Anterior Laxity, Slippage, and Recovery of Function in the First Year After Tibialis Allograft Anterior Cruciate Ligament Reconstruction

Abstract

Background: The increase in anterior laxity and slippage is greater with metal interference screw fixation of a hamstring anterior cruciate ligament (ACL) graft than a bone-patellar tendon-bone graft. Hypothesis: When slippage-resistant fixation is used with a soft tissue graft, early recovery of function does not result in a clinically important increase in anterior laxity and slippage Study Design: Case series; Level of evidence, 4. Methods: Nineteen subjects were treated with a single-tunnel, single-looped, tibialis allograft with slippage-resistant, cortical fixation. An examiner, different from the treating surgeon, used stereophotogrammetric analysis to compute the increase in anterior laxity at a 150 N anterior force and slippage between the day of surgery and each monthly follow-up interval, and determined recovery of function and motion. Results: Anterior laxity did not increase between the day of surgery and 1 year (P = .23). Total slippage plateaued after 1 month, but increased 1.5 mm between the day of surgery and 1 month (P < .05). Extension and flexion plateaued after 2 months (P < .0001 and P < .02, respectively); activity level (Tegner score) plateaued after 3 months (P < .05), function (Lysholm score) plateaued after 4 months (P < .002), and subjective satisfaction (International Knee Documentation Committee score) plateaued after 6 months (P < .02). Conclusion: Early recovery of function after ACL reconstruction with a soft tissue allograft did not result in a clinically important increase in anterior laxity and slippage at 1 year. We believe the avoidance of an increase in anterior laxity was related to the use of a transtibial technique designed to place the femoral and tibial tunnels without roof and posterior cruciate ligament impingement, the use of cortical fixation devices designed to resist slippage, the use of an aseptically harvested fresh-frozen tibialis allograft that was not irradiated or chemically processed, and the use of a self-administered rehabilitation program designed to encourage an early return of motion and function.