Evaluating the Impact of Adjustable- and Fixed-Loop Femoral Endobuttons on Intraoperative Surgeon Satisfaction and Postoperative Patient Functional Outcomes in Anterior Cruciate Ligament (ACL) Reconstruction

Introduction: This study aims to evaluate the effects of adjustable- and fixed-loop femoral endobuttons on intraoperative surgeon satisfaction and postoperative patient functional outcomes in anterior cruciate ligament (ACL) reconstruction. The use of cortical suspensory devices, either fixed-loop or adjustable-loop, is common in ACL reconstruction surgeries for femoral tunnel fixation. Fixed-loop devices, although effective, often require additional tunnel drilling, potentially leading to tunnel widening. Adjustable-loop devices were introduced to mitigate this issue. However, there are concerns regarding the mechanical performance of adjustable loops, particularly under cyclical loading, which could affect long-term graft stability.

Materials and methods: This retrospective comparative study compares functional outcomes and intraoperative assessments of 140 patients who underwent ACL reconstruction between 2017 and 2021 with fixed-loop and adjustable-loop devices for the femoral side. Patients were evaluated at six weeks, six months, one year, and two years postoperatively using the Lysholm score, International Knee Document Committee score, Tegner activity scores, and knee stability tests, including Lachman and anterior drawer tests. Additionally, the study captured surgeon satisfaction intraoperatively and compared it with the final functional outcome.

Results: Both groups demonstrated significant improvements in knee stability, range of motion (ROM), and functional scores over time. At six weeks, the anterior drawer test showed 61 stable knees out of 70 in the adjustable-loop group and 57 of 70 in the fixed-loop group, with stability maintained in 56 and 49 knees, respectively, at the final follow-up. The mean extension at two years was 0.5° ± 3.8° in the fixed-loop group and -1.3° ± 3.2° in the adjustable-loop group (p = 0.02). Although the adjustable-loop group showed trends toward better early knee stability and extension, these differences were not statistically significant at two years (p > 0.05).

Conclusion: Surgeons' intraoperative satisfaction with graft firmness was higher in the adjustable-loop group. However, this did not correlate with long-term functional outcomes, as both groups had comparable scores at the final follow-up. Further research with larger sample sizes and extended follow-up periods is needed to confirm these findings. The limitations of this study include its retrospective design, the potential for selection bias, and the subjective nature of intraoperative assessments.