Hart Alister J, Dandachli Wael, Schlueter-Brust Klaus, Henckel Johann, Cobb Justin
Department of Musculoskeletal Surgery, Imperial College London, Charing Cross Hospital Campus, London, UK.
Hip Int. 2009 Oct-Dec;19(4):323-9. doi: 10.1177/112070000901900405.
CT when compared to plain radiograph is known to be a more valid measure of acetabular component orientation. The validity of plain radiographs may be further compromised by large diameter metal femoral heads because of obscuration of the acetabular rim. We quantified this effect by measuring acetabular cup angles (inclination and version) of 49 metal on metal (MOM) hip resurfacings using plain radiographs and 3D CT based measurement. Bland-Altman plots revealed poor agreement between plain radiographic and CT based measurement with 2 standard deviation limits of agreements of: +7 to -15 degrees for cup inclination angle; and +16 to -31 degrees for cup version angle. The large differences between plain radiographic and CT measurement of cup positions are probably due to the large diameter metal femoral head that can obscure the cup margin. We have used a metal artefact reduction CT protocol with a 3D imaging software package to overcome this problem and measure cup position relative to the Anterior Pelvic Plane.
与普通X线片相比，CT被认为是测量髋臼假体组件方向更有效的方法。由于髋臼边缘被遮挡，大直径金属股骨头可能会进一步影响普通X线片的有效性。我们通过使用普通X线片和基于3D CT的测量方法，对49例金属对金属（MOM）髋关节表面置换术的髋臼杯角度（倾斜度和旋转度）进行量化，以评估这种影响。Bland-Altman图显示，普通X线片测量与基于CT的测量之间的一致性较差，一致性的2个标准差范围为：髋臼杯倾斜角为+7至-15度；髋臼杯旋转角为+16至-31度。普通X线片与CT测量髋臼杯位置的巨大差异可能是由于大直径金属股骨头会遮挡髋臼杯边缘。我们使用了一种带有3D成像软件包的金属伪影减少CT方案来克服这个问题，并测量髋臼杯相对于骨盆前平面的位置。
