Grading ACL Laxity: Testing Only the Involved Knee Versus a Side-to-Side Comparison of Both Knees

Background and Purpose. Following a knee injury, one of the most important tests during a clinician\u27s examination is testing for anterior cruciate ligament (ACL) laxity. This study was performed to determine if there was a clinical significance in establishing a baseline with the uninvolved knee prior to testing the involved, and whether the Lachman ACL laxity test yields similar results to an instrumented testing device. Methods. Knee subjects were obtained via convenience sampling. Subjects (n =20), between the ages of 22 and 34 years participated in the study. Groups often subjects were tested with the KT -1000 knee ligament arthrometer by a physical therapist. The following day, those subjects were examined for ACL laxity by three physical therapists performing the Lachman test. Results. The Spearman rank correlation results found only Rater 1 had a good strength of association with the KT -1000 results, which occurred for both the unilateral and bilateral tests. The strength of association appeared to increase for both Rater 1 and Rater 3 when performing the bilateral Lachman tests, though not significantly. Discussion and Conclusion. Experienced orthopedic clinicians may place different emphases on the components of the Lachman test for ACL laxity. Performing the Lachman test on both knees of a subject, rather than unilaterally, did not consistently improve a therapist\u27s accuracy of ACL assessment. The Lachman ACL laxity test yielded different results than the KT -1000 test when assessing knee stability