Abstract We report herein a retrospective study of 25 cases of ankle arthrodesis performed in 23 patients with rheumatoid arthritis (RA) using an intramedullary nail with fins, developed in 1994. Surgical treatment, postoperative management, and clinical evaluation are described. Clinical evaluation, at an average follow-up period of 7 years 1 month, was based on foot disease scores from the Japanese Orthopedic Association; we compared these scores pre- and postoperatively, and during follow-up. These parameters showed a significant difference between preoperation and the follow-up period. However, instability only significantly improved when compared between pre- and postoperation. Arthrodesis using an intramedullary nail with fins was effective for the treatment of severe deformity of the hind foot. Nonunion was not observed and no remarkable changes of the Chopart joint were recognized between preoperation and the follow-up period. In our series, delayed wound healing was recognized in 6 of 25 joints. However, infection or neuropathy and other complications were not found. Arthrodesis using an intramedullary nail with fins is a viable treatment option for severe deformity of the hind foot in RA patients, because nonunion was not recognized and the clinical results over an average 7-year follow-up period were good or satisfactory.