Hamstring/quadriceps strength ratios in knees with medial collateral ligament insufficiency. Isokinetic and isometric results and their relation to patients' long-term recovery.

The purpose of this study was to investigate the peak torque and total work hamstring/quadriceps strength ratios (HQ-ratios) of 25 knees with medial collateral ligament (MCL) insufficiency and to find out the possible relation between different HQ-ratios and the long-term outcome of the patients. The isokinetic (speed 60 and 180 degrees/sec) and isometric muscle strengths were measured by a Cybex II dynamometer. Three standardized knee scoring scales were used to determine the subjective, clinical, and radiological outcome of the knees with MCL insufficiency. All tests showed great interpersonal variation in HQ-ratios even in the healthy knees (range from 23% to 183%). The average HQ-ratios between the uninjured and injured legs did not differ significantly from each other (range from 40% to 82%). The mean peak torques and total work of hamstrings as well as of quadriceps were slightly, but not significantly lower in the injured leg than on the uninjured side. The follow-up scores did not differ significantly between patient groups with low (less than or equal to 50%), optimal (50-80%), or high (greater than or equal to 80%) absolute HQ-ratios of the MCL insufficient knee. However, in every test the scores were significantly better for patients with an HQ-ratio difference of less than or equal to 15% between the injured and the uninjured side than for those with a clear difference (greater than 15%). The findings suggest that the HQ-ratio is a patient-specific parameter and that any general recommendation on its optimal value is difficult to give.(ABSTRACT TRUNCATED AT 250 WORDS)