Han Shuyang, Mascarenhas Daniel C, Pletka Camryn A, Gold Jonathan E, Ismaily Sabir K, Cao Matthew, Brewer Matthew W, Frangie Robert, Noble Philip C, Rodriguez-Quintana David
Department of Orthopedic Surgery, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas.
J Arthroplasty. 2025 Sep;40(9S1):S564-S570. doi: 10.1016/j.arth.2025.04.064. Epub 2025 May 6.
Tapered fluted stems are an excellent solution for revision hip arthroplasty following periprosthetic fractures. However, existing implant designs differ in terms of the number of splines, taper angle, and cross-sectional design, and there is a lack of knowledge on the biomechanical effect of these design variations. Therefore, the objective of this study was to compare the primary stability of two representative stem designs and the extent and distribution of stem-bone contact in a periprosthetic fracture model. It was hypothesized that a greater number of splines would lead to greater stability.
There were six pairs of cadaver femora included and underwent computed tomography imaging for templating. An extended trochanteric osteotomy was created and then reduced using three cerclage cables. Subsequently, one femur in each pair was implanted with 1 of 2 commercial designs of tapered fluted stems. During specimen preparation, the position and orientation of the reamer and the stems were measured by laser scanning, allowing measurement of stem-bone contact. Subsequently, each specimen was subjected to 1,000 cycles of biomechanical loading tests, and stem-bone motion was measured using a motion capture system.
The average subsidence of the two stems after loading was 313 ± 138 and 181 ± 113 μm (P > 0.05). The largest micromotion during each loading-unloading cycle was observed in the first cycle for both stems, and it remained constant in the subsequent cycles. There was more anterior stem-bone contact than posterior region in both stems, and the average contact area was comparable (1,546 ± 533 and 1,525 ± 587 mm, P > 0.05).
Different geometric designs did not lead to significant changes in the extent and distribution of stem-bone contact, and both stems demonstrated similar primary stability under the loads tested in this study.
锥形带槽柄对于假体周围骨折后的髋关节翻修置换术是一种很好的解决方案。然而，现有的植入物设计在花键数量、锥角和横截面设计方面存在差异，并且对于这些设计变化的生物力学效应缺乏了解。因此，本研究的目的是比较两种代表性柄设计的初始稳定性以及在假体周围骨折模型中柄与骨接触的范围和分布。研究假设是花键数量越多稳定性越高。
纳入六对尸体股骨并进行计算机断层扫描成像以进行模板制作。进行大转子延长截骨术，然后用三根环扎钢缆进行复位。随后，每对中的一根股骨植入两种市售锥形带槽柄设计中的一种。在标本制备过程中，通过激光扫描测量铰刀和柄的位置及方向，从而能够测量柄与骨的接触情况。随后，对每个标本进行1000次循环的生物力学加载测试，并使用运动捕捉系统测量柄与骨的运动。
加载后两种柄的平均下沉量分别为313±138和181±113μm（P>0.05）。两种柄在每个加载-卸载循环中的最大微动均在第一个循环中观察到，并且在随后的循环中保持恒定。两种柄的前侧柄与骨接触均多于后侧区域，且平均接触面积相当（1546±533和1525±587mm，P>0.05）。
不同的几何设计并未导致柄与骨接触的范围和分布发生显著变化，并且在本研究测试的载荷下两种柄均表现出相似的初始稳定性。
