Effect of Posterolateral Bundle Graft Fixation Angles on Clinical Outcomes in Double-Bundle Anterior Cruciate Ligament Reconstruction

Abstract

Background: In double-bundle (DB) anterior cruciate ligament (ACL) reconstruction, no consensus exists on an optimal setting for the posterolateral bundle (PLB) graft fixation angles. Hypothesis: Different PLB fixation angles would affect clinical outcomes in DB ACL reconstruction. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: This study prospectively included 90 patients who underwent primary DB ACL reconstruction with an autologous semitendinosus tendon. The PLB fixation angles were randomly set as follows: 0° of flexion (P0; n = 30), 20° (P20; n = 30), and 45° (P45; n = 30). In all groups, the anteromedial bundle was fixed at 20° of flexion. The following evaluation methods were used at the preoperative period and at 3, 6, and 9 months and 1 and 2 years after the surgery: clinical examination, KT-1000 arthrometer measurement, muscle strength, Tegner score, Lysholm score, and subjective rating scale regarding patient satisfaction and sports performance levels. Graft retear, contralateral ACL tear, and additional meniscus surgery were also recorded. Results: Seventy-five patients (P0, n = 25; P20, n = 26; P45, n = 24) who were followed for 2 years were evaluated. Preoperatively, there were no differences among the groups. Postoperatively, pivot-shift test results in the P0 and P20 groups were better than those in the P45 group (P0, n = 23 graded negative and 2 graded 1+; P20, n = 23 and 2; P45, n = 15 and 7, respectively; P0 vs P45: P = .038 and P20 vs P45: P = .038). Average KT-1000 arthrometer laxity measurements were better in the P20 group than in the P45 group (P0, 0.4 mm; P20, 0.3 mm; P45, 1.3 mm; P20 vs P45: P = .048), and there were more patients with graft failure (KT-1000 measurement, ≥4 mm) in the P45 group (n = 3) than the P0 and P20 groups (each, n = 0). There were no significant differences in range of motion, other laxity tests, muscle strength, Tegner score, Lysholm score, subjective rating scale, or additional surgery. Conclusion: In DB ACL reconstruction, when the anteromedial bundle was fixed at 20° of flexion, fixation of the PLB at 45° was worse than fixation at 0° and 20° with respect to anterior and rotational stability during the 2-year follow-up. KT-1000 arthrometer measurements and pivot-shift test results were significantly worse, and there were more patients with graft failure in the P45 group. There were no differences among groups in other findings.