CHANGES IN MUSCLE STRENGTH PROPERTIES CAUSED BY HARVESTING OF AUTOGENOUS SEMITENDINOSUS TENDON FOR RECONSTRUCTION OF CONTRALATERAL ANTERIORCRUCIATE LIGAMENT

A prospective study was conducted of how the muscle strength of the do nor knee is affected by harvesting of the autogenous semitendinosus te ndon (St) for use as a substitute graft material in cruciate ligament reconstruction. There were 25 patients from whom only the St was harve sted from the contralateral (i.e., healthy/donor) knee. Using a Biodex System II (Biodex, New York, NY), the strength of the donor knee was measured during both extension and flexion, both before and 12 months after the tendon harvesting procedure. A comparative study was made of the preharvest and postharvest values for the peak torque and peak to rque angle in the isokinetic contraction. There were no statistically significant differences between the preharvest and postharvest peak to rque values of the donor knee. However, the peak torque angle decrease d significantly after the tendon harvest; the range of the mean decrea se was from 11.7 degrees to 15.0 degrees. This indicates that there wa s a change to a small flexion angle (P < .05). After the tendon harves t, regardless of the applied angular velocity, more than 80% of the ca ses showed a change of torque curve shape in which there was no peak i n the latter half, and the position of the peak was shifted to the lef t. In conclusion, the results of this study indicate that harvesting o f the autogenous St does not affect the peak torque, but the peak torq ue angle during flexion of the donor knee is reduced.