Mini-Open Fifth Metatarsal Osteotomy with Intramedullary Rigid Fixation for Symptomatic Coughlin Type II and III Bunionette Deformity

Background: Bunionette deformity is commonly treated with distal or diaphyseal osteotomy, but concerns remain regarding correction loss, implant irritation, and metatarsal shortening. This study evaluated outcomes of mini-open fifth metatarsal osteotomy stabilized with intramedullary rigid fixation in symptomatic Coughlin type II and III deformity. Methods: This single-center retrospective observational study included 32 consecutive patients treated between February 2018 and February 2023. Radiographic outcomes included the fourth-to-fifth intermetatarsal angle (IMA), fifth metatarsophalangeal angle (MPA), maintenance of correction, and fifth metatarsal shortening. Clinical outcomes included the American Orthopaedic Foot and Ankle Society (AOFAS) score, visual analog scale (VAS) pain score, and complications. An exploratory subgroup analysis compared isolated correction with combined procedures. Results: The mean follow-up was 31.5 ± 6.8 months. The mean AOFAS score improved from 52.5 ± 4.2 to 93.4 ± 3.4, and the mean VAS score decreased from 7.8 ± 0.9 to 1.2 ± 0.6 (both p < 0.001). The mean MPA improved from 19.4° ± 3.6° to 2.3° ± 1.1°, and the mean IMA improved from 14.0° ± 1.4° to 4.5° ± 2.5° (both p < 0.001). Minor but statistically significant correction loss occurred between early postoperative and final follow-up radiographs. Mean fifth metatarsal shortening was 1.3 ± 0.8 mm. One patient required implant removal for hardware irritation. No nonunion, transfer metatarsalgia, or wound complications were observed. Conclusions: Mini-open fifth metatarsal osteotomy with intramedullary rigid fixation was associated with pain relief, functional improvement, maintained radiographic correction, limited shortening, and a low observed complication rate in this series.