This study aimed to evaluate the relationship between the femoral and tibial component positions and postoperative knee range of motion after posterior-stabilized total knee arthroplasty (TKA). Forty-four patients (48 knees in total: 9 men, 9 knees; 35 women, 39 knees) who underwent posterior-stabilized TKA using a navigation system were included. The femoral and tibial component positions were measured from the preoperative and postoperative computed tomography data with three-dimensional evaluation software. We investigated the relationship between the knee range of motion, including extension restriction and maximum flexion angles at 2 years postoperatively, and the femoral and tibial component positions. Patients with knee extension restriction of 10° or more at 2 years postoperatively showed greater posterior flexion position of the tibial component than those with knee extension restriction less than 10° (6.2° and 3.9°, respectively, p=0.018). The postoperative knee flexion angle was positively associated with the internal rotational position of the femoral component (p=0.032, 95% confidence interval: 0.105–2.178). Patients with a knee flexion angle more than 120° at 2 years postoperatively had greater internal rotational position of the femoral component than those with 120° or less (5.2° and 1.5°, respectively, p=0.002). In conclusions, after posterior-stabilized TKA, the postoperative knee extension restriction angle was associated with the posterior flexion position of the tibial component, and the knee flexion angle was positively related to the internal rotational position of the femoral component.

本研究旨在评估后稳定全膝关节置换术（TKA）后股骨和胫骨假体位置与术后膝关节活动范围之间的关系。纳入使用导航系统进行后稳定 TKA 的 44 名患者（总共 48 膝：9 名男性，9 名膝；35 名女性，39 名膝）。使用三维评估软件根据术前和术后计算机断层扫描数据测量股骨和胫骨假体位置。我们研究了膝关节活动范围（包括术后 2 年的伸展限制和最大屈曲角度）与股骨和胫骨假体位置之间的关系。术后 2 年膝关节伸展受限为 10° 或以上的患者比膝关节伸展受限小于 10° 的患者表现出更大的胫骨后屈位置（分别为 6.2° 和 3.9°，p = 0.018 ）。术后膝关节屈曲角度与股骨假体的内旋位置呈正相关（p =0.032，95%置信区间：0.105-2.178）。术后2年膝关节屈曲角度超过120°的患者股骨假体的内旋位置高于120°或以下的患者（分别为5.2°和1.5°，p = 0.002 ）。结论：后稳定TKA术后，术后膝关节伸直受限角度与胫骨假体后屈位置相关，膝关节屈曲角度与股骨假体内旋位置正相关。