Fröberg Åsa, Mårtensson Mattias, Arndt Anton
Division of Orthopaedics and Biotechnology, Department of Clinical Sciences, Intervention and Technology (Clintec), Karolinska Institute, Stockholm, Sweden.
KTH, Biomedical Engineering and Health Systems, Stockholm, Sweden.
Front Sports Act Living. 2020 Mar 17;2:16. doi: 10.3389/fspor.2020.00016. eCollection 2020.
Following an Achilles tendon rupture, ankle foot orthoses (AFO) of different designs are used to protect the healing tendon. They are generally designed to protect against re-rupture by preventing undesired dorsiflexion and to prevent elongation by achieving plantarflexion in the ankle. There is limited knowledge of the biomechanical effects of different AFO designs and ankle angles on the tendon and lower leg muscles. The hypothesis was that non-uniform displacement in the Achilles tendon, lower leg muscle activity, and plantar pressure distribution would be affected differently in different designs of AFO and by varying the degree of dorsiflexion limitation. Controlled laboratory study. Ultrasound of the Achilles tendon, EMG of the lower leg muscles and plantar pressure distribution were recorded in 16 healthy subjects during walking on a treadmill unbraced and wearing three designs of AFO. Ultrasound speckle tracking was used to estimate motion within the tendon. The tested AFO designs were a rigid AFO and a dorsal brace used together with wedges and an AFO with an adjustable ankle angle restricting dorsiflexion to various degrees. There were no significant differences in non-uniform tendon displacement or muscle activity between the different designs of AFO. For the rigid AFO and the adjustable AFO there was a significant reduction in non-uniform displacement within the tendon and soleus muscle activity as restriction in dorsiflexion increased. The degree of dorsiflexion allowed within an AFO had greater effects on Achilles tendon displacement patterns and muscle activity in the calf than differences in AFO design. AFO settings that allowed ankle dorsiflexion to neutral resulted in displacement patterns in the Achilles tendon and muscle activity in the lower leg which were close to those observed during unbraced walking.
跟腱断裂后，会使用不同设计的踝足矫形器（AFO）来保护愈合中的肌腱。它们通常旨在通过防止不必要的背屈来防止再次断裂，并通过实现踝关节跖屈来防止肌腱伸长。关于不同AFO设计和踝关节角度对肌腱及小腿肌肉的生物力学影响，人们了解有限。假设是，跟腱的非均匀位移、小腿肌肉活动和足底压力分布在不同设计的AFO以及通过改变背屈限制程度时会受到不同影响。对照实验室研究。在16名健康受试者于跑步机上无支撑行走以及佩戴三种设计的AFO行走时，记录跟腱超声、小腿肌肉肌电图和足底压力分布。使用超声散斑跟踪来估计肌腱内的运动。测试的AFO设计包括一种刚性AFO、一种与楔形物一起使用的背侧支具以及一种踝关节角度可调节且将背屈限制在不同程度的AFO。不同设计的AFO在肌腱非均匀位移或肌肉活动方面无显著差异。对于刚性AFO和可调节AFO，随着背屈限制增加，肌腱内的非均匀位移和比目鱼肌活动显著减少。AFO内允许的背屈程度对跟腱位移模式和小腿肌肉活动的影响大于AFO设计差异。允许踝关节背屈至中立位的AFO设置导致跟腱位移模式和小腿肌肉活动与无支撑行走时观察到的情况相近。
