ObjectiveTo explore the effectiveness and operative methods to treat first metatarsal diaphysis comminuted fractures with mini-plate via medial approach. MethodsBetween January 2012 and January 2013, 15 patients with first metatarsal shaft comminuted fractures were treated. There were 11 males and 4 females (6 left feet and 9 right feet) with an average age of 38.6 years (range, 27-56 years). The injury causes included falling injury in 6 cases, crash injury of heavy object in 7 cases, and sprain in 2 cases. The left side was involved in 6 cases and the right side in 9 cases. The time from injury to operation was 8.5 days on average (range, 7-10 days). According to AO classification, all cases were rated as 81(T)-C2 type. The surgical treatments included open reduction and internal fixation with mini-plate by medial approach. ResultsPrimary healing of incision was obtained in all cases, and no infection occurred. Twelve patients were followed up 18 months on average (range, 12-24 months). All fractures healed well, and the mean time of bone union was 11.5 weeks (range, 10-14 weeks). No loosening or breakage of internal fixation was observed. At last follow-up, the patients could walk with full weight-bearing, and had no pain. According to American Orthopaedic Foot and Ankle Society (AOFAS) hallux metatarsophalangeal-interphalangeal scale, the mean score was 85.2 (range, 76-96). ConclusionAnatomic reduction and stable internal fixation are important for first metatarsal comminuted fracture, which is the key point for recovery of foot form and foot arch function. And the medial approach could achieve full exposure and improve the cosmetic results.