Summary

Comparison of Knee Stability and Synovial Fluid Alterations in Anterior Cruciate Ligament Reconstruction with Hamstring Autograft or Allograft

Abstract

This study attempted to compare the knee stability and the synovial fluid alterations in patients who under-went arthroscopic anterior cruciate ligament (ACL) reconstruction with either hamstring autograft or hamstring allograft. We carried out a prospective cohort study and enrolled 175 patients. 90 of them underwent hamstring tendon autograft ACL reconstruction, and the left (n=85) used hamstring tendon allograft. All of the patients received a minimum of one-year follow-up (mean 2.5 years). The side-to-side difference and the proportion of mononuclear cells in knee joint synovial fluid were measured at six different time points (preoperatively, the 1st week, the 3rd week, the 6th week and the 12th week postoperatively). During the whole early postoperative phase, the side-to-side difference in allograft group demonstrated greater knee laxity than that of autograft group (p<0.001). And the proportion of mononuclear cells sustained at a high level in allograft group at the sixth week and the twelfth week (mean 90.0% and 88.9%, respectively) compared with a normal level in autograft group (mean 45.1% and 65.7%, separately). However, there was no statistical difference between the 2 groups at their final follow-ups in terms of ROM, Lachman test, anterior drawer test, pivot shift test, Lysholm score, bone tunnel enlargement and graft failure rate (p>0.05). This findings suggest that, in the early postoperative phase, ACL reconstruction with hamstring allograft demonstrate a more remarkable knee laxity and immuno-logic response compared with hamstring autograft. However, in a relatively long-term follow-up, both of the grafts achieve similar objective and subjective outcomes.