Abstract

Image-free navigation has been proven as reliable as that using computed tomography (CT) in positioning the acetabular cup in total hip arthroplasty (THA), but previous studies rarely included hip dysplasia cases. The purpose of the present study was to determine the accuracies of CT-based navigation and image-free navigation for acetabular cup insertion, including hip dysplasia cases. Sixty-three hips were studied, including 57 with hip dysplasia. The hips were divided into two groups based on the registration point of image-free navigation. In Group I, the ipsilateral anterior superior iliac spine (ASIS) and the L5 spinous process were registered in 31 hips. In Group II, bilateral ASIS points were registered in 32 hips. Final component orientation was measured from postoperative CT scans. The accuracy of cup orientation was compared between CT-based and image-free navigation. In Group I, the cup inclination was more accurate with CT-based navigation (1.9°) than with image-free navigation (4.4°, p=.009). Cup anteversion was also more accurate with CT-based navigation (2.9°) than with image-free navigation (7.1°, p<.001). In Group II, the accuracies of cup inclination and anteversion showed no differences between CT-based and image-free navigation. The accuracy of cup positioning was better with CT-based navigation than with image-free navigation when the ipsilateral ASIS and L5 spinous process were digitized. However, accuracy was similar when bilateral ASIS points were digitized.

摘要

无图像导航已被证明与使用计算机断层扫描 (CT) 在全髋关节置换术 (THA) 中定位髋臼杯一样可靠，但以前的研究很少包括髋关节发育不良病例。本研究的目的是确定基于 CT 的导航和无图像导航在髋臼杯插入中的准确性，包括髋关节发育不良病例。研究了 63 个髋关节，其中 57 个髋关节发育不良。根据无图像导航的配准点将臀部分为两组。在第一组中，同侧髂前上棘 (ASIS) 和 L5 棘突在 31 髋中登记。在第二组中，双侧 ASIS 点记录在 32 个髋关节中。从术后 CT 扫描测量最终组件方向。在基于 CT 的导航和无图像导航之间比较了杯定位的准确性。在第一组中，基于 CT 的导航 (1.9°) 比无图像导航 (4.4°,p =.009）。基于 CT 的导航（2.9°）比无图像导航（7.1°， p <.001）更准确。在第 II 组中，基于 CT 和无图像导航的杯倾角和前倾精度没有差异。当同侧 ASIS 和 L5 棘突被数字化时，基于 CT 的导航比无图像导航的杯定位精度更好。然而，当双边 ASIS 点被数字化时，准确性是相似的。