The loss of knee range of motion (ROM) is not an uncommon complication after anterior cruciate ligament reconstruction (ACLR). However, the risk factors of loss of knee ROM remain debatable. The purpose of this study was to evaluate the incidence and risk factors of loss of knee ROM at 12 months after primary ACLR performed after regaining full knee ROM preoperatively. Consecutive patients who underwent primary ACLR after regaining full ROM between January 2014 and January 2020 were retrospectively reviewed. Patients who received a surgical arthrolysis within 12 months after ACLR or those who had a loss of knee ROM at 12 months postoperatively were defined as the loss of ROM group. Possible risk factors of loss of knee ROM, including patient demographic, preoperative, surgical, and postoperative factors, were assessed. The notch wide index and radiographic parameters of the tibial spines; medial tibial spine height/tibial length (TL), lateral tibial spine height (LTSH)/TL, and tibial spine width (TSW)/TL, were also assessed. A total of 141 patients (141 knees) were included (mean age, 25.8 ± 11.4 years; male/female, 56/85). Of the 141 patients, three received surgical arthrolysis within 12 months, and 23 had a loss of knee ROM at 12 months after ACLR. On comparing patients with and without loss of knee ROM, significant differences were found in the age (p = 0.04), LTSH/TL (p = 0.02), and TSW/TL (p = 0.02). A multivariate regression analysis showed that the age (odds ratio [OR]; 1.05, 95% confidence interval [CI]: 1.01–1.09, p = 0.02), LTSH/TL (OR: 1.44, 95% CI: 1.01–2.1, p = 0.04), and TSW/TL (OR: 0.79, 95% CI: 0.65–0.97, p = 0.02) were identified as significant independent risk predictors of loss of knee ROM. This study showed that the incidence of loss of knee ROM at 12 months after primary ACLR was 18.4% (26/141). An older age, a higher LTSH/TL, and a smaller TSW/TL may be associated with loss of knee ROM at 12 months after ACLR.

中文翻译：

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原发性前十字韧带重建术后膝关节活动度术前恢复后膝关节活动度丧失的危险因素

膝关节活动度（ROM）丧失并不是前十字韧带重建（ACLR）后常见的并发症。然而，膝关节活动度丧失的危险因素仍然存在争议。本研究的目的是评估术前恢复全膝关节活动度后进行初次 ACLR 后 12 个月时膝关节活动度丧失的发生率和危险因素。对 2014 年 1 月至 2020 年 1 月期间恢复完全 ROM 后连续接受初次 ACLR 的患者进行回顾性分析。ACLR术后12个月内接受手术关节松解术的患者或术后12个月膝关节ROM丧失的患者定义为ROM丧失组。评估了膝关节活动度丧失的可能危险因素，包括患者人口统计学、术前、手术和术后因素。胫骨棘切迹宽度指数和放射学参数；还评估了胫骨内侧棘高度/胫骨长度 (TL)、胫骨外侧棘高度 (LTSH)/TL 和胫骨棘宽度 (TSW)/TL。总共纳入 141 名患者（141 个膝盖）（平均年龄，25.8 ± 11.4 岁；男性/女性，56/85）。在 141 名患者中，3 名患者在 12 个月内接受了手术关节松解术，23 名患者在 ACLR 后 12 个月时膝关节活动度丧失。在比较膝关节活动度丧失和未丧失的患者时，发现年龄 (p = 0.04)、LTSH/TL (p = 0.02) 和 TSW/TL (p = 0.02) 存在显着差异。多元回归分析显示，年龄（优势比 [OR]；1.05，95% 置信区间 [CI]：1.01–1.09，p = 0.02）、LTSH/TL（OR：1.44，95% CI：1.01–2.1， p = 0.04）和 TSW/TL（OR：0.79，95% CI：0.65-0.97，p = 0.02）被确定为膝关节活动度丧失的重要独立风险预测因子。这项研究表明，初次 ACLR 术后 12 个月膝关节 ROM 丧失的发生率为 18.4% (26/141)。年龄较大、LTSH/TL 较高和 TSW/TL 较小可能与 ACLR 后 12 个月时膝关节 ROM 丧失相关。