Endosinotarsal vs. Exosinotarsal Subtalar Arthroereisis in Treating Pediatric Flexible Flat Feet

BACKGROUND: Pediatric flexible flatfoot (FFF) is a common condition characterized by the collapse of the medial longitudinal arch, which can lead to pain and functional impairment in a subset of patients. Subtalar arthroereisis (AR) is a minimally invasive procedure that corrects FFF by limiting excessive pronation of the subtalar joint. Two main techniques exist: endosinotarsal AR, which involves placing an implant in the sinus tarsi, and exosinotarsal AR, which uses a screw external to the sinus tarsi. This systematic review and meta-analysis compares the clinical outcomes and complication rates of these 2 techniques. METHODS: A comprehensive literature search was conducted in Scopus, Web of Science, and PubMed. Only comparative clinical studies comparing endosinotarsal and exosinotarsal AR in pediatric patients with FFF were included. RESULTS: A total of 6 studies involving 791 feet were analyzed. The exosinotarsal group showed a statistically significant improvement in talocalcaneal (Kite) angle (mean difference = -1.14; p = 0.04), although the difference may not be clinically significant. Calcaneal pitch angle analysis revealed no significant difference, but sensitivity analysis favored the exosinotarsal technique when 1 study was excluded (mean difference = -2.21; p = 0.004). Postoperative pain was reported with higher rates in the exosinotarsal group, as well as screw breakage, while the endosinotarsal group had higher rates of implant dislocation. CONCLUSION: Both techniques effectively treat pediatric FFF, but exosinotarsal AR may offer better structural correction. However, it may be associated with higher rates of pain that tend to recede after 6 months from the operation. LEVEL OF EVIDENCE: Level II. See Instructions for Authors for a complete description of levels of evidence.