Background

Subtalar arthroereisis may cause sinus tarsi pain complications. In this study, we aimed to introduce a customized implant that facilitated treatment effect and less impingement. The biomechanical outcome between the intact and implant conditions was compared using finite element analysis.

Methods

A female patient with flatfoot (age: 36 years, height: 156 ​cm, body mass: 51 ​kg) was recruited as the model patient. The customized implant was designed from the extracted geometry. Boundary and loading conditions were assumed from the data of a normal participant. Four gait instants, including the ground reaction force first peak (25% stance), valley (45%), initial push-off (60%) and second peak (75%) were analyzed.

Results

The navicular height was elevated by 4.2% at 25% stance, whereas the strain of the spring, plantar cuneonavicular and plantar cuboideonavicular ligaments were reduced. The talonavicular joint force decreased and the calcaneocuboid joint increased by half and 67%, respectively, representing a lateralized load pathway. There was a stress concentration at the sulcus tali reaching 15.29 ​MPa

Conclusion

Subtalar arthroereisis using a customized implant may produce some positive treatment effects in terms of navicular height elevation, ligament strain relief and lateralized joint loading pathway. Although the concentrated stress at the sulcus tali did not exceed the threshold of bone breakdown, we could not rule out the potential of vascular disturbance owing to the remarkable elevation of stress. Future study may enlarge the contact area of the bone–implant interface by considering customization based on the dynamic change of the sinus tarsi during walking gait.

The translational potential of this article

Geometry mismatch of prefabricated implants could be the reason for complications. With the advancement of 3D printing, customizing implant becomes possible and may improve treatment outcome. This study implemented a theoretical model approach to explore its potential under a simulation of walking.

中文翻译：

---

使用定制跗骨窦植入物对成人获得性扁平足畸形的距下关节关节固定术的有限元分析

背景

距下关节止痛可能引起跗骨窦疼痛并发症。在这项研究中，我们旨在介绍一种定制的植入物，该植入物有助于提高治疗效果并减少撞击。使用有限元分析比较完整和植入条件之间的生物力学结果。

方法

招募一名女性扁平足患者（年龄：36岁，身高：156cm，体重：51kg）作为模型患者。定制的植入物是根据提取的几何形状设计的。根据正常参与者的数据假设边界和加载条件。分析了四个步态瞬间，包括地面反作用力第一个峰值（25% 站立）、谷值（45%）、初始推离（60%）和第二个峰值（75%）。

结果

在 25% 站姿时，舟骨高度提高了 4.2%，而弹簧、足底楔舟韧带和足底立方舟韧带的应变降低。距舟关节力下降，跟骰关节分别增加一半和 67%，代表侧向载荷路径。大里沟应力集中达到 15.29 MPa

结论

使用定制植入物的距下关节滑脱术可能会在舟骨高度升高、韧带应变缓解和侧向关节负荷通路方面产生一些积极的治疗效果。尽管距骨沟处的集中应力没有超过骨破坏的阈值，但由于应力的显着升高，我们不能排除血管紊乱的可能性。未来的研究可能会通过考虑基于行走步态期间跗骨窦动态变化的定制来扩大骨-植入物界面的接触面积。

本文的翻译潜力

预制植入物的几何形状不匹配可能是并发症的原因。随着 3D 打印技术的进步，定制植入物成为可能，并可能改善治疗效果。本研究实施了一种理论模型方法来探索其在步行模拟下的潜力。