Frossard Laurent, Cheze Laurence, Dumas Raphael
Group of Research on Adapted Physical Activities, University of Quebec, Montreal, Canada.
Prosthet Orthot Int. 2011 Jun;35(2):140-9. doi: 10.1177/0309364611409002.
Calculation of lower limb kinetics is limited by floor-mounted force-plates.
Comparison of hip joint moments, power and mechanical work on the prosthetic limb of a transfemoral amputee calculated by inverse dynamics using either the ground reactions (force-plates) or knee reactions (transducer).
Comparative analysis.
Kinematics, ground reaction and knee reaction data were collected using a motion analysis system, two force-plates, and a multi-axial transducer mounted below the socket, respectively.
The inverse dynamics using ground reaction underestimated the peaks of hip energy generation and absorption occurring at 63% and 76% of the gait cycle (GC) by 28% and 54%, respectively. This method also overestimated by 24% a phase of negative work at the hip (37%-56% GC), and underestimated the phases of positive (57%-72% GC) and negative (73%-98%GC) work at the hip by 11% and 58%, respectively.
A transducer mounted within the prosthesis has the capacity to provide more realistic kinetics of the prosthetic limb because it enables assessment of multiple consecutive steps and a wide range of activities without the issue of foot placement on force-plates.
The hip is the only joint an amputee controls directly to set the prosthesis in motion. Hip joint kinetics are associated with joint degeneration, low back pain, risk of falls, etc. Therefore, realistic assessment of hip kinetics over multiple gait cycles and a wide range of activities is essential.
下肢动力学的计算受限于地面安装的测力台。
比较通过逆动力学分别使用地面反作用力（测力台）或膝关节反作用力（传感器）计算的经股骨截肢者假肢髋关节力矩、功率和机械功。
对比分析。
分别使用运动分析系统、两个测力台和安装在接受腔下方的多轴传感器收集运动学、地面反作用力和膝关节反作用力数据。
使用地面反作用力的逆动力学分别低估了在步态周期（GC）的63%和76%时出现的髋关节能量产生和吸收峰值的28%和54%。该方法还高估了髋关节负功阶段（37%-56%GC）24%，并分别低估了髋关节正功阶段（57%-72%GC）和负功阶段（73%-98%GC）11%和58%。
安装在假肢内的传感器能够提供更真实的假肢动力学，因为它能够评估多个连续步骤和广泛的活动，而不存在脚放置在测力台上的问题。
髋关节是截肢者直接控制以启动假肢运动的唯一关节。髋关节动力学与关节退变、腰痛、跌倒风险等相关。因此，在多个步态周期和广泛活动中对髋关节动力学进行真实评估至关重要。
