胫骨后倾角双侧对称性差限制了健侧肢体作为前交叉韧带重建手术规划可靠参考的应用
简介
该研究回顾性分析了2016-2023年间ACL损伤患者的术前膝关节侧位X线片，包括双侧ACL损伤（Bi-ACL，59例）和单侧ACL损伤（Uni-ACL，189例，对侧膝至少5年随访健康），测量双侧内侧和外侧胫骨后倾角（MPTS、LPTS），评估其对称性。关键发现：Bland-Altman分析显示95%一致性界限跨度达17°-22°，远超临床决策阈值；在≥1…
英文摘要
PURPOSE: To assess the symmetry of posterior tibial slope (PTS) between knees in patients with anterior cruciate ligament (ACL) injury to evaluate whether the contralateral limb can serve as a reliable reference for risk stratification and surgical planning. METHODS: A retrospective comparative study was conducted. Preoperative lateral knee radiographs from patients with ACL injury treated between 2016 and 2023 were analysed. Two cohorts were studied: bilateral ACL injuries (Bi-ACL; n = 59) and unilateral ACL injury (Uni-ACL; n = 189) with radiographically healthy contralateral knee at minimum 5-year follow-up. Medial posterior tibial slope (MPTS) and lateral posterior tibial slope (LPTS) were measured bilaterally using a standardized protocol. Side-to-side symmetry was assessed using Bland-Altman analysis with 95% limits of agreement, Cohen's κ for threshold concordance, and proportion of patients exceeding the minimal detectable change (MDC95 ≈ 5°). RESULTS: Bland-Altman 95% limits of agreement spanned 17°-22° across all comparisons, far exceeding clinically relevant decision thresholds. Concordance at the ≥12° threshold was only 19% in Bi-ACL (4/21) and 2% in Uni-ACL (1/46). Cohen's κ indicated poor agreement (0.1 for Bi-ACL; -0.1 for Uni-ACL, indicating worse than chance). When applying rigorous MDC95 thresholds that account for measurement error, 29%-36% of patients demonstrated inter-knee asymmetry definitively exceeding measurement noise. In Uni-ACL patients, the injured knee exhibited significantly steeper slopes than the healthy contralateral knee (MPTS + 1.8°, p < 0.001; LPTS + 1.1°, p = 0.001). CONCLUSIONS: PTS showed limited side-to-side symmetry in ACL-injured patients, with poor concordance at the ≥12° threshold and ~33% demonstrating inter-knee asymmetry beyond expected measurement error. The contralateral knee may therefore be an unreliable surrogate for estimating index-knee PTS, and PTS should be measured independently for each knee on standardized radiographs when used for clinical decision-making. LEVEL OF EVIDENCE: Level IV, retrospective case series.