Summary

Patients who underwent ACLR with allograft compared to autograft had a 2-times higher risk of undergoing a TKA during follow-up, and additional risk factors for TKA after ACLR included patient age, female gender, concomitant chondral injury, and ipsilateral reoperation or contralateral surgery during follow-up.

Abstract

Background

Adjustable Loop Devices (ALD) have become popular for graft fixation in anterior cruciate ligament reconstruction (ACLR) due to 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 (FLD). Biomechanical studies have shown that ALD are susceptible to loop lengthening under cyclic loading which can be improved through knot tying or re-tensioning. We sought to identify the association between use of ALDs and risk of revision and reoperation after primary ACLR with hamstring autograft compared to other femoral fixation devices.

Methods

Data from a US healthcare system’s ACLR registry was used to conduct a cohort study. Patients who underwent primary isolated ACLR using a hamstring autograft were identified (2009-2022). The study cohort restricted to ACLR using an interference screw on the tibial side. The treatment of interest was femoral fixation device, including ALD, FLD, and interference screw. Outcomes of interest included aseptic revision and ipsilateral aseptic reoperation during follow-up. Cox proportional hazard regression was used to evaluate the association between femoral fixation device and outcomes with adjustment for age, body mass index, gender, race/ethnicity, American Society of Anesthesiologist’s classification, activity at the time of injury, meniscal or chondral injuries, and tibial tunnel drilling technique. Models compared ALD and FLD fixation to interference screw, as well as ALD vs FLD fixation.

Results

The final study sample comprised 6910 ACLR, 3900 using ALD, 1435 using FLD, and 1575 using interference screw. Procedures were performed by 202 surgeons at 54 hospitals. More patients were male (59.3%) and soccer as the most frequent activity at the time of injury (24.4%). Median follow-up for the cohort was 5.5 years (interquartile range=2.6-8.8).

Crude cumulative incidence of revision at 11-years 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 (HR=1.11, 95% CI=0.82-1.51, p=0.493) and FLD (HR=1.16, 95% CI=0.81-1.67, p=0.415) to interference screw. Similarly, no difference in revision risk was observed when directly comparing ALD to FLD (HR=0.96, 95% CI=0.69-1.32, p=0.788).

At 11-years follow-up, crude cumulative incidence of ipsilateral reoperation was 7.7% for ALD, 10.5% for FLD, and 9.0% for interference screw. In adjusted analysis, no differences in ipsilateral reoperation risk were observed when comparing ALD (HR=0.81, 95% CI=0.58-1.14, p=0.224) and FLD (HR=1.09, 95% CI=0.78-1.52, p=0.635) to interference screw. However, a lower risk of ipsilateral reoperation was observed when directly comparing ALD to FLD (HR=0.75, 95% CI=0.58-0.97, p=0.027).

Conclusions

This registry-based cohort study found no difference in aseptic revision ACLR between ALD, FLD and interference screw after primary ACLR with hamstring autograft. However, the risk of ipsilateral reoperation was higher with FLD compared to ALD. Further research is needed to evaluate differences in return to play between fixation devices.