Three dimensional fit and full analysis and three dimensional non-linear finite element analysis of newly designed femoral stems in cementless total hip arthroplasty.

在全髋关节置换术中，股骨管的配合和填充是无骨水泥股骨干成功的关键。对于继发性骨关节炎患者，传统的骨柄很难提供良好的配合和填充。我们设计了两种具有近侧耀斑的Fukui Medical School （FMS）干，其内侧半径不同。我们使用计算机模拟和非线性三维有限元分析（ADINA6.1软件）比较了新设计的假体与传统假体的配合和填充、假体与骨的相对运动量以及向股骨的载荷转移。FMS支架的近端配合度和总配合度平均分别为46%和53%，与其他支架相比有显著提高。FMS柄的下、小转子的平均填充率为82%，峡端上端的平均填充率为84%，明显高于其他柄。与传统支架相比，FMS显示更少的近端侧向相对运动和更多的负荷转移到股骨近端（omniifit）。这表明FMS在术后早期对继发性骨关节炎的股骨具有更好的适应性和生物力学稳定性。

The fit and fill of the femoral canal are critical to the success of cementless femoral stems in total hip arthroplasty. It is difficult for conventional stems to provide a good fit and fill for the femora of patients with secondary osteoarthritis. We designed two types of Fukui Medical School (FMS) stem with a proximal lateral flare that were different in the medial radius. We compared the fit and fill, the amount of stem-bone relative motions, and load transfer to the femur among the newly designed stems and conventional stems, using a computer simulation and non-linear 3-D finite element (FE) analysis (ADINA6.1 software). The mean proximal fit and total fit of the FMS stems were 46% and 53% respectively, with a significant improvement compared with other stems. The mean fill of FMS stems was 82% at the lower and of the lesser trochanter and 84% at the upper end of the isthmus, which were significantly higher than those of other stems. The FMS showed less proximal lateral relative motion and more load transfer to the proximal femur compared with conventional stem (Omnifit).It suggests that the FMS will be expected to have a better adaptation of the femur with secondary osteoarthritis and biomechanical stability than conventional stems in early postoperative period.