Abstract des Autors

We have developed a device to measure the drawer at the knee joint. With the corresponding method, it is possible to measure the drawer under functional conditions. The purposes of our studies were to investigate the influence of a repaired ACL-injury and the influence of a proprioceptive training on the functional stability of the knee joint. In our investigations we induced an anterior drawer while the subjects were standing upright. The force, the knee joint angle and the EMGs of hamstrings and quadriceps were recorded. With our new device the anteroposterior shift of the tibia was measured. The muscle function was measured with the EMG. In the first study, the stability of the injured and the non injured leg of ACL deficient subjects after reconstruction was measured and compared with one leg of healthy subjects of a control group. In the second study, healthy subjects were measured before and after four weeks of proprioceptive training. Several differences between the injured leg on one hand and the healthy leg and the legs of the control group on the other hand could be detected, though the ACL was reconstructed and the injury was completely rehabilitated. Especially the reflex-latency of the knee stabilising muscles of the injured legs were significantly prolonged. In the longitudinal study, the stiffness of the knee joint was up to 60% higher after training than before. Simultaneously, the IEMGs of the knee extensors were significantly reduced 30-90 ms after the drawer was induced. The additional gain in joint stiffness in anterior direction seems to be a result of reduced activity of the knee extensors rather than a result of increased activity of the knee flexors. This increase in efficiency can be interpreted as a result of improved proprioception. After training, the subjects were able to recognise the direction of the destabilisation better than before. Verf.-Referat