Effect of tibial remnant preservation on clinical, radiological and surgical outcomes in anterior cruciate ligament reconstruction: a retrospective single-center comparative study.

backgroundPreserving the tibial remnant of a torn anterior cruciate ligament (ACL) during reconstruction is thought to enhance graft revascularisation, proprioception, and tunnel healing. However, evidence of clinical benefit remains inconsistent, and any effect size may be small. We retrospectively compared outcomes of ACL reconstruction with versus without tibial remnant preservation, explicitly accounting for potential confounders.

methodsBetween January 2018 and June 2023, 211 consecutive patients (mean age ~ 29 years) underwent primary single-bundle hamstring ACL reconstruction at our center. Group 1 (n = 79) had tibial remnant preservation determined intra-operatively based on remnant quality, and Group 2 (n = 132) underwent conventional reconstruction with complete remnant excision. Inclusion required ≥ 24 months of follow-up (mean follow-up 46 ± 17 months, range 24–72). Baseline age and sex distributions were comparable, but the injury-to-surgery interval was markedly shorter in Group 1 (4.6 ± 1.2 months) than in Group 2 (8.4 ± 2.2 months). We compared demographic, surgical, and clinical outcomes. Primary outcomes included knee stability (Lachman and pivot-shift tests), functional scores (Lysholm knee score), radiographic tibial/femoral tunnel widening, graft failure requiring revision, and graft survival. Continuous variables were analyzed with independent t-tests or Mann–Whitney U tests and are reported as mean differences with 95% confidence intervals (CIs). Categorical variables were compared with chi-square or Fisher’s exact tests and reported as risk differences with 95% CIs.

resultsAge (28.9 ± 6.4 vs. 29.3 ± 6.1 years) and follow-up duration (46.2 ± 16.8 vs. 45.3 ± 17.4 months) were similar between groups. The time from injury to surgery differed by − 3.8 months (95% CI − 4.3 to − 3.3), reflecting earlier surgery in the remnant-preserved group. Postoperative Lysholm scores were high in both groups and did not differ (mean difference = 1.4 points, 95% CI − 0.18 to 2.98; p = 0.083). At final follow-up (mean ~ 46 months), negative Lachman tests were more frequent in Group 1 (89.9%) than in Group 2 (74.2%), an absolute difference of 15.6% points (95% CI 5.6 to 25.6; p = 0.007). Similarly, the pivot-shift test was negative in 94.9% of Group 1 versus 83.8% of Group 2 (difference = 10.8% points, 95% CI 3.0 to 18.7; p = 0.026). Mean tibial tunnel widening was 0.30 mm less in Group 1 (difference = − 0.30 mm, 95% CI − 0.42 to − 0.18; p < 0.001), and the risk of > 2 mm tibial widening was 5.1% in Group 1 versus 15.2% in Group 2 (difference = − 10.1% points, 95% CI − 17.9 to − 2.3; p = 0.026). Revision ACL surgery was required in 2 patients (2.5%) in Group 1 and 14 patients (10.6%) in Group 2 (risk difference = − 8.1% points, 95% CI − 14.4 to − 1.8; p = 0.034). At final follow-up, Kaplan–Meier analysis showed higher revision-free survival in Group 1 than Group 2 (97.4% vs. 89.4%; log-rank p = 0.031). In a Cox regression model, tibial remnant preservation had a hazard ratio of 0.30 (95% CI 0.06–1.47), suggesting a lower revision risk; however, the confidence interval included 1, indicating this trend did not reach statistical significance.

conclusionsPreservation of a well-quality tibial ACL remnant was associated with better objective knee stability and a lower early revision rate compared with complete remnant excision, while subjective functional scores were similar. Because the study was retrospective and the remnant-preserved group underwent earlier surgery, these findings should be interpreted with caution. Remnant preservation may be a useful adjunct when feasible, but prospective randomized studies controlling for confounders are required to determine causality.