DEVELOPMENT, VALIDITY & RELIABILITY OF LACHMANN-O-METER TO DETECT ANTERIOR CRUCIATE LIGAMENT LAXITY IN A SAW BONE MODEL: A NEW PORTABLE, AUTOMATED ATHROMETER

We developed an arthrometer to detect ACL laxity that are automated, portable, user friendly and sensitive to detect ACL laxity called Lachman-O-Meter. This study is to assess the efficiency of the newly developed Lachman-O-Meter in detecting ACL laxity in a saw knee bone model in comparable to Lachman test. This was a pre-clinical, study on a saw bone knee models representing different grading of Lachman test; three button, two button and zero button knee model. Examiners were blinded and performed Lachman test on each saw bone model and were asked to grade it as soft end point, firm end point or negative Lachman test. Then, the examiner used Lachman-O-Meter on the saw bone model and record the finding. Criterion validity were performed using correlation analysis between the results of Lachman-O-Meter and the Lachman test. The sensitivity was 100% , specificity of 80% , positive predictive value of 90.9 %, and negative predictive value of 100%, in detecting ACL laxity with firm and soft end point. In zero button model, examiner able to identify the ACL laxity using Lachman-O-Meter, with 90% accuracy in identifying Lachman test with soft end point, (r= 0.80, 95% CI: 0.29–1.22, p = <0.001). In two button model, examiner able to identify the ACL laxity using Lachman-O-Meter, with 100% accuracy in identifying Lachman test with firm end point, (r= 1, CI: 0.29–1.22, p = <0.001). Lachman-O-Meter is an efficient tool to be used in the diagnosis of different degrees of ACL laxity with high sensitivity and specificity, and excellent inter and intra-rater reliability