Sports Medicine Service, Beijing Jishuitan Hospital, Beijing, China.
Am J Sports Med. 2020 Mar;48(4):838-846. doi: 10.1177/0363546520902150. Epub 2020 Feb 14.
The lateral meniscus posterior root (LMPR) lesion further decreases dynamic knee stability after anterior cruciate ligament (ACL) injury owing to the loss of the "wedge effect" maintained by the posterior horn of the lateral meniscus. However, the effect of LMPR lesions on the static tibiofemoral relationship in extension after ACL injuries is not determined.
To (1) determine the effect of LMPR lesions on anterior tibial subluxation of the lateral compartment (ATSLC) in extension in patients with ACL injuries and to (2) identify the LMPR-related factors associated with excessive ATSLC in extension.
Cohort study; Level of evidence, 3.
Between January 2015 and December 2017, 405 consecutive patients with diagnosed ACL injuries who underwent primary ACL reconstructions were retrospectively reviewed. Among them, 45 patients with combined ACL injuries and LMPR lesions (ACL+LMPR group) and 51 patients with isolated ACL injuries (ACL group) were identified. Values of ATSLC in extension were measured on preoperative supine magnetic resonance imaging and classified into high grade (≥6 mm) and low grade (<6 mm). The mean ATSLC in extension and the proportion of patients with high-grade ATSLC in extension were compared between the groups by univariate analysis. In the ACL+LMPR group, predictors of high-grade ATSLC in extension-including age, sex, body mass index, affected side, cause of injury, period from injury (<12 or ≥12 weeks), LMPR lesion pattern (radial tear or root avulsion), and meniscofemoral ligament integrity (intact or impaired)-were assessed by univariate analysis and multivariate logistic regression analysis.
The mean ATSLC in extension in the ACL+LMPR group was significantly greater than that in the ACL group (5.6 mm vs 3.1 mm; = .001). The proportion of patients with high-grade ATSLC in extension in the ACL+LMPR group was also significantly larger than that in the ACL group (44.4% vs 15.7%; = .002). In addition, the root avulsion (instead of radial tear) (odds ratio, 28.750; 95% CI, 2.344-352.549; = .009) and the period from injury ≥12 weeks (odds ratio, 17.095; 95% CI, 1.207-242.101; = .036) were determined to be the 2 independent predictors of high-grade ATSLC in extension. However, age, sex, body mass index, affected side, cause of injury, and meniscofemoral ligament integrity were not.
After ACL injuries, concomitant LMPR lesion further increased ATSLC in extension. Chronic LMPR avulsion was associated with high-grade ATSLC in extension.
前交叉韧带（ACL）损伤后，外侧半月板后根（LMPR）病变进一步降低了膝关节的动态稳定性，这是由于外侧半月板后角维持的“楔形效应”丧失。然而，LMPR 病变对 ACL 损伤后伸展时胫骨股骨静态关系的影响尚未确定。
（1）确定 LMPR 病变对 ACL 损伤患者伸展时外侧间室胫骨前半脱位（ATSLC）的影响，（2）确定与伸展时过度 ATSLC 相关的 LMPR 相关因素。
队列研究；证据水平，3 级。
2015 年 1 月至 2017 年 12 月，回顾性分析了 405 例诊断为 ACL 损伤且接受初次 ACL 重建的连续患者。其中，45 例 ACL 合并 LMPR 损伤患者（ACL+LMPR 组）和 51 例单纯 ACL 损伤患者（ACL 组）被识别。通过术前仰卧位磁共振成像测量伸展时的 ATSLC 值，并分为高等级（≥6mm）和低等级（<6mm）。通过单因素分析比较两组伸展时 ATSLC 的平均值和伸展时高等级 ATSLC 的患者比例。在 ACL+LMPR 组中，通过单因素分析和多因素逻辑回归分析评估伸展时高等级 ATSLC 的预测因素，包括年龄、性别、体重指数、患侧、损伤原因、受伤时间（<12 周或≥12 周）、LMPR 病变模式（放射状撕裂或根撕脱）和半月板股骨韧带完整性（完整或受损）。
ACL+LMPR 组伸展时的平均 ATSLC 明显大于 ACL 组（5.6mm vs 3.1mm； =.001）。伸展时高等级 ATSLC 的患者比例在 ACL+LMPR 组也明显大于 ACL 组（44.4% vs 15.7%； =.002）。此外，根撕脱（而非放射状撕裂）（比值比，28.750；95%置信区间，2.344-352.549； =.009）和受伤时间≥12 周（比值比，17.095；95%置信区间，1.207-242.101； =.036）被确定为伸展时高等级 ATSLC 的 2 个独立预测因素。然而，年龄、性别、体重指数、患侧、损伤原因和半月板股骨韧带完整性不是。
ACL 损伤后，合并 LMPR 病变进一步增加了伸展时的 ATSLC。慢性 LMPR 撕脱与伸展时高等级 ATSLC 有关。
