Department of Mechanical Engineering, Colorado School of Mines, Golden, CO 80401, USA.
J Biomech. 2012 Aug 31;45(13):2271-8. doi: 10.1016/j.jbiomech.2012.06.008. Epub 2012 Jul 25.
Unilateral, below-knee amputees have altered gait mechanics, which can significantly affect their mobility. Below-knee amputees lose the functional use of the ankle muscles, which are critical during walking to provide body support, forward propulsion, leg-swing initiation and mediolateral balance. Thus, either muscles must compensate or the prosthesis must provide the functional tasks normally provided by the ankle muscles. Three-dimensional (3D) forward dynamics simulations of amputee and non-amputee walking were generated to identify muscle and prosthesis contributions to amputee walking mechanics, including the subtasks of body support, forward propulsion, leg-swing initiation and mediolateral balance. Results showed that the prosthesis provided body support in the absence of the ankle muscles. The prosthesis contributed to braking from early to mid-stance and propulsion in late stance. The prosthesis also functioned like the uniarticular soleus muscle by transferring energy from the residual leg to the trunk to provide trunk propulsion. The residual-leg vasti and rectus femoris reduced their contributions to braking in early stance, which mitigated braking from the prosthesis during this period. The prosthesis did not replace the function of the gastrocnemius, which normally generates energy to the leg to initiate swing. As a result, lower overall energy was delivered to the residual leg. The prosthesis also acted to accelerate the body laterally in the absence of the ankle muscles. These results provide further insight into muscle and prosthesis function in below-knee amputee walking and can help guide rehabilitation methods and device designs to improve amputee mobility.
单侧小腿截肢者的步态力学发生了改变，这会显著影响他们的移动能力。小腿截肢者丧失了踝关节肌肉的功能作用，而这些肌肉在行走时对于提供身体支撑、向前推进、启动腿部摆动以及维持身体的横向平衡至关重要。因此，要么需要肌肉来代偿，要么假肢需要提供通常由踝关节肌肉提供的功能任务。本研究通过对截肢者和非截肢者行走的三维（3D）前向动力学模拟，来确定肌肉和假肢对截肢者行走力学的贡献，包括身体支撑、向前推进、腿部摆动启动和横向平衡等子任务。结果表明，在没有踝关节肌肉的情况下，假肢提供了身体支撑。在早期支撑阶段，假肢起到了制动作用，而在晚期支撑阶段，假肢起到了推进作用。假肢还可以像单关节比目鱼肌一样，通过将能量从残肢传递到躯干，从而为躯干提供推进力。残肢股四头肌和股直肌减少了在早期支撑阶段的制动作用，从而减轻了假肢在这段时间内的制动作用。假肢并没有取代腓肠肌的功能，腓肠肌通常会为腿部摆动提供能量。因此，残肢接收到的能量总体上减少了。在没有踝关节肌肉的情况下，假肢还起到了使身体向侧面加速的作用。这些结果进一步深入了解了小腿截肢者行走时肌肉和假肢的功能，可以帮助指导康复方法和设备设计，以提高截肢者的移动能力。
