Background

Percutaneous osseointegrated (OI) docking of prosthetic limbs returns loading directly to the residual bone of individuals with amputations. Lower limb diaphyseal biomechanics have not been studied during the wide range of daily activities performed by individuals with lower extremity amputations; therefore, little is known about the loads experienced at the bone-endoprosthetic interface of a percutaneous OI device.

Research question

Does residual limb length and/or gender influence loading magnitudes in the diaphysis of the femur or tibia during daily activities?

Methods

This observational study used motion capture data from 40 non-amputee volunteers performing nine activities ranging from low to high demand, to virtually simulate residual limbs of amputees. To simulate diaphyseal bone loading in individuals with lower limb amputations, virtual joints were defined during post-processing at 25, 50, and 75 % of residual limb length of both the femur and the tibia, representing six clinically relevant residual limb lengths for OI device placement. Peak axial distractive and compressive forces, torsional moments, and bending moments were calculated for each activity. Comparisons were made between genders and between different levels of the simulated residual limb.

Results

For simulated above and below knee amputations, short residual limbs showed the highest average bending, torsion, and axial distractive loads, while axial compressive loads were highest for long residual limbs. Absolute maxima for all subjects showed this same trend, except in below knee torsion, where 75 % residual tibia length showed the maximum. The highest demand activities yielding peaks in all directions were cutting with right leg planted, jump, run, and fall.

Significance

Overall, individuals with shorter residual limbs experienced higher diaphyseal forces. This should be taken into consideration during surgical implantation of percutaneous OI devices where residual limb length can potentially be shortened, and during rehabilitation of percutaneous OI patients.

中文翻译：

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下肢截肢者骨整合内置假体所经历的估计力和力矩。

背景

假肢的经皮骨整合 (OI) 对接将负载直接返回到截肢者的残余骨上。在下肢截肢患者进行的各种日常活动中，尚未研究下肢骨干生物力学；因此，对经皮 OI 装置的骨-内假体界面所承受的负荷知之甚少。

研究问题

在日常活动中，残肢长度和/或性别是否会影响股骨或胫骨骨干的负荷大小？

方法

这项观察性研究使用了 40 名非截肢志愿者的动作捕捉数据，他们进行了从低到高的九项活动，以虚拟模拟截肢者的残肢。为了模拟下肢截肢患者的骨干负荷，在后处理过程中定义了股骨和胫骨残肢长度的 25%、50% 和 75% 的虚拟关节，代表 OI 装置的六个临床相关残肢长度放置。计算每个活动的峰值轴向牵引力和压缩力、扭矩和弯矩。在性别之间和模拟残肢的不同水平之间进行比较。

结果

对于模拟的膝上和膝下截肢，短残肢显示出最高的平均弯曲、扭转和轴向分散载荷，而长残肢的轴向压缩载荷最高。所有受试者的绝对最大值都显示出相同的趋势，除了膝盖以下扭转，其中 75% 的残余胫骨长度显示最大值。在各个方向产生峰值的最高需求活动是右腿着地、跳跃、奔跑和摔倒。

意义

总体而言，残肢较短的个体经历了更高的骨干力。在残肢长度可能缩短的经皮 OI 装置的手术植入期间以及经皮 OI 患者的康复期间，应考虑到这一点。