Service of Orthopedics and Traumatology, Lausanne University Hospital and University of Lausanne, Avenue Pierre-Decker 4, 1011 Lausanne, Switzerland.
Laboratory of Biomechanical Orthopedics, Ecole Polytechnique Fédérale de Lausanne, Station 09, 1015 Lausanne, Switzerland.
Med Eng Phys. 2024 Sep;131:104230. doi: 10.1016/j.medengphy.2024.104230. Epub 2024 Aug 13.
There is currently no definitive evidence for the implant of choice for the treatment of reverse pertrochanteric fractures. Here, we aimed to compare the stability provided by two implant options: long and short intramedullary nails. We performed finite element simulations of different patterns of reverse pertrochanteric fractures with varying bone quality, and compared the short vs long nail stabilization under physiological loads. For each variable combination, the micromotions at the fracture site, bone strain, and implant stress were computed. Mean micromotions at the fracture surface and absolute and relative fracture surface with micromotions >150 µm were slightly lower with the short nail (8%, 3%, and 3%, respectively). The distal fracture extension negatively affected the stability, with increasing micromotions on the medial side. Bone strain above 1 % was not affected by the nail length. Fatigue stresses were similar for both implants, and no volume was found above the yield and ultimate stress in the tested conditions. This simulation study shows no benefit of long nails for the investigated patterns of reverse pertrochanteric fractures, with similar micromotions at the fracture site, bone strain, and implant stress.
目前对于治疗反转子间骨折，哪种植入物是首选还没有明确的证据。在这里，我们旨在比较两种植入物选择（长和短髓内钉）提供的稳定性。我们对不同骨质量的反转子间骨折进行了有限元模拟，并比较了在生理负荷下短钉与长钉的稳定情况。对于每种变量组合，计算了骨折部位的微动、骨应变和植入物的应力。短钉的骨折表面的平均微动（分别为 8%、3%和 3%）和绝对和相对微动>150µm 的骨折表面（分别为 3%、3%和 3%）略低。远端骨折延伸对线不良会降低稳定性，内侧的微动会增加。钉的长度不影响 1%以上的骨应变。两种植入物的疲劳应力相似，在测试条件下，没有发现屈服强度和极限强度以上的体积。这项模拟研究表明，对于所研究的反转子间骨折模式，长钉并没有优势，骨折部位、骨应变和植入物的应力相似。
