Dynamic medial column stabilization using flexor hallucis longus tendon transfer in the surgical reconstruction of flatfoot deformity in adults

•Oftentimes, there are multiple locations of collapse within the medial column in the flatfoot deformity.•Dynamic medial column stabilization (DMCS) using flexor hallucis longus tendon transfer to the first metatarsal base is introduced.•The flatfoot reconstruction with DMCS restored the medial arch and corrected three planar deformities.