Bartoska Radek, Baca Vaclav, Horak Zdenek, Hrubina Maros, Skala-Rosenbaum Jiri, Marvan Jiri, Kachlik David, Dzupa Valer
Department of Orthopaedy and Traumatology, Third Faculty of Medicine, Charles University in Prague and University Hospital Kralovske Vinohrady, Prague, Czech Republic.
Department of Health Care Studies, Colleague of Polytechnics Jihlava, Tolsteho 16, 586 01, Jihlava, Czech Republic.
Surg Radiol Anat. 2016 Jul;38(5):577-85. doi: 10.1007/s00276-015-1595-4. Epub 2015 Dec 8.
Proximal femoral fractures are among the most commonly sustained fractures. The current treatment of stable proximal femoral fractures located in trochanteric region primarily involves the use of two systems: extramedullary dynamic hip screws and intramedullary hip nails. Given that these fractures are mainly found in the elderly population, the necessity of a repeat, due to failure of the first, may jeopardize the patient's life. Decisive factors contributing to the healing of a fracture (or the failure thereof) include fracture pattern, technical implementation of the operation (i.e., position of the implant), implant's properties and its changes in relation to the surrounding bone tissue during loading. Each screw insertion variant results in damage to various load-bearing bone structures, which can be expected to influence healing quality and stability of newly formed bone.
With the aid of a numerical model and finite element methods, the authors analyzed several different positions of IMHN/PFH-nails in the proximal femur, with the objective of determining positions with an increased risk of failure.
In model situations, it has been shown that in stable fractures results do not depend on absolutely precise positioning and small deflections in the nails and neck screws positions do not significantly increase the risk of failure for the entire fixation. Damage to load-bearing structures relative to various implant placements does not impact the resultant overall fixation stability. Therefore, it is not necessary to re-introduce implants in the ideal position, which can lead to reduced patient radiation doses during surgery.
股骨近端骨折是最常见的骨折类型之一。目前，对于位于转子区的稳定型股骨近端骨折，主要采用两种治疗系统：髓外动力髋螺钉和髓内髋螺钉。鉴于这些骨折主要发生在老年人群中，首次治疗失败后再次治疗的必要性可能会危及患者生命。影响骨折愈合（或不愈合）的决定性因素包括骨折类型、手术技术实施（即植入物位置）、植入物特性及其在加载过程中与周围骨组织的相互变化。每种螺钉置入方式都会对不同的承重骨结构造成损伤，这可能会影响新形成骨的愈合质量和稳定性。
作者借助数值模型和有限元方法，分析了髓内髋螺钉/近端股骨防旋髓内钉（IMHN/PFH-nails）在股骨近端的几种不同位置，目的是确定失败风险增加的位置。
在模型情况下，已表明在稳定骨折中，结果并不取决于绝对精确的定位，并且钉和颈螺钉位置的小偏差不会显著增加整个固定的失败风险。相对于各种植入物位置的承重结构损伤不会影响最终的整体固定稳定性。因此，无需将植入物放置在理想位置，这可减少手术期间患者的辐射剂量。
