计算机模拟全髋关节置换术后假体位置对关节活动的影响

目的　通过计算机模拟全髋关节置换术，研究假体位置对关节活动度及稳定性的影响。 方法　以CT数据为基础，利用计算机三维重建及虚拟手术技术建立全髋关节置换术后三维模型，在不同假体位置模拟关节运动并测量关节发生撞击前的最大活动范围。 结果　(1)髋臼外展角增大可导致屈、伸、屈曲90°内旋活动范围增大，对外旋影响小；髋臼及股骨前倾角增大均可导致屈及屈90°内旋活动范围增大，而伸及外旋均减小。(2)为满足日常活动需要，取较大髋臼外展角时，髋臼前倾角宜适当减小；取较小髋臼前倾角时，股骨前倾角宜适当增大，反之亦然；而髋臼外展角与股骨前倾角的相对位置取决于髋臼前倾角。 结论　在全髋关节置换术中，把握好假体的相对位置可改善关节活动范围，增加关节稳定性。此外，本结果对髋关节假体翻修术中假体安放及术后脱位患者日常活动范围具有重要的指导意义。

Effects of the position of the components on hip motion in the virtual total hip replacement

Objective To explore the effects of the position of components on hip joint motion in the virtual total hip replacement.Methods Based on digital CT images,a three-dimensional computer model of the hip after total hip replacement were created by the use of computer three-dimensional reconstruction and virtual surgery technology.The model was designed to simulate joint motion and get maximum range of motion before joint impingement at different positions.Results(1) Excerpt for the range of external rotation,the increase of acetabular abduction induced the increase of the range of flexion,extension and internal rotation at 90° flexion.The increase of the acetabular and femoral anteversion induced the increase of the range of flexion and internal rotation at 90° flexion,but the decrease of the range of extension and external rotation.(2) To meet the needs of daily activities,the greater acetabular abduction required appropriately decreased acetabular anteversion.The relative position of acetabular abduction and femoral anteversion depended on the acetabular anteversion.Conclusions It’s important to confirm the relative position of the components during the total hip replacement.Furthermore,this result is valuable for guiding the prosthesis implantation in reversion surgery and the range of daily activities in patients with postoperative dislocation.