Atrophy of semitzendinosus and gracilis and flexor mechanism function after hamstring tendon harvest for anterior cruciate ligament reconstruction.

The cross-sectional areas of individual knee flexors and isokinetic flexion measurements were evaluated using computed tomography in 13 patients following semitendinosus and gracilis tendon harvest for anterior cruciate ligament reconstruction. The atrophy of tendon-dissected muscles demonstrated variance with two peaks: >70% and <50%. In three patients whose semitendinosus and gracilis muscles displayed areas <50% of the contralateral area, the cross-sectional area of the entire flexor group and work at >75 degrees of knee flexion was 88.1% and 51.9%, respectively. Therefore, hamstring tendon harvest can induce atrophy of tendon-dissected muscles and decrease flexor function.