Yang Peng, Liu Qi, Lin Tianye, Aikebaier Aobulikasimu, Jiang Luoyong, Sun Weichao, Zhang Qingwen, Bai Xueling, Sun Wei
Department of Orthopedics, Shenzhen Second People's Hospital, Shenzhen, Guangdong, China.
Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences (CAS), Shenzhen, Guangdong, China.
Front Bioeng Biotechnol. 2023 Jul 19;11:1171040. doi: 10.3389/fbioe.2023.1171040. eCollection 2023.
To investigate the early postoperative gait characteristics of patients who underwent periacetabular osteotomy (PAO) and predict the biomechanical performance of two commonly used PAO fixation methods: iliac screw (IS) and transverse screw (TS). A total of 12 patients with unilateral developmental dysplasia of the hip (DDH) (mean age 27.81 ± 4.64 years, 42% male) that were scheduled to undergo PAO surgery were included in this study. Their preoperative CT images and pre- and postoperative gait data were used to create subject-specific musculoskeletal models and complete the inverse dynamics analysis (IDA). Two patients with typical gait characteristics were selected using clustering analysis, and their IDA data were incorporated into finite element (FE) models of IS and TS fixations. Failure simulation was performed by applying iterative steps with increasing gait load to predict yield load. Stress results and yield loads were calculated for each FE model at different phases of the gait cycle. Postoperative gait showed improvement compared to preoperative gait but remained inferior to that of healthy individuals. Postoperative gait was characterized by a lower hip range of motion, lower peri-ilium muscle forces, particularly in the abductors, and a sharper initial peak and flatter second peak of hip joint reaction force (HRF). Finite element analysis (FEA) showed a trend of increasing stress during the second-fourth phases of the gait cycle, with lower stress levels in other phases. At high-stress gait phases, the mean stress of maximum differed significantly between IS and TS ( < 0.05) and between coupled and uncoupled muscle forces ( < 0.05). Failure analysis predicted a slightly larger yield load for TS configurations (6.21BW) than that for IS (6.16BW), but both were well above the gait load. Coupled and uncoupled groups showed similar results, but uncoupled groups had lower yield loads (5.9*BW). PAO early postoperative gait shows a normalized trend, but abnormalities persist. IS and TS are both capable of resisting mechanical strain failure, with no significant mechanical advantage found for transverse screw fixation during PAO early postoperative gait. Additionally, it is important to note that the TS may have a higher risk of cyclic fatigue failure due to the localized greater stress concentration. Furthermore, the most medial screw is crucial for pelvic stability.
为研究接受髋臼周围截骨术（PAO）患者术后早期的步态特征，并预测两种常用PAO固定方法：髂骨螺钉（IS）和横向螺钉（TS）的生物力学性能。本研究纳入了12例计划接受PAO手术的单侧发育性髋关节发育不良（DDH）患者（平均年龄27.81±4.64岁，42%为男性）。利用他们术前的CT图像以及术前和术后的步态数据创建特定于个体的肌肉骨骼模型，并完成逆动力学分析（IDA）。通过聚类分析选取两名具有典型步态特征的患者，并将他们的IDA数据纳入IS和TS固定的有限元（FE）模型。通过施加逐渐增加的步态负荷的迭代步骤进行失效模拟，以预测屈服载荷。在步态周期的不同阶段计算每个FE模型的应力结果和屈服载荷。与术前步态相比，术后步态有所改善，但仍逊于健康个体。术后步态的特点是髋关节活动范围较小，髂骨周围肌肉力量较低，尤其是外展肌，并且髋关节反应力（HRF）的初始峰值更尖锐，第二个峰值更平缓。有限元分析（FEA）显示在步态周期的第二至第四阶段应力有增加趋势，其他阶段应力水平较低。在高应力步态阶段，IS和TS之间以及耦合和非耦合肌肉力量之间的最大平均应力差异显著（P<0.05）。失效分析预测TS构型的屈服载荷（6.21体重）略大于IS（6.16体重），但两者均远高于步态负荷。耦合组和非耦合组结果相似，但非耦合组的屈服载荷较低（5.9*体重）。PAO术后早期步态呈正常化趋势，但异常情况仍然存在。IS和TS都能够抵抗机械应变失效，在PAO术后早期步态中未发现横向螺钉固定具有明显的机械优势。此外，需要注意的是，由于局部应力集中更大，TS可能具有更高的循环疲劳失效风险。此外，最内侧的螺钉对骨盆稳定性至关重要。
