Effect of Soft Tissue Interposition and Postoperative Suspensory Cortical Button Migration on Functional Outcomes and Ligamentization After Single-Bundle ACL Reconstruction

BACKGROUND: Soft tissue interposition between a suspensory cortical button and the lateral femoral condyle is the most common cause of postoperative suspensory cortical button migration in patients undergoing anterior cruciate ligament reconstruction (ACLR). PURPOSE: To investigate the effects of soft tissue interposition and suspensory cortical button migration after ACLR on functional outcomes and graft ligamentization. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Included were 249 patients who underwent single-bundle ACLR with hamstring tendon autografts. To measure soft tissue imposition, the patients were divided into 2 groups: those in whom the suspensory cortical button was in contact with (group 1) or at least 1 mm away from (group 2) the lateral femoral condyle on 1-day postoperative radiographs. To measure suspensory cortical button migration, the patients in group 2 were further divided into 2 subgroups: those with button migration (group M) and those without migration (group non-M) as observed on 12-month postoperative radiographs. Ligamentization was evaluated according to Howell classification (grades 1-4) on 12-month follow-up magnetic resonance imaging scans. Also recorded were preoperative and 24-month postoperative Lysholm and Tegner scores and 24-month postoperative arthrometer measurements for anterior knee laxity. RESULTS: There was no significant difference between groups 1 and 2 or between groups M and non-M in terms of demographic characteristics or additional intra-articular pathologies detected intraoperatively. Normal anterior laxity (<3 mm) was detected in 83.7% of the patients postoperatively, and all patients showed statistically significant pre- to postoperative improvement on the Tegner (from 4.1 to 4.3) and Lysholm (from 44.0 to 89.2) scores (P < .05 for both). No significant difference in postoperative functional results or graft ligamentization was found between either the soft tissue interposition groups (groups 1 and 2) or the suspensory cortical button migration groups (groups M and non-M). CONCLUSION: Differences between patients in soft tissue interposition and suspensory cortical button migration did not significantly affect postoperative clinical or functional outcomes or graft ligamentization after single-bundle ACLR.