RELIABILITY AND VALIDITY OF JUDGMENTS OF THE INTEGRITY OF THE ANTERIOR CRUCIATE LIGAMENT OF THE KNEE USING THE LACHMAN TEST

This study assessed the intratester and intertester reliability and the validity of judgments of the integrity of the anterior cruciate ligament (ACL) based on the use of the Lachman's test. End-feel and tibial translation judgments made during the Lachman's test were also assessed. Patients with unilateral knee problems (N = 32), 13 of whom had documented ACL damage, were examined by two physical therapists and two orthopedic surgeons. Intratester Kappa values for whether the test was positive or negative were .44 for physical therapists, .60 for orthopedic surgeons, and .51 for all examiners. Intertester Kappa values were .69 for the therapists, .61 for the surgeons, and .42 for all examiners. The predictive value of a positive test was 47% for all examiners, whereas the predictive value of a negative test was 70%. Results indicate that Lachman's test judgments have limited reliability and may be more useful for predicting that a patient does not have an ACL injury than for predicting that the ACL is injured.