Hamstring strength recovery after hamstring tendon harvest for anterior cruciate ligament reconstruction: a comparison between graft types

Abstract

Purpose: The purpose of this study was to investigate hamstring strength after harvest of 1 or 2 hamstring tendons for anterior cruciate ligament reconstruction.

Methods: We recruited 50 individuals who had returned to regular sporting activity to participate in a comparative study at a mean of 32.5 months after anterior cruciate ligament reconstructive surgery (30 in semitendinosus-gracilis group and 20 in semitendinosus group). Isokinetic hamstring strength (at 60 degrees/s and 180 degrees/s with the peak torque and torque produced at 60 degrees, 90 degrees, and 105 degrees of knee flexion recorded) and isometric hamstring strength (at 30 degrees, 90 degrees, and 105 degrees of knee flexion) were measured, and the standing knee flexion angle was used to evaluate functional hamstring strength recovery.

Results: No significant differences between the groups were found in any of the isometric or isokinetic strength measures or in the standing knee flexion angle. No relation was found between the standing knee flexion angle and the isometric hamstring strength results obtained at 105 degrees of knee flexion (r(2) = 0.034).

Conclusions: These findings show that the choice of hamstring tendon graft-that is, semitendinosus alone or semitendinosus and gracilis-is unlikely to significantly influence postoperative hamstring strength outcomes in athletes returning to sports postoperatively. Both graft choices showed strength deficits of between 3% and 27% compared with the nonoperated limb, indicating that hamstring strength deficits persist despite successful completion of rehabilitation. The results also show that the standing knee flexion angle should not be used as a surrogate clinical measure of hamstring strength.

Level of evidence: Level III, retrospective comparative study.