Program in Physical Therapy, Washington University School of Medicine, St. Louis, MO, USA.
Department of Mechanical Engineering, University of Colorado-Denver, Denver, CO, USA.
J Biomech. 2022 Apr;135:111023. doi: 10.1016/j.jbiomech.2022.111023. Epub 2022 Feb 28.
Developmental dysplasia of the hip (DDH) causes hip instability and early-onset osteoarthritis. The focus on pathomechanics in DDH has centered on the shallow acetabulum, however there is growing awareness of the role of femoral deformities in joint damage. The objective of this study was to determine the influence of femoral version (FV) on the muscle and joint reaction forces (JRFs) of dysplastic hips during gait. Magnetic resonance images, in-vivo gait data, and musculoskeletal models were used to calculate JRFs and simulate changes due to varying FV deformities. Rotation about the long axis of the femur was added in the musculoskeletal models to simulate FV values from -5° (relative retroversion) to + 35° (increased anteversion). In our simulations, FV deformities caused the largest changes to the anteroposterior and resultant JRFs. From a normal FV of 15°, a 15° increase in femoral anteversion caused JRFs to be less posterior in early stance (Δ = 0.43 ± 0.22 xbodyweight) and more anterior in late stance (Δ = 0.60 ± 14 xbodyweight). Relative retroversion caused anteroposterior changes that were similar to anteversion in early stance but opposite in late stance. Resultant JRFs experienced the largest changes during late stance where anteversion raised the peak by 0.48 ± 0.15 xbodyweight and relative retroversion lowered the peak by 0.32 ± 0.30 xbodyweight. Increasing anteversion increased hip flexor and abductor muscle forces, which caused the changes in JRFs. Identifying how FV deformities influence hip joint loading can elucidate their role in the mechanisms of hip degeneration in patients with DDH.
髋关节发育不良（DDH）导致髋关节不稳定和早发性骨关节炎。DDH 的病理力学研究重点一直集中在髋臼浅，然而，人们越来越意识到股骨畸形在关节损伤中的作用。本研究的目的是确定股骨前倾角（FV）在步态中对发育性髋关节肌肉和关节反作用力（JRFs）的影响。使用磁共振成像、体内步态数据和肌肉骨骼模型来计算 JRFs 并模拟由于 FV 变形而导致的变化。在肌肉骨骼模型中增加了股骨长轴的旋转，以模拟从-5°（相对后旋）到+35°（增加前旋）的 FV 值。在我们的模拟中，FV 畸形导致前后向和合成 JRF 发生最大变化。从正常 FV 15°开始，股骨前旋增加 15°会导致早期站立时 JRF 更向后（Δ=0.43±0.22 x体重），晚期站立时更向前（Δ=0.60±14 x体重）。相对后旋引起的前后向变化与早期站立时的前旋相似，但晚期站立时相反。合成 JRF 在晚期站立时经历了最大的变化，其中前旋使峰值增加了 0.48±0.15 x体重，相对后旋使峰值降低了 0.32±0.30 x体重。增加前旋会增加髋关节屈肌和外展肌的力量，从而导致 JRF 发生变化。确定 FV 畸形如何影响髋关节负荷可以阐明其在 DDH 患者髋关节退变机制中的作用。
