Femoral stem neck geometry determines hip range of motion shape : a computer simulation study.
Femoral stem neck geometry determines hip range of motion shape : a computer simulation study.
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DOI：
10.1302/2046-3758.1012.bjr-2021-0273.r1
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发表时间：
2021-12
影响因子：
4.6
通讯作者：
Schwarzkopf R
中科院分区：
文献类型：
--
作者：
Eslam Pour A;Lazennec JY;Patel KP;Anjaria MP;Beaulé PE;Schwarzkopf R
在计算机模拟中，具有圆柱形颈部设计的股骨柄的活动范围（ROM）形状将是完美的圆锥体。然而，许多现代股骨柄具有矩形/椭圆形颈。我们假设矩形/椭圆形股骨柄颈将影响ROM的形状和假体撞击。使用MATLAB模型（一个股骨柄为圆柱形股骨颈，一个股骨柄为矩形股骨颈）模拟站立和坐姿时的全髋关节置换术（THA）运动。主要预测因素是股骨颈的几何形状（圆柱形vs矩形），主要结局是基于股骨颈和内衬之间假体撞击的ROM形状。次要结果是每个颈部几何形状提供的ROM的差异以及骨盆倾斜对此ROM的影响。多元回归用于分析数据。与圆柱形股骨颈中的圆锥体相比，矩形股骨颈股骨柄具有更大的内旋和外旋，具有四叶形横截面。髋臼杯方向和骨盆倾斜度的改变影响了圆锥形或四叶形的投影方向。矩形股骨颈的内旋平均增加3.4°（0°至7.9°; p < 0.001）;外旋平均增加2.8°（0.5°至7.8°; p < 0.001）。我们的研究显示了关注股骨植入物设计对评估假体撞击的重要性。任何忽略每个股骨柄独特的股骨颈几何形状的通用数学模型或计算机模拟都将提供不准确的假体撞击预测。引用这篇文章：骨关节研究2021;10（12）：780-789。
In computer simulations, the shape of the range of motion (ROM) of a stem with a cylindrical neck design will be a perfect cone. However, many modern stems have rectangular/oval-shaped necks. We hypothesized that the rectangular/oval stem neck will affect the shape of the ROM and the prosthetic impingement. Total hip arthroplasty (THA) motion while standing and sitting was simulated using a MATLAB model (one stem with a cylindrical neck and one stem with a rectangular neck). The primary predictor was the geometry of the neck (cylindrical vs rectangular) and the main outcome was the shape of ROM based on the prosthetic impingement between the neck and the liner. The secondary outcome was the difference in the ROM provided by each neck geometry and the effect of the pelvic tilt on this ROM. Multiple regression was used to analyze the data. The stem with a rectangular neck has increased internal and external rotation with a quatrefoil cross-section compared to a cone in a cylindrical neck. Modification of the cup orientation and pelvic tilt affected the direction of projection of the cone or quatrefoil shape. The mean increase in internal rotation with a rectangular neck was 3.4° (0° to 7.9°; p < 0.001); for external rotation, it was 2.8° (0.5° to 7.8°; p < 0.001). Our study shows the importance of attention to femoral implant design for the assessment of prosthetic impingement. Any universal mathematical model or computer simulation that ignores each stem’s unique neck geometry will provide inaccurate predictions of prosthetic impingement. Cite this article: Bone Joint Res 2021;10(12):780–789.