Tsushima Takahiro, Sasaki Eiji, Sasaki Shizuka, Oishi Kazuki, Kimura Yuka, Sakamoto Yukiko, Tsuda Eiichi, Ishibashi Yasuyuki
Department of Orthopedic Surgery, Hirosaki University, Graduate School of Medicine, Hirosaki, Japan.
Department of Orthopedic Surgery, Hirosaki University, Graduate School of Medicine, Hirosaki, Japan.
J ISAKOS. 2024 Dec;9(6):100357. doi: 10.1016/j.jisako.2024.100357. Epub 2024 Oct 30.
Physiologic knee kinematics is crucial for successful total knee arthroplasty (TKA) but are often not replicated. Using a medial stabilizing technique (MST) minimizes bone resection but results in lateral laxity. This study aimed to investigate the effects of lateral laxity on knee kinematics and symptoms after TKA.
Mobile-bearing cruciate-retaining MST-TKA was performed on 40 knees using a navigation system. In the kinematic analysis, the anteroposterior (AP) translations of the medial femoral condyle (MFC) and lateral femoral condyle (LFC), femoral rotation angles, and medial and lateral component gaps were recorded every 0.1 s. These data were extracted from the software from 0° to 120° flexion in 10° increments. Kinematics was classified as the medial center of rotation (MCR) or non-MCR between 0° to 90° of flexion. Lateral laxity was calculated by subtracting the medial component gap from the lateral component gap. The final follow-up Knee Injury and Osteoarthritis Outcome Scores (KOOS) were evaluated. The relationships between the pre- and post-operative kinematics and between postoperative lateral laxity and kinematics were assessed using Spearman's correlation coefficients. Finally, the correlation between postoperative lateral laxity and KOOS symptoms was evaluated using linear regression analysis.
Preoperative kinematics, including AP translation of the MFC and LFC and femoral rotation, correlated with postoperative kinematics (all P < 0.001). Additionally, postoperative lateral laxity correlated with postoperative AP translation of the MFC, LFC, and femoral rotation (all P < 0.001). Furthermore, the receiver operating characteristic analysis indicated a cutoff value of 0.9 mm on postoperative lateral laxity at 90° flexion for postoperative MCR (P < 0.001). Postoperative lateral laxity at 90° flexion was significantly correlated with KOOS symptoms (β = 0.465, P = 0.025).
Preoperative kinematics and postoperative lateral laxity correlated with postoperative kinematics after MST-TKA. Postoperative lateral laxity greater than 0.9 mm at 90° flexion was associated with physiological kinematic motion, leading to fewer knee symptoms in the PROMs. The key to successful TKA was considered to be keeping the asymmetric gap balance with physiological lateral laxity, rather than the conventional symmetrical gap balance.
Retrospective study.
生理性膝关节运动学对全膝关节置换术（TKA）的成功至关重要，但往往难以复制。采用内侧稳定技术（MST）可减少骨切除，但会导致外侧松弛。本研究旨在探讨TKA术后外侧松弛对膝关节运动学和症状的影响。
使用导航系统对40例膝关节进行活动平台保留交叉韧带的MST-TKA手术。在运动学分析中，每0.1秒记录一次股骨内侧髁（MFC）和股骨外侧髁（LFC）的前后（AP）平移、股骨旋转角度以及内侧和外侧组件间隙。这些数据从软件中以10°增量提取，范围为0°至120°屈曲。运动学在0°至90°屈曲之间被分类为内侧旋转中心（MCR）或非MCR。外侧松弛通过从外侧组件间隙中减去内侧组件间隙来计算。评估末次随访时的膝关节损伤和骨关节炎疗效评分（KOOS）。使用Spearman相关系数评估术前和术后运动学之间以及术后外侧松弛与运动学之间的关系。最后，使用线性回归分析评估术后外侧松弛与KOOS症状之间的相关性。
术前运动学，包括MFC和LFC的AP平移以及股骨旋转，与术后运动学相关（所有P<0.001）。此外，术后外侧松弛与术后MFC、LFC的AP平移以及股骨旋转相关（所有P<0.001）。此外，受试者工作特征分析表明，90°屈曲时术后外侧松弛的临界值为0.9mm时为术后MCR（P<0.001）。90°屈曲时的术后外侧松弛与KOOS症状显著相关（β=0.465，P=0.025）。
MST-TKA术后，术前运动学和术后外侧松弛与术后运动学相关。90°屈曲时术后外侧松弛大于0.9mm与生理性运动学运动相关，导致患者报告结局测量（PROMs）中的膝关节症状较少。成功进行TKA的关键被认为是保持具有生理性外侧松弛的不对称间隙平衡，而不是传统的对称间隙平衡。
III级：回顾性研究。
