A Quantitative Measurement System of Endpoint during Lachman test with Force Sensor

Lachman test is one of manual tests for examining the anterior cruciate ligament (ACL). An examiner discreminates an injured degree of the ACL by feeling finger stress. Some measurement devices for Lachman test have been developed. However, these devices aim to analyze not the stress but a motion of the knee joint. Therefore, we set the goal of this study to develop a measurement system for the finger stress with force sensor during Lachman test. In the experiment, the developed system was applied to twelve healthy knees of six subjects by a beginner, and one injured and one healthy knee of two subjects by an expert. In the results, the maximum force of "endpoint" during Lachman test was analyzed. The variation of inter-subjects was larger than intra-subjects. Future works are to improve the finger force sensors, and to apply more subjects, so that the system could classify an examiner into a skill level.