Effects of alignment changes on stance phase pressures and shear stresses on transtibial amputees: measurements from 13 transducer sites.
Effects of alignment changes on stance phase pressures and shear stresses on transtibial amputees: measurements from 13 transducer sites.
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DOI：
10.1109/86.662617
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发表时间：
1998-03-01
期刊：
影响因子：
--
通讯作者：
Dralle, A J
中科院分区：
文献类型：
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作者：
Sanders, J E;Bell, D M;Dralle, A J
对两名使用下肢髌腱支撑假肢行走的单侧膝下截肢者的 13 个部位测量了界面压力和剪切应力。在不同的套筒-柄对齐设置下，研究了柄轴向力-时间曲线中第一个峰值时的界面应力。压力的应力大小为 1.2 至 214.7 kPa，合成剪应力为 0.4 至 79.6 kPa，由于未对准而导致的应力变化为压力为 1.3 至 80.7 kPa，合成剪应力为 0.2 至 38.0 kPa。对于两名受试者，前窝区域的界面应力变化比外侧或后区域大得多。因此，排列变化对界面应力有局部影响。对于两个受试者来说，对准与压力或合成剪切应力的关系图都是非线性的，在许多情况下在标称对准处最大化或最小化，表明复杂的界面应力对准关系。标称步骤与未对准步骤的变化（标准差/平均值）没有显着差异，表明受试者很好地适应了对准变化。界面应力的会话间差异通常大于由对准修改引起的界面应力差异。因此，虽然这些受试者很好地补偿了对齐变化，以在训练中保持一致的界面压力，但他们在相隔数周进行的不同训练中却没有这样做。
Interface pressures and shear stresses were measured at 13 sites on two unilateral below-knee amputee subjects ambulating with lower-limb patellar-tendon-bearing prostheses. Interface stresses at the time of the first peak in the shank axial force-time curve were investigated at different socket-shank alignment settings. Stress magnitudes ranged from 1.2 to 214.7 kPa for pressure and 0.4 to 79.6 kPa for resultant shear stress, and changes in stress due to misalignment ranged from 1.3 to 80.7 kPa for pressure and from 0.2 to 38.0 kPa for resultant shear stress. For both subjects interface stress changes were much greater in the anterior socket region than in the lateral or posterior regions. Thus, alignment changes had a localized effect on interface stresses. Plots of alignment versus pressure or resultant shear stress were nonlinear for both subjects, in a number of cases maximizing or minimizing at the nominal alignment, indicating complex interface stress-alignment relationships. Variation (standard deviation/mean) was not significantly different for nominal versus misaligned steps, indicating that the subjects adapted well to the alignment changes. Session to session differences in interface stresses were typically larger than interface stress differences induced by alignment modifications. Thus, while these subjects compensated well for alignment changes to maintain consistent interface stresses within a session, they did not do so for different sessions conducted weeks apart.