Walker P S, Culligan S G, Hua J, Muirhead-Allwood S K, Bentley G
Centre for Biomedical Engineering, University College London, Royal National Orthopaedic Hospital Trust, United Kingdom.
Clin Orthop Relat Res. 2000 Apr(373):164-73. doi: 10.1097/00003086-200004000-00020.
Three types of uncemented femoral stems were designed for patients having revision hip surgery, with the goals of promoting axial stability and preserving proximal bone stock. These stems were made individually using computer design and manufacturing technology. Various design features were examined using nonlinear finite element analysis. All stems had lateral, medial, and anterior flares in the proximal region, proximal hydroxyapatite coating, and a collar. Based on a published classification system, the three designs were found suitable for variously encountered cavitary defects. For cases involving small amounts of bone destruction, a primary type of stem was used. With severe cases, an extended polished stem was used. For the worst cases, an extended stem with longitudinal cutting flutes and complete hydroxyapatite coating was necessary. The axial migration was measured radiographically for a 2-year period. The migration rates were comparable with those seen in cemented primary and in custom primary hydroxyapatite coated stems. Dual energy x-ray absorptiometry data were obtained during a 4-year postoperative period. Average bone density in all regions was maintained within 12% of the immediate postoperative values. It was concluded that the proposed system for treating patients needing revision hip surgery showed desirable properties that were comparable to primary hip replacements.
为接受髋关节翻修手术的患者设计了三种非骨水泥型股骨柄，目的是提高轴向稳定性并保留近端骨量。这些股骨柄采用计算机设计和制造技术单独制作。使用非线性有限元分析检查了各种设计特征。所有股骨柄在近端区域均有外侧、内侧和前侧扩口、近端羟基磷灰石涂层以及一个颈圈。根据已发表的分类系统，发现这三种设计适用于各种不同的腔隙性缺损情况。对于涉及少量骨质破坏的病例，使用一种主要类型的股骨柄。对于严重病例，使用延长的抛光股骨柄。对于最严重的病例，则需要使用带有纵向切割凹槽和完整羟基磷灰石涂层的延长股骨柄。通过影像学方法测量了两年期间的轴向移位情况。移位率与骨水泥型初次置换和定制初次羟基磷灰石涂层股骨柄的移位率相当。在术后四年期间获取了双能X线吸收法数据。所有区域的平均骨密度维持在术后即刻值的12%以内。得出的结论是，所提出的用于治疗需要髋关节翻修手术患者的系统显示出与初次髋关节置换相当的理想特性。
