全膝关节置换假体尺寸和植入位置对股骨胫骨相对位移的影响

The effects of the size and implant position of total knee arthroplasty prosthesis on the relative displacement between femur and tibia

目的研究人工膝关节置换后不同膝关节假体尺寸和植入位置对膝关节股骨胫骨相对位移的影响,以期为临床手术方式的选择提供参考。方法使用健康受试者和膝骨关节炎(knee osteoarthritis,KOA)患者的术前CT和MRI数据,建立有限元模型。采集受试者步态参数和地面反作用力,使用三维动态捕捉系统和三维测力台同步采集数据。使用四号、六号和八号PS型假体在有限元模型上模拟人工膝关节置换,将胫骨假体向关节内外各移动1 mm,分析不同假体尺寸和植入位置在站立位、地面反作用力第一峰值和第二峰值时刻的股骨胫骨相对位移。结果在健康受试者模型中,股骨胫骨相对位移极值分别为0.43 mm和0.30 mm。在KOA患者模型中,假体植入位置和假体尺寸都会影响股骨胫骨相对位移。当股骨假体植入中心位置时,不同假体尺寸的股骨和胫骨相对位移峰值不同。当股骨假体向外或向内移动1 mm时,股骨和胫骨之间的相对位移峰值也不同。结论假体中立位植入股骨胫骨相对位移最小。术前对假体尺寸和植入位置进行合理分析和规划有助于提高临床手术效果,医生应尽量避免假体植入偏向膝关节内侧。

Objective To study the effects of different sizes and implantation positions of knee joint prostheses on the relative displacement of the tibia and femur after artificial knee joint replacement,and to provide a reference for clinical surgical selection.Methods Finite element models were established using preoperative CT and MRI data from healthy subjects and patients with knee osteoarthritis(KOA).Gait parameters and ground reaction forces were collected from subjects,and data were synchronized using a 3D motion capture system and a 3D force plate.PS-type prostheses with sizes 4,6,and 8 were used to simulate artificial knee joint replacement on the finite element model.The tibial prosthesis was moved 1 mm inward and outward,and the relative displacement of the tibia and femur was analyzed at the time of standing,the first peak of the ground reaction force,and the second peak of the ground reaction force.Results In the healthy subject model,the maximum relative displacement between the tibia and femur was 0.43 mm and 0.30 mm,respectively.In the KOA patient model,implantation positions and sizes of prostheses affected the relative displacement of the tibia and femur.When the femoral prosthesis was implanted in the center position,the peak relative displacement between the femur and tibia was different for different prosthesis sizes.When the femoral prosthesis was moved 1 mm inward or outward,the peak relative displacement between the femur and tibia also varied.Conclusions Neutral implantation of the prosthesis in the femur and tibia resulted in the smallest relative displacement.Reasonable analysis and planning of prosthesis size and implantation position prior to surgery can help improve clinical outcomes,and doctors should try to avoid implanting the prosthesis toward the medial side of the knee joint.