Prospective Comparative Study of ACL Reconstruction Between Using Hamstring Autograft and Soft Tissue Allograft

OBJECTIVES: Nowadays, two most commonly used grafts in the anterior cruciate ligament reconstruction are hamstring autograft and soft tissue allograft. Although the short-term clinical outcomes between two grafts were similar, only a few studies reported mid-term clinical outcomes. The purpose of this prospective study was to compare clinical outcomes of ACL reconstruction between using hamstring autograft and soft tissue allograft after mid-term follow-up. METHODS: One-hundred sixty-one patients that underwent ACL reconstruction (78 in the hamstring group and 83 in the fresh frozen soft tissue (tibialis anterior) allograft) were followed up for a minimum of 4 years.We compared clinical outcomes (IKDC scores and Tegner activity scores, and Lachman and pivot shift test findings) For the radiologic evaluation, we determined the degree of osteoarthritis based on Kellgren and Lawrence grade system at the time of final follow-up and compared the number of patient with progression of osteoarthritis more than grade I. The muscle strength and position sense using iso-kinetic dynamometer was compared at the final follow-up. We also compared complication rate including graft failures and infection during the follow-up. Among them, we did the 2(nd)-look arthroscopies to evaluate the partial rupture and extent of synovial coverage on grafts for 27 patients in each group. RESULTS: Stability results of the Lachman test, pivot-shift test, and knee joint laxity test failed to reveal any significant inter-group differences (P > 0.05). In the pivot-shift result, autograft group showed 7 cases of grade II and allograft group11 cases of grade II (p=0.09). The clinical outcomes, including Lysholm knee and Tegner activity scores, showed no significant differences between the two groups. Concerning osteoarthritis at the final follow-up, seven patients in the autograft group and eight patients in the allograft group progressed osteoarthritis more than one Kellgren-Lawrence grade at final follow-up (P=0.82). Moreover, extension and flexion muscle power deficits and position sense were similar in both groups. However, the complications were more in allograft group (5 failures and 2 infection in the allograft group and 2 failures and no infection in the autograft group) during the follow-up (P = 0.06). We observed the less partial rupture and better synovial coverage of graft in autograft than allograft under 2(nd) look arthroscopic findings. CONCLUSION: Although hamstring autograft and soft tissue allograft ACL reconstruction showed similar functional and radiological outcomes after mid-term follow-up, hamstring autograft group showed fewer complications including failure and better arthroscopic findings compared with soft tissue allograft group.