Remnant preservation and stump suturing in anterior cruciate ligament reconstruction reduce tibial tunnel widening without compromising tunnel placement: A computed tomography‐based randomised controlled trial

Purpose Tunnel widening remains a concern following anterior cruciate ligament reconstruction because it may adversely affect graft incorporation and complicate revision surgery. Remnant preservation has been proposed as a strategy to reduce tunnel widening, but its effect on postoperative tunnel remodelling remains uncertain. This study aimed to determine whether remnant preservation with tibial stump suturing reduces tunnel widening without compromising tunnel placement accuracy. Methods In this prospective randomised controlled trial, 179 patients undergoing primary anterior cruciate ligament (ACL) reconstruction were randomised to remnant‐preserving reconstruction with tibial stump suturing ( n = 88) or conventional stump resection ( n = 91). Standardised three‐dimensional computed tomography was performed at 2 weeks and 1 year postoperatively. Tibial and femoral tunnel widening were calculated as the percentage change in tunnel diameter between scans, and tunnel placement accuracy was assessed using the computed tomography‐based quadrant method. The incidence of clinically significant tunnel widening (>20%) was also compared. Results Baseline tunnel diameters were comparable between groups. At 1‐year follow‐up, remnant‐preserving ACL reconstruction resulted in significantly less tibial tunnel widening than stump resection (14.58 ± 4.49% vs. 19.74 ± 4.36%, p < 0.001), with a lower incidence of clinically significant widening (>20%) (11.4% vs. 25.3%; relative risk, 0.45; p = 0.016). Femoral tunnel widening was similar between groups (18.23 ± 2.92% vs. 18.35 ± 2.59%, p = 0.766). No clinically relevant differences in tunnel placement were observed between groups. Conclusion Remnant‐preserving ACL reconstruction with tibial stump suturing selectively reduces tibial tunnel widening at 12 months without compromising anatomic tunnel placement accuracy. These findings support the use of remnant preservation when preservation of tibial tunnel integrity is a surgical consideration. Level of Evidence Level I. Trial Registration ClinicalTrials.gov , NCT07236593; registration date: November 15, 2025 (retrospectively registered).