Loading Effect of Prosthetic Feet's Anthropomorphicity on Transtibial Osseointegrated Implant.
Loading Effect of Prosthetic Feet's Anthropomorphicity on Transtibial Osseointegrated Implant.
复制标题
假足拟人化对小腿骨整合植入物的负载效应。
DOI：
10.1093/milmed/usaa461
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发表时间：
2021
影响因子：
1.2
通讯作者：
Frossard,Laurent
中科院分区：
文献类型：
--
作者：
Pitkin,Mark;Frossard,Laurent
前言骨整合种植体经胫骨假体的直接骨性附着体具有尚未完全解决的风险，如早期松动、假体的经皮和髓部机械失效、假体周围问题和感染。过载可能会导致早期松动和感染。超负荷可能会损害骨-种植体界面。因此，在康复期间及以后，经胫骨锚定假体所应用的金发锁负荷方案对于种植体周围骨结合的安全和有效的发展至关重要。我们假设，当一个所谓的拟人假肢行走时，可以实现金发负荷，其力矩-角度关系类似于健全的脚踝。材料和方法提取4名健康受试者自由步态步行背屈阶段健全的踝力矩-角度曲线的量化特征(实验1)。计算了力矩-角度曲线的斜率(刚度)两次：对于力矩-角度曲线的前半部分和后半部分。硬度之差(后半部分减去前半部分)称为拟人性指数(IA)。根据定义，正IA与力矩-角曲线的凹形相关联，负IA与凸形相关联。在实验2中，对3名安装了经胫骨集成固定器的参与者进行了相同的记录和计算，分别用他们平常的脚和自由流动的脚(Ohio Willow Wood)行走。结果健全受试者的IA为5.88 ± 0.93，表明背屈阶段第一阶段的僵硬程度明显低于第二阶段，因为小腿肌肉抵抗踝关节角度的能力明显低于背屈阶段第二阶段。正常足截肢者IA为2.6 8 ± 1.0 9，正常足截肢者IA为2.97 ± 2.37。结论健全组和自由流足截肢者的拟人性指标均为正值，且与弯矩-角度曲线凹陷程度有关。受试者通常穿的3只脚被归类为非拟人化，因为他们各自的力矩-角度曲线是凸形的，对应的IAS是负的。此外，这项研究表明，与非拟人化的脚相比，具有拟人化特征的脚倾向于降低骨-种植体界面的最大载荷，并可能将损害该界面完整性的风险降至最低。
IntroductionOsseointegrated implants for direct skeletal attachment of transtibial prosthesis carry risks that are yet to be fully resolved, such as early loosening, mechanical failure of percutaneous and medullar parts of implant, periprosthetic issues, and infections. Underloading could lead to early loosening and infection. Overloading might compromise the bone–implant interface. Therefore, Goldilocks loading regimen applied by transtibial bone-anchored prostheses is critical for safe and efficient development of osseointegration around the implant during rehabilitation and beyond. We hypothesized that Goldilocks loading could be achieved when ambulating with a so-called anthropomorphic prosthetic ankle showing moment–angle relationship similar to a sound ankle.Materials and MethodsQuantitative characteristics of the moment–angle curve of the sound ankle during dorsiflexion phase of a free-pace walking were extracted for 4 able-bodied participants (experiment 1). A slope of the moment–angle curve (stiffness) was calculated twice: for the first half and for the second half of the moment–angle curve. The difference of stiffnesses (those at the second half minus at the first half) was called the index of anthropomorphicity (IA). By definition, positive IA is associated with concave shape of the moment–angle curve, and the negative IA is associated with convex shape. In experiment 2, the same recordings and calculations were performed for 3 participants fitted with transtibial osseointegrated fixation during walking with their usual feet and the Free-Flow Foot (Ohio Willow Wood). The Free-Flow Foot was selected for its anthropomorphicity demonstrated in the previous studies with amputees using traditional socket attachment.ResultsThe IA was 5.88 ± 0.93 for the able-bodied participants, indicating that the stiffness during the first part of the dorsiflexion phase was substantially fewer than during the second parts, as the calf muscles resisted to angulation in ankle substantially less than during the second part of dorsiflexion phase. For amputees fitted with Free-Flow Foot, IA was 2.68 ± 1.09 and −2.97 ± 2.37 for the same amputees fitted with their usual feet.ConclusionsIndexes of anthropomorphicity, while of different magnitude, were positive in control able-bodied group and in the amputee group wearing Free-Flow Foot, which was qualitatively associated with concave shape of their moment–angle curves. The 3 usual feet worn by the participants were classified as nonanthropomorphic as their individual moment–angle curves were convex and the corresponding IAs were negative. Furthermore, this study showed that a foot with anthropomorphic characteristics tends to decrease maximal loads at the bone–implant interface as compared to the nonanthropomorphic feet and possibly may minimize the risks to compromise the integrity of this interface.