INTRODUCTION: Comminuted fractures involving the articular surface of the base of the proximal phalanx are relatively rare. We treated a patient with this type of fracture by open reduction and internal fixation with a locked-wire-type external fixator (Ichi-Fixator System). PRESENTATION OF CASE: A 45-year-old man was injured because his ring finger was kicked during a Futsal game. Radiographs and computed tomography revealed a comminuted intraarticular fracture of the proximal phalanx of this ring finger. We treated the fracture with open reduction and K-wires and external fixation. We removed the K-wire and external fixator 5 weeks postoperatively and initiated range of motion exercises. Five months postoperatively, his finger motion was fully recovered without restriction. DISCUSSION: Comminuted intraarticular fractures of the base of the proximal phalanx are usually treated with plating. Complications such as interference with excursion of the central slip and lateral bands, extensor tendon rupture, and plate prominence have been reported in these fractures. In our patient, the Ichi-Fixator System was useful as a distraction apparatus for metacarpophalangeal joint fixation. CONCLUSION: A comminuted intra-articular fracture of the base of the proximal phalanx was treated successfully using the Ichi-Fixator system.