Postoperative Radiographic Outcomes Following Abduction-Extension Metacarpal Osteotomy: A Comparison between Early and Advanced Carpometacarpal Arthritis.

This study aimed to investigate the effect of thumb metacarpal osteotomy on dorsal subluxation of the carpometacarpal (CMC) joint and compare the effects of early and advanced osteoarthritis (OA). We retrospectively reviewed 42 thumbs of 37 patients who underwent metacarpal osteotomy with a postoperative extension angle of 90° or more between January 2018 and October 2021 and were followed up for more than 2 years. The thumbs were classified into two groups: early OA (Eaton stage I or II) and advanced OA (Eaton stage III). We measured the reduction ratio, which was defined as the ratio of improvement in dorsal subluxation, at 3 months and 1 year postoperatively, and at the latest follow-up. We statistically compared the reduction ratio between the two groups and investigated the factors affecting the reduction ratio using correlation analysis. The reduction ratio was significantly higher in the early OA group than in the advanced OA group at 3 months after surgery, whereas no significant difference was found between the two groups at 1 year after surgery and at the latest follow-up. A significant positive correlation was detected between the reduction ratio and the postoperative extension angle. First metacarpal osteotomy reduces dorsal subluxation in both early- and advanced-stage CMC OA. This procedure yields immediate marked reduction in early-stage OA, while improvement of the subluxation progressed gradually in advanced-stage OA. Level IV (Therapeutic).