Department of Orthopedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno ward, Osaka, 545-8585, Japan.
Knee Surg Sports Traumatol Arthrosc. 2020 Dec;28(12):3810-3820. doi: 10.1007/s00167-020-05864-2. Epub 2020 Jan 29.
This study aimed to identify factors associated with rotational mismatch after total knee arthroplasty (TKA) using fixed-bearing posterior stabilized prosthesis and to evaluate the impact of the rotational mismatch on clinical outcomes.
This retrospective cohort study included 159 cases that underwent TKA. Whole-leg computed tomography images were obtained 2 weeks after TKA, with three-dimensional measures of alignment. Rotational alignment of the femoral and tibial components and rotational mismatch between components and between the femur and tibia bones were evaluated. The new Knee Society Score (KSS) was obtained at the final outpatient visit, which was defined as the final follow-up timepoint. Predictive factors were identified for rotational mismatch of the lower extremity and poor new KSS.
The mean follow-up period was 42 ± 16 months. Rotational mismatch ≥ 10° between bones was identified in 56 cases (35%), with a mean mismatch angle of 5.0° ± 9.1° of external rotation of the tibia relative to the femur. Rotational mismatch ≥ 10° between components was identified in three cases (2%; mean 0.3° ± 3.6° of internal tibial rotation). A multivariate regression analysis showed that component malrotation was predictive of post-operative rotational mismatch between bones (p < 0.01) and rotational mismatch ≥ 10° associated with poor new KSS (odds ratio 4.22; p < 0.01).
Malrotation of the fixed-bearing posterior stabilized TKA causes a rotational mismatch between the femur and tibia bones. Excessive rotational mismatch between bones greater than 10° is a risk factor for poor postoperative functional outcome. Precise component positioning is essential for improving TKA outcomes.
III.
本研究旨在确定使用固定后稳定型假体进行全膝关节置换术（TKA）后旋转对线不良的相关因素，并评估旋转对线不良对临床结果的影响。
这是一项回顾性队列研究，共纳入 159 例接受 TKA 的患者。TKA 后 2 周，进行下肢全长 CT 扫描，以进行三维对线测量。评估股骨和胫骨假体的旋转对线以及假体之间和股骨与胫骨之间的旋转对线不良。在最终门诊就诊时获得新的膝关节学会评分（KSS），将其定义为最终随访时间点。确定下肢旋转对线不良和新 KSS 评分较差的预测因素。
平均随访时间为 42±16 个月。56 例（35%）存在骨间旋转对线不良≥10°，平均胫骨相对于股骨的外旋旋转对线不良角度为 5.0°±9.1°。3 例（2%）存在组件旋转对线不良≥10°，平均胫骨内旋旋转对线不良角度为 0.3°±3.6°。多变量回归分析显示，组件旋转对线不良与术后骨间旋转对线不良（p<0.01）和旋转对线不良≥10°与新 KSS 评分较差相关（比值比 4.22；p<0.01）有关。
固定后稳定型 TKA 组件的旋转对线不良导致股骨与胫骨之间的旋转对线不良。骨间旋转对线不良超过 10°与术后功能结果较差有关。精确的组件定位对于改善 TKA 结果至关重要。
III 级。
