Sinus tarsi: a proprioceptive organ?

Abstract

Background Flexible flatfoot in children is one of the most common disorders in orthopedics. The mechanism of action of the subtalar implants used for correction of the deformity is still unclear. Purpose The aim of this study was to identify the neurohistological nature of the subtalar tissues in an attempt to clarify the mechanism of action of sinus tarsi implants used for correction of flexible flatfeet. Patients and methods From 46 patients (mean age 39 year, 26 male and 20 female), soft tissue material was excised from the sinus tarsi during operative intervention in the foot for different indications. The excised tissues were studied histologically with different staining methods. Results The histological examination revealed the presence of large amount of neural elements (mechanoreceptors) together with abundant elastic fibers in all of the excised subtalar tissues. Conclusion Our findings suggest that the sinus tarsi is a neurosensitive elastic organ and has a proprioceptive information mechanism. This may be of great value in the treatment of patients with flexible flatfeet using subtalar implants.