Clinical Trial of a motion analyzing system using skeletal models including bone and muscle for prevention of postoperative dislocation after total hip arthroplasty

假体撞击是THA术后脱位的主要原因。然而，很难具体地确定每个患者的可引起的撞击。我们开发了一种新的全髋关节置换术后真实的实时四维运动分析系统，并将其用于术后脱位的保守治疗和手术治疗，在该系统中，骨骼和植入物的三维模型由患者的表面标记，用于后续的运动捕获。通过在三维运动分析器中实时跟踪这些标记，这些模型可以与任何患者的运动同步。对于脱位患者，在模拟脱位运动过程中，利用该系统可以检测到撞击部位。我们可以告知患者他们必须限制哪些运动以防止进一步脱位。在复发性脱位患者的翻修手术中，我们可以模拟适当的植入物方向，以解决该系统检测到的可引起的撞击。术前计划可通过导航系统实施。我们进行了两次翻修手术，两个回收髋臼杯在聚乙烯内衬边缘都有标记。该系统可准确地提供可引起撞击的重要信息，为预防和治疗THA术后脱位提供重要依据。

Prosthetic impingement is a major cause of dislocation after THA. However, it is difficult to identify the causable impingement for each patient concretely. We developed a novel system of real time four-dimensional motion analysis after THA and used it for conservative and operative treatment for postoperative dislocation.In this system, the skeletal and implant three-dimensional models were made from CT images of the patients with surface markers for following motion capture. These models could be synchronized with any patient's motions by real-time tracking of those markers in a three-dimensional motion analyzer. A warning can be given just before the collision between implant models.For the patients with dislocation, we can detect an impingement site using this system during the simulating motion in which they had experienced the dislocation. And we could inform the patients which motion they must limit for prevent further dislocation. In revision surgery for patients with recurrent dislocation, we can simulate appropriate implant orientation to resolve the causable impingement detected by this system. The preoperative planning can be put into practice by navigation system. We performed two revision surgeries, and both retrieval cups had a mark at the rim of the polyethylene liner. The location was closely consisted with the finding of impingement site detected by this system.This system might correctly provide important information of causable impingement for prevention and treatment of dislocation after THA.