Takahashi Tsuneari, Hatayama Kazuhisa, Nishino Masahiro, Kubo Tatsuya, Hai Hironari, Yamada Yuichiro, Suzuki Kosuke, Takeshita Katsushi
Department of Orthopaedics, School of Medicine, Jichi Medical University, Shimotsuke, Japan.
Department of Orthopaedic Surgery, Ishibashi General Hospital, Shimotsuke, Japan.
J Orthop. 2025 Apr 14;63:201-205. doi: 10.1016/j.jor.2025.04.002. eCollection 2025 May.
No study has identified predictors of improvement and decrease in postoperative range of motion (ROM) after medial pivot (MP) total knee arthroplasty (TKA) compared to preoperative ROM. This multicenter study aimed to identify predictors of improved postoperative range of motion (ROM) after MP-TKA.
The study included 107 consecutive patients who underwent MP-TKA for knee osteoarthritis at six different centers. Data on patient age, gender, hip knee angle, and pre- and postoperative ROM in extension and flexion were collected. A 9° improvement or decrease in postoperative knee flexion was considered positive. Patients were divided into three groups according to whether knee flexion improved by more than 9° (group I; 35 patients), changed within the minimal clinically important difference (MCID) (group M; 54 patients), or decreased by more than 9° (group D; 18 patients) one year after surgery.
Significant differences in preoperative ROM for flexion were observed between the groups ( < 0.001). Multivariate and receiver operating characteristic (ROC) curve analyses revealed that preoperative flexion less than 118.0° (area under the curve (AUC): 0.957, 95 % confidence interval (CI): 0.924-0.990) was a significant positive prognostic factor for improved postoperative ROM one year postoperatively (odds ratio (OR): 0.75, 95 % CI: 0.66-0.85, < 0.001) and that preoperative flexion greater than 128.0° (AUC: 0.899, 95 % CI: 0.836-0.961) was a significant positive prognostic factor for decreased postoperative ROM one year postoperatively (OR: 1.14, 95 % CI: 1.07-1.22, < 0.001).
The results showed that a preoperative knee flexion ROM of less than 118° was a significant positive predictor of an improvement in knee flexion ROM of MCID or greater after MP-TKA, and a knee flexion ROM of 128° or greater was a significant positive predictor of a decrease in knee flexion ROM of MCID or greater one year after surgery.
与术前活动范围（ROM）相比，尚无研究确定内侧旋转铰链（MP）全膝关节置换术（TKA）后术后活动范围改善和减小的预测因素。这项多中心研究旨在确定MP-TKA术后活动范围改善的预测因素。
该研究纳入了在六个不同中心因膝关节骨关节炎接受MP-TKA的107例连续患者。收集了患者年龄、性别、髋膝角度以及术前和术后伸直和屈曲时的ROM数据。术后膝关节屈曲改善或减小9°被视为阳性。根据术后一年膝关节屈曲改善是否超过9°（I组；35例患者）、在最小临床重要差异（MCID）范围内变化（M组；54例患者）或减小超过9°（D组；18例患者）将患者分为三组。
各组之间术前屈曲ROM存在显著差异（<0.001）。多变量和受试者工作特征（ROC）曲线分析显示，术前屈曲小于118.0°（曲线下面积（AUC）：0.957，95%置信区间（CI）：0.924 - 0.990）是术后一年术后ROM改善的显著阳性预后因素（优势比（OR）：0.75，95%CI：0.66 - 0.85，<0.001），术前屈曲大于128.0°（AUC：0.899，95%CI：0.836 - 0.961）是术后一年术后ROM减小的显著阳性预后因素（OR：1.14，95%CI：1.07 - 1.22，<0.001）。
结果表明，术前膝关节屈曲ROM小于118°是MP-TKA后膝关节屈曲ROM改善至MCID或更大的显著阳性预测因素，而膝关节屈曲ROM为128°或更大是术后一年膝关节屈曲ROM减小至MCID或更大的显著阳性预测因素。
