Olofsson Kent, Digas Georgios, Kärrholm Johan
Department of Orthopaedics, Sahlgrenska Hospital, Göteborg University, Sweden.
Clin Orthop Relat Res. 2006 Jul;448:67-72. doi: 10.1097/01.blo.0000224020.73163.28.
The clinical results of using different cemented stems in total hip arthroplasty may vary because of shape, surface finish, and choice of metal alloy. Less is known about the influence of size and offset using one and the same design. Data from 140 patients (140 hips) of a cohort constituting 197 patients (231 hips) implanted with cemented Spectron Primary stems were extracted from patients studied in four randomized studies primarily designed for other purposes. Stem size (1, 2, 3, or larger), normal/extra offset, neck length and true offset (horizontal length between the stem and head center of the inserted modular implant) were recorded in millimeters. The radiographic appearance of the cementing was graded on the immediate postoperative radiograph according to Barrack. The patients were examined with radiostereometric analysis of stem migration for a 2-year followup period. Stem Size 1 (the smallest) showed an insignificant increase in subsidence compared with the bigger sizes. Using stepwise linear regression analysis, the quality of the cementing (Barrack C2) was the only parameter that had any certain influence of the subsidence at 2 years. Stem size 2 tended to show minimum valgus alignment and sizes 1 and 3 and bigger showed minimum varus tilting. Our findings suggest that placement of the stem with the tip against the posterior cortex (C2) and stem size influence the primary fixation in different ways. This effect is small, however, indicating that further confirmation with longer followup is necessary.
Therapeutic Level II-1 (prospective cohort study). See the Guidelines for Authors for a complete description of levels of evidence.
在全髋关节置换术中使用不同的骨水泥型股骨柄，其临床结果可能因形状、表面光洁度和金属合金的选择而有所不同。对于使用同一设计时尺寸和偏心距的影响，人们了解得较少。从四项主要为其他目的设计的随机研究中选取了197例患者（231髋）中植入骨水泥型Spectron Primary股骨柄的140例患者（140髋）的数据。记录股骨柄尺寸（1、2、3或更大）、正常/额外偏心距、颈长和真实偏心距（植入的模块化假体的股骨柄与股骨头中心之间的水平长度），单位为毫米。根据Barrack标准，在术后即刻的X线片上对骨水泥填充的影像学表现进行分级。对患者进行为期2年的放射立体测量分析，以监测股骨柄的移位情况。与较大尺寸相比，尺寸1（最小）的下沉增加不显著。采用逐步线性回归分析，骨水泥填充质量（Barrack C2级）是对2年时下沉有一定影响的唯一参数。尺寸2的股骨柄倾向于显示最小的外翻对线，尺寸1、3及更大尺寸的股骨柄倾向于显示最小的内翻倾斜。我们的研究结果表明，股骨柄尖端靠在后侧皮质（C2）的放置方式和股骨柄尺寸以不同方式影响初次固定。然而，这种影响较小，表明需要更长时间的随访来进一步证实。
治疗性II-1级（前瞻性队列研究）。有关证据水平的完整描述，请参阅作者指南。
