Adjustable Versus Fixed Loop Devices and Revision Risk After Primary ACL Reconstruction With Hamstring Autograft

Background: Adjustable loop devices (ALDs) have become popular for graft fixation in anterior cruciate ligament reconstruction (ACLR) because of their combination of convenience and biomechanical strength. Their design introduces a new mechanism of failure (loop lengthening), which is not present in fixed loop devices (FLDs). Purpose: To identify the association between use of ALD and risk of revision and reoperation after hamstring tendon autograft ACLR compared with other femoral fixation devices. Study Design: Cohort study; Level of evidence, 3. Methods: Data from Kaiser Permanente’s ACLR registry were used to conduct a cohort study. Patients who underwent primary isolated ACLR using a hamstring tendon autograft were identified (2009-2022). The cohort was restricted to ACLR using an interference screw on the tibial side. A femoral fixation device, including an ALD, FLD, and interference screw, was used for treatment. Cox proportional hazard regression was used to evaluate the risk of aseptic revision, ipsilateral aseptic reoperation, and contralateral knee operation with confounder adjustment. Models compared ALDs and FLDs to the interference screw, as well as ALDs versus FLDs. Results: The final study sample comprised 6910 ACLRs, 3900 ALDs, 1435 FLDs, and 1575 interference screws. Crude revision incidence at the 11-year follow-up was 5.5%, 6.4%, and 4.9% for ALD, FLD, and interference screw, respectively. In adjusted analysis, no differences in revision risk were observed when comparing ALD (hazard ratio [HR], 1.11 [95% CI, 0.82-1.51]) and FLD (HR, 1.16 [95% CI, 0.81-1.67]) to interference screw; or when comparing ALD with FLD (HR, 0.96 [95% CI, 0.69-1.32]). No differences in ipsilateral reoperation risk were observed when comparing ALD and FLD to the interference screw. However, a lower risk of ipsilateral reoperation was observed when comparing ALD with FLD (HR, 0.75 [95% CI, 0.58-0.97]; P = .027). A lower risk of contralateral operation was observed for ALD (HR, 0.51 [95% CI, 0.38-0.68]; P < .001) and FLD (HR, 0.70 [95% CI, 0.50-0.98]; P = .035) compared with the interference screw; no difference was observed for ALD versus FLD. Conclusion: This registry-based cohort study found no difference in the risk of revision when ALD and FLD were compared with interference screw, or when ALD was directly compared with FLD, for femoral fixation of hamstring tendon autografts. There was a higher risk of ipsilateral reoperation with FLD compared with ALD. Surgeons can use these data when choosing fixation for hamstring tendon autograft ACLR.