Department of Kinesiology, Université Laval, 2325, rue de l'Université, Québec, QC, G1V 0A6, Canada; Centre for Interdisciplinary Research in Rehabilitation and Social Integration (CIRRIS), 525, boul. Wilfrid-Hamel, Québec, QC, G1M 2S8, Canada.
CHU de Québec-Université Laval, 11, côte du Palais, Québec, QC, G1R 2J6, Canada.
Gait Posture. 2021 Jan;83:237-244. doi: 10.1016/j.gaitpost.2020.11.001. Epub 2020 Nov 6.
Posterior tibial tendon dysfunction (PTTD) is characterized by degeneration of this tendon leading to a flattening of the medial longitudinal arch of the foot. Foot orthoses (FOs) can be used as a treatment option, but their biomechanical effects on individuals with PTTD are not yet fully understood.
The aim of this study was to investigate the effects of three types of FOs on gait biomechanics in individuals with PTTD.
Fourteen individuals were recruited with painful stage 1 or 2 PTTD based on Johnson and Strom's classification. Quantitative gait analysis of the affected limb was performed in four conditions: shoes only (Shoe), prefabricated FO (PFO), neutral custom FO (CFO) and custom varus FO (CVFO) with a 5° medial wedge and a 4 mm medial heel skive. A curve analysis, using 1D statistical parametric mapping, was undertaken to assess differences in lower limb joint motion, joint moments and muscle activity over the stance phase of gait across conditions.
Decreased hindfoot eversion angles, decreased ankle inversion moments and increased ankle eversion moments were observed with custom FOs compared to the Shoe and PFO conditions (p < 0.001). CFOs and CVFOs induced an increased knee abduction moment compared to Shoe (p < 0.001). No changes in hip kinematics and kinetics or in EMG activity of tested muscles were observed between conditions.
Custom orthoses may be more suitable than PFOs to decrease the pathological biomechanical outcomes observed in PTTD. Decreased ankle inversion moments during the stance phase could explain why custom orthoses are effective at reducing pain in PTTD patients. However, clinicians should be careful when prescribing custom orthoses for PTTD since unwanted collateral biomechanical effects can be observed at the knee.
胫骨后肌腱功能障碍（PTTD）的特征是该肌腱退化，导致足内侧纵弓变平。足部矫形器（FO）可用作治疗选择，但它们对 PTTD 患者的生物力学影响尚不完全清楚。
本研究旨在探讨三种 FO 对 PTTD 患者步态生物力学的影响。
根据 Johnson 和 Strom 的分类，招募了 14 名患有疼痛性 1 期或 2 期 PTTD 的患者。对患侧肢体进行了定量步态分析，共 4 种情况：仅穿鞋（Shoe）、预制 FO（PFO）、中性定制 FO（CFO）和定制内翻 FO（CVFO），内侧楔 5°，内侧跟骨削 4mm。使用 1D 统计参数映射进行曲线分析，以评估在步态站立阶段各条件下下肢关节运动、关节力矩和肌肉活动的差异。
与 Shoe 和 PFO 相比，定制 FO 可使足跟外翻角度减小，踝关节内翻力矩减小，踝关节外翻力矩增大（p<0.001）。与 Shoe 相比，CFO 和 CVFO 会引起膝关节外展力矩增加（p<0.001）。各条件下髋关节运动学和动力学或测试肌肉的肌电图活动无变化。
与 PFO 相比，定制 FO 可能更适合降低在 PTTD 中观察到的病理性生物力学结果。站立阶段踝关节内翻力矩减小可能解释了为什么定制 FO 可有效减轻 PTTD 患者的疼痛。然而，由于可能会出现膝关节的意外代偿生物力学效应，因此在为 PTTD 患者开具定制 FO 时，临床医生应小心谨慎。
