Polyclinique du Parc, Cholet, France.
J Arthroplasty. 2013 Sep;28(8):1437-45. doi: 10.1016/j.arth.2013.01.010. Epub 2013 Mar 13.
When a stemmed TKA is needed in a femur in which a THA is already present, choosing an appropriate length for the TKA stem is crucial. Many surgeons intuitively fear that the distance between the stem tips correlates with the femur risk for fracture (RF). However, to date, no biomechanical data to support this intuition are available. Therefore, in this study, the RF in such a configuration was determined and compared for several activities, using a finite element modeling technique. During gait and sideways falling no difference in RF among different stem lengths was shown. However, a clear threshold appears during four-point bending. Stem tip distances shorter than 110 mm dramatically increased RF and, in osteoporotic bone, will certainly lead to fracture (RF>1) and thus should be avoided.
当需要在已经存在髋关节置换术 (THA) 的股骨中进行带柄全膝关节置换术 (TKA) 时，选择合适长度的 TKA 柄至关重要。许多外科医生直觉上担心柄尖端之间的距离与股骨骨折风险 (RF) 相关。然而，迄今为止，尚无支持这种直觉的生物力学数据。因此，在这项研究中，使用有限元建模技术确定并比较了这种情况下的 RF ，并比较了几种活动。在步态和侧倒时，不同柄长度之间的 RF 没有差异。然而，在四点弯曲时出现了明显的阈值。柄尖端距离短于 110 毫米会显著增加 RF ，在骨质疏松性骨中，肯定会导致骨折 (RF>1) ，因此应避免使用。
