Suspensory Versus Interference Tibial Fixation of Hamstring Tendon Autografts in Anterior Cruciate Ligament Reconstruction: Results From the New Zealand ACL Registry

Abstract

Background: The hamstring tendon is frequently used to reconstruct the anterior cruciate ligament (ACL), but there is a lack of consensus on the optimal method of fixation. Registry studies have shown that the type of femoral fixation device can influence the risk of revision ACL reconstruction (ACLR), but it is unclear whether the type of tibial fixation has an effect. In New Zealand, over 95% of hamstring tendon grafts are fixed with an adjustable loop suspensory device on the femoral side, with variable usage between suspensory and interference devices, with or without a sheath, on the tibial side. Purpose: To investigate the association between the type of tibial fixation device and the risk of revision ACLR. Study Design: Cohort Study; Level of evidence, 2. Methods: Prospective data recorded in the New Zealand ACL Registry were analyzed. Only primary ACLRs performed with a hamstring tendon autograft fixed with a suspensory device on the femoral side were included. A Cox regression survival analysis with adjustment for patient factors was performed to analyze the effects of the type of tibial fixation device, the number of graft strands, and graft diameter on the risk of revision. Results: A total of 6145 primary ACLRs performed between 2014 and 2019 were analyzed. A total of 59.6% of hamstring tendon autografts were fixed with a suspensory device on the tibial side (n = 3662), 17.6% with an interference screw with a sheath (n = 1079), and 22.8% with an interference screw without a sheath (n = 1404). When compared with suspensory devices, a higher revision risk was observed when using an interference screw with a sheath (adjusted hazard ratio [HR], 2.05; P = .009) and without a sheath (adjusted HR, 1.81; P = .044). The number of graft strands and a graft diameter of ≥8 mm were associated with the rate of revision on the univariate analysis; however, after adjusting for confounding variables on the multivariate analysis, they did not significantly influence the risk of revision. Conclusion: In this study of hamstring tendon autografts fixed with an adjustable loop suspensory device on the femoral side during primary ACLR, the use of an interference screw, with or without a sheath, on the tibial side resulted in a higher revision rate when compared with a suspensory device.