Bragdon Charles R, Estok Daniel M, Malchau Henrik, Kärrholm Johan, Yuan Xunhua, Bourne Robert, Veldhoven Jean, Harris William H
Orthopaedic Biomechanics and Biomaterials Laboratory, Adult Reconstructive Unit, Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, 1126 Fruit Street, Jackson Building, Boston, MA 02114, USA.
J Orthop Res. 2004 May;22(3):659-64. doi: 10.1016/j.orthres.2003.09.004.
Radiostereometric analysis (RSA) has been used extensively to evaluate the magnitude and direction of penetration of the femoral head into the acetabular component of a total hip replacement as a result of polyethylene wear and creep. The accuracy and precision of an RSA study depends on several factors, including the radiographic technique, the analytical software, and the positioning of the tantalum markers. This study had three sequential purposes. First, an in vitro phantom model was used to quantify the accuracy and precision of digital images versus conventional radiography in RSA measurements of penetration of the femoral head into the acetabular shell in a total hip replacement. The Umeå RSA software package was used for analysis of both the conventional films, which were digitized at a resolution of 300 DPI, and digital radiographs, which were converted from a DICOM format at a resolution of 218 DPI. Digital radiography was found to be superior. Next, two methods of RSA analysis currently in use for determining femoral head penetration into polyethylene of total joint replacements were compared. Using the phantom model, we compared the Umeå RSA system (Biomedical Innovations AB) to the RSA-CMS (RSA Clinical Measurement Solution) and in both cases used the digital radiographs. The Umeå RSA system was found to be superior. Finally, two methods of marking the position of the acetabular component with tantalum beads were compared: one in which beads were inserted into previously described towers protruding from the back of the acetabular shell and another in which beads were placed into the peripheral flange of the polyethylene liner using the Umeå RSA analysis system of the digital radiographs. The results using the two marker configurations were similar.
放射立体测量分析（RSA）已被广泛用于评估由于聚乙烯磨损和蠕变导致的全髋关节置换中股骨头向髋臼组件的穿透程度和方向。RSA研究的准确性和精确性取决于几个因素，包括放射成像技术、分析软件以及钽标记物的定位。本研究有三个连续的目的。首先，使用体外模型来量化在全髋关节置换中股骨头向髋臼壳穿透的RSA测量中，数字图像与传统放射成像相比的准确性和精确性。于默奥RSA软件包用于分析分辨率为300 DPI的传统胶片（这些胶片被数字化）以及分辨率为218 DPI的从DICOM格式转换而来的数字射线照片。结果发现数字射线照片更具优势。其次，比较了目前用于确定全关节置换中股骨头向聚乙烯穿透的两种RSA分析方法。使用模型，我们将于默奥RSA系统（生物医学创新公司）与RSA - CMS（RSA临床测量解决方案）进行了比较，两种情况均使用数字射线照片。结果发现于默奥RSA系统更具优势。最后，比较了用钽珠标记髋臼组件位置的两种方法：一种是将珠子插入从髋臼壳背面突出的先前描述的塔状物中，另一种是使用数字射线照片的于默奥RSA分析系统将珠子放置在聚乙烯衬垫的周边凸缘中。两种标记配置的结果相似。
