The measurement of the strain of the anterior cruciate ligament

During arthroscoptic examination, surgeons can probe, feel and grossly determine its laxity. But, although a complete ACL tear can be diagnosed by probing, the apparently intact but partially injured ligament is more difficult to evaluate. In this study, the authors developed an instrument that could quantitatively and less-invasively measure the strain of the ACL in vivo, and evaluated its feasibility. The results are follows; statistically, the strains measured by this instrument were different significantly between each classified ACL groups according to their laxity, with no difference in comparison with conventional diagnostic methods. Furthermore, the laxity of the ligament could be observed objectively, at the same time, more easily and less invasively. The data from this study can be used to evaluate apparently intact but partially injured borderline cases. And it would be useful in studying the biomechanical properties of the knee joint