Analysis of proprioception in the posterior cruciate ligament-deficient knee.

The purpose of this study was to demonstrate loss of proprioception with posterior cruciate ligament (PCL) deficiency. Eight patients with isolated PCL-deficient knees were examined to determine whether or not the proprioceptive function of the knee joint was affected or impaired by the previous tear of the PCL. The patients were examined for perception of passive movement of the knee joint using a motorized apparatus which extended or flexed the patient's knee at a rate of 0.5 deg/s in a randomized sequence. The patient's normal contralateral knee was used as a control. This study demonstrated a significant difference in proprioception in the patient's PCL-deficient knee. All eight PCL-deficient knees clearly demonstrated slower perception of passive movement when compared with the contralateral normal knee. Injuries to the PCL resulting in impaired proprioception may play a role in knee instability, further damage and ultimately the degenerative changes frequently seen in the long-term follow-up of PCL-deficient knees.