Department of Mechanical Engineering, Stanford University, 318 Campus Drive, Stanford, CA 94305, USA.
Department of Bioengineering, Stanford University, 318 Campus Drive, Stanford, CA 94305, USA.
Gait Posture. 2023 Jan;99:1-8. doi: 10.1016/j.gaitpost.2022.10.010. Epub 2022 Oct 18.
Spina bifida, a neurological defect, can result in lower-limb muscle weakness. Altered ambulation and reduced musculoskeletal loading can yield decreased bone strength in individuals with spina bifida, yet individuals who remain ambulatory can exhibit normal bone outcomes.
During walking, how do lower-limb joint kinematics and moments and tibial forces in independently ambulatory children with spina bifida differ from those of children with typical development?
We retrospectively analyzed data from 16 independently ambulatory children with spina bifida and 16 children with typical development and confirmed that tibial bone strength was similar between the two groups. Plantar flexor muscle strength was measured by manual muscle testing, and 14 of the children with spina bifida wore activity monitors for an average of 5 days. We estimated tibial forces at the knee and ankle using motion capture data and musculoskeletal simulations. We used Statistical Parametric Mapping t-tests to compare lower-limb joint kinematic and kinetic waveforms between the groups with spina bifida and typical development. Within the group with spina bifida, we examined relationships between plantar flexor muscle strength and peak tibial forces by calculating Spearman correlations.
Activity monitors from the children with spina bifida reported typical daily steps (9656 [SD 3095]). Despite slower walking speeds (p = 0.004) and altered lower-body kinematics (p < 0.001), children with spina bifida had knee and ankle joint moments and forces similar to those of children with typical development, with no detectable differences during stance. Plantar flexor muscle weakness was associated with increased compressive knee force (p = 0.002) and shear ankle force (p = 0.009).
High-functioning, independently ambulatory children with spina bifida exhibited near-typical tibial bone strength and near-typical step counts and tibial load magnitudes. Our results suggest that the tibial forces in this group are of sufficient magnitudes to support the development of normal tibial bone strength.
神经管缺陷会导致下肢肌肉无力。运动方式改变和肌肉骨骼负荷减少会导致脊柱裂患者的骨强度降低，但仍能行走的患者可能会表现出正常的骨骼结果。
在行走过程中，自主行走的脊柱裂患儿的下肢关节运动学和力矩以及胫骨力与具有典型发育的儿童有何不同？
我们回顾性分析了 16 名自主行走的脊柱裂患儿和 16 名具有典型发育的儿童的数据，并确认两组儿童的胫骨骨强度相似。通过手动肌肉测试测量跖屈肌力量，14 名脊柱裂患儿平均佩戴活动监测器 5 天。我们使用运动捕捉数据和肌肉骨骼模拟来估计膝关节和踝关节的胫骨力。我们使用统计参数映射 t 检验比较了脊柱裂和典型发育两组的下肢关节运动学和运动学波形。在脊柱裂组内，我们通过计算 Spearman 相关系数来研究跖屈肌力量与峰值胫骨力之间的关系。
脊柱裂患儿的活动监测器报告了典型的日常步数（9656 [SD 3095]）。尽管行走速度较慢（p=0.004）且下肢运动学改变（p<0.001），但脊柱裂患儿的膝关节和踝关节力矩和力与具有典型发育的儿童相似，在站立阶段没有可检测到的差异。跖屈肌力量弱与膝关节压缩力增加（p=0.002）和踝关节剪切力增加（p=0.009）有关。
高功能、自主行走的脊柱裂患儿表现出接近典型的胫骨骨强度和接近典型的步数计数以及胫骨负荷大小。我们的结果表明，该组的胫骨力足以支持正常胫骨骨强度的发展。
