[Stability after capsular ligament surgery of the knee joint]

Post-operative checks of 57 cases of anterio-medial knee instability (II and III degree) were carried out over a period of 1-4 years after operation. "Subjective knee stability" was documented on three levels in a questionnaire as not "giving way". "Objective knee stability" was evaluated by measuring 30 degree anterior drawer displacement using the KT 1000 instrument. Strength of the thigh muscles of both legs for different power parameters under isokinetic load was measured with the Cybex II instrument system. No significant correlation between subjective perception of knee instability and instrumented measured anterior drawer displacement could be shown in a T-test. Individuals with higher "objective stability" or higher "subjective stability" level had both generally stronger tight muscle parameters, specially for knee extension. Most of our interest had the group of individuals assumed "subjective stable" but having quite a large anterior drawer displacement phenomena like ACL deficit knee. This group is characterized by higher 10 degree power parameters for knee extension and flexion and lower H/Q-quotient. This is supposed to be indication to functional adaptation of the neuro-muscular system to altered biomechanic situation after ACL disruption or reconstruction. Electromyographic studies should follow to test this hypothesis.