Publication:

Effects of extraosseous talotarsal stabilization on the biomechanics of flexible flatfoot subtalar joints in children: a finite element study

Background Objective of the study was to generate an experimental foundation for the clinical application of extraosseous talotarsal stabilization (EOTTS) in treatment of flexible flatfeet in children by investigating the biomechanical characteristics of flexible flatfoot and the effects of EOTTS on hindfoot biomechanics.

Methods Three-dimensional finite element models of the foot and ankle complex were generated from computer tomography images of a volunteer’s left foot in three states: normal, flexible flatfoot, and post-EOTTS. After validation by X-ray, simulated loads were applied to the three models in a neutral position with both feet standing.

Results In the flexible flatfoot model, the contact stress on the subtalar joint increased and contact areas decreased, resulting in abnormal stress distribution compared to the normal model. However, following treatment of the foot with EOTTS, these parameters returned to close to normal. Subtalar joint instability leads to a flexible flat foot. Based on this study, it is proposed that EOTTS can restore the normal function of the subtalar joint in and is an effective treatment for flexible flatfoot in children. We and many clinical data studies provide evidence for sinus tarsi implants in pediatric patients. It is showed that the formation of flexible flatfoot is induced by subtalar joint instability.

Conclusions Because of the EOTTS provides the best biomechanical solution to subtalar joint instability, the EOTTS became an effective form for subtalar joint instability treatment.