Effects of cyclic loading on vibroarthrographic signals in computer-controlled knee movement: a cadaver study

This study involved arthroscopic creation of intra-articular pathology in cadaver knee joints to determine the effects of cyclic loading on vibroarthrographic (VAG) signals and to test the hypothesis that cartilage roughness or cartilage loss is correlated with VAG signal power and frequency. A cadaver model was used in which a compute-controlled quadriceps pull resulted in controlled knee extension and flexion at rates and ranges similar to those established in our in vivo vibration recording protocols. Specifically, each knee was put through several extension-flexion cyclic series at a joint angular velocity of 90° per second. Cartilage lesions were introduced arthroscopically in the patello-femoral joint between these series. Results indicate that the averaged root mean squared value and the averaged mean frequency of VAG signals of arthroscopically-created lesions are significantly higher than those of arthroscopically-normal knees, indicating that VAG may be a useful predictor of cartilage loss under these conditions.