Kang Kyoung-Tak, Kwon Sae Kwang, Son Juhyun, Kwon Oh-Ryong, Lee Jun-Sang, Koh Yong-Gon
Department of Mechanical Engineering, Yonsei University, Seodaemun-gu, Seoul, Republic of Korea.
Joint Reconstruction Center, Department of Orthopaedic Surgery, Yonsei Sarang Hospital, Seoul, Republic of Korea.
Knee. 2018 Oct;25(5):903-914. doi: 10.1016/j.knee.2018.06.011. Epub 2018 Jul 3.
Postoperative changes of the femoral posterior condylar offset (PCO) and posterior tibial slope (PTS) affect the biomechanics of the knee joint after fixed-bearing total knee arthroplasty (TKA). However, the biomechanics of mobile-bearing is not well known. Therefore, the aim of this study was to investigate whether alterations to the PCO and PTS affect the biomechanics for mobile-bearing TKA.
We used a computational model for a knee joint that was validated using in vivo experiment data to evaluate the effects of the PCO and PTS on the tibiofemoral (TF) joint kinematics, patellofemoral (PF) contact stress, collateral ligament force and quadriceps force, for mobile-bearing TKA. The computational model was developed using ±1-, ±2- and ±3-mm PCO models in the posterior direction and -3°, 0°, +3°, and +6° PTS models based on each of the PCO models.
The maximum PF contact stress, collateral ligament force and quadriceps force decreased as the PTS increased. In addition, the maximum PF contact stress and quadriceps force decreased, and the collateral ligament force increased as PCO translated in the posterior direction. This trend is consistent with that observed in any PCO and PTS.
Our findings show the various effects of postoperative alterations in the PCO and PTS on the biomechanical results of mobile-bearing TKA. Based on the computational simulation, we suggest that orthopaedic surgeons intraoperatively conserve the patient's own anatomical PCO and PTS in mobile-bearing TKA.
在固定平台全膝关节置换术（TKA）后，股骨后髁偏移（PCO）和胫骨后倾（PTS）的术后变化会影响膝关节的生物力学。然而，活动平台的生物力学尚不清楚。因此，本研究的目的是调查PCO和PTS的改变是否会影响活动平台TKA的生物力学。
我们使用了一个膝关节计算模型，该模型通过体内实验数据进行了验证，以评估PCO和PTS对活动平台TKA的胫股（TF）关节运动学、髌股（PF）接触应力、侧副韧带力和股四头肌力量的影响。该计算模型是基于±1-、±2-和±3-mm的后向PCO模型以及基于每个PCO模型的-3°、0°、+3°和+6°PTS模型开发的。
随着PTS增加，最大PF接触应力、侧副韧带力和股四头肌力量降低。此外，随着PCO向后移位，最大PF接触应力和股四头肌力量降低，而侧副韧带力增加。这种趋势在任何PCO和PTS中都是一致的。
我们的研究结果显示了PCO和PTS术后改变对活动平台TKA生物力学结果的各种影响。基于计算模拟，我们建议骨科医生在活动平台TKA手术中保留患者自身的解剖学PCO和PTS。
