACL injuries, there is a greater need for clinical diagnostics to rule in or rule out a suspected rupture. The Lever Test, a novel clinical tool for diagnosing ACL rupture, has been presented, with preliminary trials indicating encouraging results. Methods This is a prospective, blinded, diagnostic accuracy study. The aim of this study was to evaluate the accuracy of the Lever Test and other common clinical tests (Anterior Drawer Test, Lachman Test, Pivot Shift Test) for diagnosing ACL injuries. The study enrolled 23 patients who had knee pain, instability, and locking symptoms. The clinical tests were performed on the patients in supine position before, during, and after anesthesia. The results of the clinical tests were compared with MRI findings to determine the sensitivity of each test. Results The patients consisted of 17 men and six women, with a mean age of 30.4±9.95 years. 18 patients had complete tears, four had partial tears, and one had intact ACL damage. 10 (44%) complained in the right knee, 13 (56%) in the left knee, and two (9%) had a generalized ligamentous laxity. 21 (91%) complained of giving away, 22 (96%) complained of knee pain, and 10 (43%) complained of locking of the knee. On the ipsilateral leg examination, pre-operative positivity of Lever Sign was 44%, Lachman 83%, and Anterior Drawer 67%. After being given anesthesia, test positivity rates were 44% for Lever Sign and 56% for Pivot Shift. Post-operative positivity of Lever Sign was 17%, Lachman 39%, and Anterior Drawer 35%. Mcnemar test p values were significant for the difference of positivity anterior drawer test (p=0.002) and were not significant on Lever Sign (p=0.7) and Lachman tests (p=0.13). Correlation analysis showed a weak but not statistically significant interrater reliability between MRI findings and Lever Sign (p=0.846) (Kappa= 0.2). On the contralateral leg examination, the pre-operative positivity of Lever Sign was 9%, Lachman 17%, and Anterior Drawer 22% Conclusion The study suggests that the Lever Test has lower accuracy than other clinical tests when comparing the results of tests with MRI findings. As a result, Lever Test should be used in combination with other clinical tests to accurately rule out suspected ACL injuries.