Characteristics of the isokinetic performance of patients with injured cruciate ligaments.

The torques of the quadriceps muscle in patients with cruciate ligament injuries were evaluated under isokinetic contraction. There were 30 patients with anterior cruciate ligament injuries, 19 with posterior cruciate ligament injuries, and 30 controls. The torques of concentric and eccentric contractions in anterior cruciate ligament-injured knees showed a significant difference from those in the uninjured sides at extension angles of less than 45 degrees, yet the values of the peak torques for concentric and eccentric contractions were the same as those for the uninjured sides. The torques of concentric and eccentric contractions in posterior cruciate ligament-injured knees showed a significant difference from the uninjured sides at flexion angles of more than 36 degrees. The peak torques for concentric and eccentric contraction also showed a significant difference from the uninjured sides. The concentric and eccentric peak torque angles of the injured knees were similar to those of the uninjured sides in all subjects. The ratios of eccentric to concentric peak torque of the contralateral knees in the anterior cruciate ligament-injured groups did not show a significant difference from those of the controls. The evaluation of the biomechanical change in these categories is of great advantage in determining proper methods of treatment and rehabilitation.