Anterior cruciate ligament replacement: comparison of bone-patellar tendon-bone grafts with two-strand hamstring grafts. A prospective, randomized study.

BACKGROUND: The purpose of this investigation was to evaluate replacement of a torn anterior cruciate ligament with either a bone-patellar tendon-bone autograft or a two-strand semitendinosus-gracilis autograft to compare the results of clinical testing, patient satisfaction, activity level, functional status, and muscle strength.

METHODS: Fifty-six patients with a torn anterior cruciate ligament were enrolled in a prospective, randomized, controlled study. Twenty-eight underwent reconstruction with a bone-patellar tendon-bone autograft, and twenty-eight were treated with a two-strand semitendinosus-gracilis autograft. Patients were followed for an average of thirty-nine months (range, thirty-six to fifty-seven months). At the time of final follow-up, twenty-two patients in each group were evaluated in terms of clinical test findings, patient satisfaction, activity level, functional status, and isokinetic muscle strength.

RESULTS: The objective outcome of replacement of the torn anterior cruciate ligament with a bone-patellar tendon-bone graft was superior to that obtained with a two-strand semitendinosus-gracilis graft. At the three-year follow-up interval, the patients in whom a hamstring graft had been used had an average of 4.4 mm of increased anterior knee laxity compared with the laxity of the contralateral, normal knee, whereas the patients in whom a bone-patellar tendon-bone graft had been used had an average of 1.1 mm of increased knee laxity. Fourteen percent (three) of the twenty-two patients with a hamstring graft had a mild pivot shift, and 27% (six) had a moderate pivot shift. Only 14% (three) of the twenty-two patients with a bone-patellar tendon-bone graft had a mild pivot shift, and none had a moderate pivot shift. At the same follow-up interval, the patients in whom a hamstring graft had been used had significantly lower peak knee-flexion strength than those who had a bone-patellar tendon-bone graft (p = 0.039). In contrast, the two treatments produced similar outcomes in terms of patient satisfaction, activity level, and knee function (ability to perform a one-legged hop, bear weight, squat, climb stairs, run in place, and duckwalk).

CONCLUSIONS: After three years of follow-up, the objective results of anterior cruciate ligament replacement with a bone-patellar tendon-bone autograft were superior to those of replacement with a two-strand semitendinosus-gracilis graft with regard to knee laxity, pivot-shift grade, and strength of the knee flexor muscles. However, the two groups had comparable results in terms of patient satisfaction, activity level, and knee function.