Watanabe Mutsumi, Kuriyama Shinichi, Nakamura Shinichiro, Tanaka Yoshihisa, Nishitani Kohei, Furu Moritoshi, Ito Hiromu, Matsuda Shuichi
Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.
Knee Surg Sports Traumatol Arthrosc. 2017 Nov;25(11):3459-3466. doi: 10.1007/s00167-017-4570-2. Epub 2017 May 8.
Abnormal knee motion under various conditions has been described after total knee arthroplasty (TKA). However, differences in kinematics and kinetics of knees with varus femoral versus varus tibial alignment have not been evaluated. It was hypothesized that varus femoral and tibial alignments have the same impact on knee motion.
A musculoskeletal computer simulation was used. Femoral and tibial alignment in the coronal plane was each varied from neutral to 5° of varus in 1° increments. Lift-off, defined as an intercomponent distance of >2 mm, and tibiofemoral contact forces were evaluated during gait up to 60° of knee flexion. Knee kinematics and contact stresses were also examined during squat, with up to 130° of knee flexion.
During gait, lift-off occurred readily with more than 3° of varus tibial alignment and slight lateral joint laxity. In contrast, lift-off did not occur with varus femoral or tibial alignment of up to 5° during squat. Peak medial contact forces with varus femoral alignment were approximately twice those observed with varus tibial alignment. The lowest points of the femoral condyles moved internally with varus femoral alignment, contrary to the kinematics with neutral or varus tibial alignment. On the other hand, there was femoral medial sliding and edge loading against the tibia in mid-flexion with varus tibial alignment.
Varus femoral alignment affects the non-physiological rotational movement of the tibiofemoral joint, whereas varus tibial alignment causes medial-lateral instability during mid-flexion. Varus femoral and tibial alignments might lead to post-TKA discomfort and unreliability.
全膝关节置换术（TKA）后已描述了在各种情况下膝关节的异常运动。然而，股骨内翻与胫骨内翻对线的膝关节在运动学和动力学上的差异尚未得到评估。研究假设是股骨内翻和胫骨内翻对线对膝关节运动有相同影响。
采用肌肉骨骼计算机模拟。冠状面的股骨和胫骨对线分别从中立位变化到5°内翻，以1°为增量。将组件间距离>2mm定义为抬起，并在膝关节屈曲至60°的步态过程中评估胫股接触力。在深蹲过程中，膝关节屈曲至130°时也检查膝关节运动学和接触应力。
在步态过程中，胫骨内翻对线超过3°且伴有轻微外侧关节松弛时容易发生抬起。相比之下，在深蹲过程中，股骨或胫骨内翻对线达5°时未发生抬起。股骨内翻对线时的内侧接触力峰值约为胫骨内翻对线时观察到的两倍。股骨髁最低点随股骨内翻对线向内移动，这与中立或胫骨内翻对线时的运动学情况相反。另一方面，胫骨内翻对线时，在屈膝中期股骨会向内侧滑动并边缘加载于胫骨。
股骨内翻对线影响胫股关节的非生理性旋转运动，而胫骨内翻对线在屈膝中期导致内外侧不稳定。股骨内翻和胫骨内翻对线可能导致全膝关节置换术后不适和不可靠。
