Background

Kinematic and kinetic foot models showed that computing ankle joint angles, moments and power with a one-segment foot modeling approach alters kinematics and tends to overestimate ankle joint power. Nevertheless, gait studies continue to implement one-segment foot models to assess the effect of total ankle replacement.

Research question

The objective of this pilot study was to investigate the effect of the foot modeling approach (one-segment versus multi-segment) on how total ankle replacement is estimated to benefit or degrade the patient’s biomechanical performance.

Methods

Ten subjects with post-traumatic ankle osteoarthritis scheduled for total ankle replacement and 10 asymptomatic subjects were recruited. A one-segment and a multi-segment foot model were used to calculate intrinsic foot joints kinematics and kinetics during gait. A linear mixed model was used to investigate the effect of the foot model on ankle joint kinematic and kinetic analysis and the effect of total ankle replacement.

Results

Differences in range of motion due to the foot model effect were significant for all the gait subphases of interest except for midstance. Peak power generation was significantly overestimated when computed with the one-segment foot model. Ankle and shank-calcaneus joint dorsi-/plantarflexion range of motion did not increase post-operatively except during the loading response phase. A significant ‘group’ effect was found for stance and pre-swing phase range of motion, with total ankle replacement patients showing lower range of motion values than controls for dorsi/plantarflexion.

Significance

The outcome of this study showed that the ‘foot model’ had a significant effect on estimates of range of motion and power generation. The findings in our study therefore emphasize the clinical interest of multi-segment foot modeling when assessing the outcome of a therapeutic intervention.

中文翻译：

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足部建模对全踝置换效果量化的影响：一项初步研究

背景

运动学和动力学脚模型表明，使用单段脚模型方法计算踝关节角度，力矩和力量会改变运动学，并倾向于高估踝关节力量。尽管如此，步态研究继续采用单段脚模型来评估全踝置换的效果。

研究问题

这项初步研究的目的是研究足部建模方法（单段与多段）对如何估计全踝置换有益或降低患者生物力学性能的影响。

方法

招募了十名创伤后脚踝骨关节炎，计划进行全踝置换，并招募了十名无症状受试者。单段和多段脚模型用于计算步态中固有的脚关节运动学和动力学。使用线性混合模型研究足部模型对踝关节运动学和动力学分析的影响以及全踝关节置换的影响。

结果

由于足部模型效应，运动范围的差异对于所有感兴趣的步态亚相均很重要，除了中间步态。用单段脚模型计算时，峰值发电量被大大高估了。踝关节和小腿跟骨关节背屈/足底屈曲的运动范围除了在负荷反应阶段外没有增加。在站立和摆动前阶段的运动范围内发现了显着的“群体”效应，总踝关节置换患者的运动值范围比背部/足底屈曲的对照组低。

意义

这项研究的结果表明，“足部模型”对运动范围和发电量的估计有显着影响。因此，在我们的研究中，评估评估治疗干预的结果时，强调了多节段足部建模的临床意义。