Panagopoulos Andreas, Kyriakopoulos Georgios, Anastopoulos Georgios, Megas Panagiotis, Kourkoulis Stavros K
Orthopaedic Department, Patras University Hospital, Patras-Rio, Greece.
First Department of Trauma and Orthopaedics, General Hospital of Athens, Athens, Greece.
JMIR Res Protoc. 2019 Jul 18;8(7):e12845. doi: 10.2196/12845.
Intertrochanteric hip fractures rank in the top 10 of all impairments worldwide in terms of loss in disability-adjusted years for people aged older than 60 years. The type of surgery is usually carried out with dynamic hip screw (DHS) devices or cephalomedullary nails (CMN). Cut-out of the hip screw is considered the most frequent mechanical failure for all implants with an estimated incidence ranging from 2% to 16.5%; this entails both enhancing our understanding of the prognostic factors of cut-out and improving all aspects of intertrochanteric fracture treatment.
The Design of Improved Intertrochanteric Fracture Treatment (DRIFT) study's main objective is to provide intertrochanteric fracture treatment expertise, requirements and specifications, clinical relevance, and validation to improve treatment outcomes by developing a universal algorithm for designing patient- and fracture-oriented treatment. The hypothesis to be tested is that a more valgus reduction angle and implants of higher angles will lead to a more favorable biomechanical environment for fracture healing-that is, higher compressive loads at the fracture site with lower shear loads at the hip screw femoral head interface. A new implant with enhanced biomechanical and technical characteristics will be designed and fabricated; in addition, an integrated design and optimization platform based on computer-aided design tools and topology optimization modules will be developed.
To test this hypothesis, a biomechanical study comprising experimental loading of synthetic femora (Sawbones Inc) and finite element analysis (FEA) will be conducted. Detailed FEA of existing implants (DHS and CMN) implemented in different clinical cases under walking conditions will be performed to derive the stress and strain fields developed at the implant-bone system and identify critical scenarios that could lead to failure of therapy. These models would be validated against instrumented mechanical tests using strain gages and a digital image correlation process.
After testing, geometric drawbacks of existing implants will be fully recognized, and geometric characteristics will be correlated with critical failure scenarios. The last step would be the numeric design, computer-aided design (using FEA codes and design packages), and optimization of the new proposed implant with regard to improved biomechanical surgical technique and enhanced mechanical performance that will reduce the possibility for critical failure scenarios.
The optimization of the biomechanical behavior of the fracture-osteosynthesis model by the application of the ideal reduction angle and implant is expected to have a positive effect to the rate of mechanical failure and, subsequently, the healing rates, morbidity, and mortality in this fragile patient group.
INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/12845.
在全球范围内，对于60岁以上的人群，粗隆间髋部骨折在伤残调整生命年损失方面位列所有损伤的前10位。手术类型通常采用动力髋螺钉（DHS）装置或髓内钉（CMN）。髋螺钉穿出被认为是所有植入物最常见的机械故障，估计发生率在2%至16.5%之间；这就需要我们加深对穿出预后因素的理解，并改善粗隆间骨折治疗的各个方面。
改进型粗隆间骨折治疗设计（DRIFT）研究的主要目的是通过开发一种通用算法来设计以患者和骨折为导向的治疗方案，从而提供粗隆间骨折治疗的专业知识、要求和规范、临床相关性以及验证，以改善治疗效果。待检验的假设是，更大的外翻复位角度和更高角度的植入物将为骨折愈合带来更有利的生物力学环境，即骨折部位有更高的压缩载荷，而髋螺钉股骨头界面处的剪切载荷更低。将设计并制造一种具有增强生物力学和技术特性的新型植入物；此外，还将开发一个基于计算机辅助设计工具和拓扑优化模块的集成设计与优化平台。
为检验这一假设，将进行一项生物力学研究，包括对合成股骨（Sawbones公司）进行实验加载和有限元分析（FEA）。将对在不同临床病例中行走条件下使用的现有植入物（DHS和CMN）进行详细的有限元分析，以得出植入物 - 骨系统中产生的应力和应变场，并识别可能导致治疗失败的关键情况。这些模型将通过使用应变片和数字图像相关过程的仪器化机械测试进行验证。
测试后，将充分认识到现有植入物的几何缺陷，并将几何特征与关键失败情况相关联。最后一步将是对新提出的植入物进行数值设计、计算机辅助设计（使用有限元分析代码和设计软件包）以及优化，以改进生物力学手术技术并提高机械性能，从而降低关键失败情况发生的可能性。
通过应用理想的复位角度和植入物来优化骨折内固定模型的生物力学行为，有望对这一脆弱患者群体的机械故障率以及随后的愈合率、发病率和死亡率产生积极影响。
国际注册报告识别码（IRRID）：DERR1 - 10.2196/12845。
