Studies on the effect of posterior cruciate ligament (PCL) injury on muscle performance have demonstrated that the normal PCL accommodates sensory nerve endings with capabilities that provide the central nervous system with information about characteristics of movement and position-related stretches of the PCL. Concerning the effect of PCL injury on performance of the quadriceps and hamstrings, there is disagreement in the literature. If there is an effect in the PCL-deficient knee, it is not as simple as that in the anterior cruciate ligament (ACL)-deficient knee. Electromyographic studies have demonstrated that the gastrocnemius muscle is significantly activated during walking and isokinetic motion in the involved knee, as compared with the uninvolved knee. Results of a gait-analytic study suggested that there are significant differences in gait cycle between PCL-deficient and normal knees. These phenomena might be part of the compensatory mechanism in PCL-deficient knees, but the data on the effect of PCL injury on muscle performance remain insufficient at the present time.
Kazunori Yasuda and Harukazu Tohyama are with the Section of Sports Medicine, Department of Medical Bioengineering, at Hokkaido University School of Medicine, Sapporo, Japan. Masayuki Inoue is with the Department of Orthopaedic Surgery, NTT Higashi-Nippon Sapporo General Hospital, Sapporo, Japan.