Comparison of Tibial Cortical Button Fixation and Bioabsorbable Interference Screw Plus U-Staple Fixation in Anterior Cruciate Ligament Reconstruction: A Retrospective Cohort Study

Background and Objectives: This study aimed to compare the clinical, functional, and graft-related outcomes of two tibial fixation constructs used in primary hamstring autograft anterior cruciate ligament reconstruction (ACLR): tibial cortical button fixation and bioabsorbable interference screw fixation reinforced with a U-shaped staple. Materials and Methods: This retrospective two-center comparative cohort study included 58 patients with isolated anterior cruciate ligament injuries who underwent primary ACLR and had a minimum postoperative follow-up of 12 months. Patients were classified into the cortical button group (n = 26) or the U-staple group (n = 32) according to the initial graft diameter, which strictly dictated the tibial fixation construct documented in the operative report. Both the semitendinosus and gracilis tendons were used in each group. A shorter quadrupled graft construct was prepared in the cortical button group, whereas a longer doubled graft construct was used in the U-staple group. Donor-site pain measured using the visual analog scale (VAS), graft diameter, International Knee Documentation Committee (IKDC) score, Lysholm score, knee range of motion (ROM), Lachman and pivot-shift findings, and graft failure were compared between the groups. Graft failure was defined as magnetic resonance imaging (MRI) evidence of graft discontinuity or insufficiency accompanied by grade 2–3 Lachman laxity or a positive pivot-shift test. Numerical variables were analyzed using the Mann–Whitney U test, whereas categorical variables were compared using the Pearson chi-square or Fisher’s exact test, as appropriate. Results: Donor-site pain was significantly higher in the cortical button group than in the U-staple group [median VAS score: 2.5 (2.0–4.0) vs. 2.0 (0–2.0), respectively; p = 0.007]. Graft diameter was also significantly greater in the cortical button group [10.0 mm (10.0–10.0) vs. 9.0 mm (8.0–9.0); p < 0.001]. In contrast, IKDC scores were significantly higher in the U-staple group [71.0 (51.5–78.0) vs. 60.0 (55.0–62.8); p = 0.017]. No significant differences were observed in Lysholm scores (p = 0.701), knee ROM (p = 0.508), positive pivot-shift findings (11.5% vs. 6.3%; p = 0.648), clinically relevant Lachman laxity (30.8% vs. 18.8%; p = 0.287), or graft failure rates (11.5% vs. 18.8%; p = 0.495). Conclusions: No significant between-group differences were observed in Lysholm scores, knee ROM, clinical stability, or graft failure rates after hamstring autograft ACLR. The U-staple group demonstrated lower donor-site pain and higher IKDC scores, whereas the cortical button group had larger graft diameters, likely reflecting the shorter quadrupled graft configuration. Overall, neither tibial fixation construct showed a consistent advantage across all clinical outcomes.