Bavil Alireza Y, Eghan-Acquah Emmanuel, Dastgerdi Ayda Karimi, Diamond Laura E, Barrett Rod, Walsh Henry Pj, Barzan Martina, Saxby David J, Feih Stefanie, Carty Christopher P
Griffith Center of Biomedical and Rehabilitation Engineering (GCORE), Griffith University, Australia; School of Health Sciences and Social Work, Griffith University, Australia; Advanced Design and Prototyping Technologies (ADaPT) Institute, Griffith University, Australia.
Griffith Center of Biomedical and Rehabilitation Engineering (GCORE), Griffith University, Australia; School of Health Sciences and Social Work, Griffith University, Australia; Department of Orthopaedics, Children's Health Queensland Hospital and Health Service, Australia.
Comput Biol Med. 2025 Feb;185:109544. doi: 10.1016/j.compbiomed.2024.109544. Epub 2024 Dec 16.
Proximal femoral osteotomy (PFO) is a surgical intervention, typically performed on paediatric population, that aims to correct femoral deformities caused by different pathologies (e.g., slipped capital femoral epiphysis). A PFO involves introduction of an implant to fix the proximal and distal sections of femur following the surgical corrections. The femoral neck-shaft angle (NSA) and anteversion angle (AVA) are key geometric parameters that influence PFO outcomes. To date, the effects of NSA and AVA on bone-implant system mechanics in paediatric populations have not been examined.
This study used an established neuromusculoskeletal modelling process paired with finite element analysis to determine the sensitivity of the implanted femur's mechanics to variations in NSA and AVA during the stance phase of walking. Three male patients aged 9-12 years with different pathology (Spastic diplegia, Perthes disease and Slipped Capital Femoral Epiphysis), weight (377, 747, 842 N), height (1.39, 1.55, 1.71 m) and femur lengths (34.1, 39.4, 43.7 cm) and geometries (NSA: 143, 102, 111 deg; AVA: 29, 17, -22 deg) were examined. For each patient, a three-dimensional bone model was created from computed tomography imaging and digital surgical corrections were applied to systematically vary the NSA and AVA. Personalized motion and loading conditions driven from a neuromusculoskeletal modelling process were applied to each model and its associated permutations of NSA and AVA.
Results indicated significant intra-participant variability in post-PFO bone-implant micromotion and peak von Mises stress on implant. For models with a post-surgery NSA of 135° and AVA of 12°, the averaged micromotion increased by 87 % and the peak von Mises stress decreased by 63% between patient 1 and 2. Between patient 2 and 3, the averaged micromotion decreased by 55% while the peak von Mises stress increased by 84%.
Furthermore, post-PFO bone-implant mechanics were sensitive to variation in NSA and AVA in a subject-specific manner. Optimization of PFO planning is recommended based on patient-specific characteristics.
股骨近端截骨术（PFO）是一种外科手术干预，通常针对儿童群体实施，旨在矫正由不同病理状况（如股骨头骨骺滑脱）引起的股骨畸形。PFO手术需要植入植入物，以便在手术矫正后固定股骨的近端和远端部分。股骨颈干角（NSA）和前倾角（AVA）是影响PFO手术效果的关键几何参数。迄今为止，尚未研究NSA和AVA对儿童群体骨植入系统力学的影响。
本研究采用既定的神经肌肉骨骼建模流程并结合有限元分析，以确定在步行站立阶段，植入股骨的力学性能对NSA和AVA变化的敏感性。研究了三名年龄在9至12岁之间、患有不同病症（痉挛性双侧瘫、佩特兹病和股骨头骨骺滑脱）、体重（377、747、842牛顿）、身高（1.39、1.55、1.71米）以及股骨长度（34.1、39.4、43.7厘米）和几何形状（NSA：143、102、111度；AVA：29、17、 -22度）的男性患者。对于每位患者，根据计算机断层扫描成像创建三维骨骼模型，并应用数字手术矫正来系统地改变NSA和AVA。将神经肌肉骨骼建模流程驱动的个性化运动和负荷条件应用于每个模型及其相关的NSA和AVA排列组合。
结果表明，PFO术后骨植入物的微动和植入物上的米塞斯应力峰值在受试者内部存在显著差异。对于术后NSA为135°且AVA为12°的模型，患者1和患者2之间的平均微动增加了87%，米塞斯应力峰值降低了63%。在患者2和患者3之间，平均微动降低了55%，而米塞斯应力峰值增加了84%。
此外，PFO术后骨植入物力学性能对NSA和AVA的变化具有个体特异性敏感性。建议根据患者的个体特征优化PFO手术规划。
