Carpal tunnel syndrome caused by volar dislocation of the lunate in a patient with rheumatoid arthritis

We report a case of carpal tunnel syndrome caused by volar dislocation of the lunate in a patient with rheumatoid arthritis. A 74-year-old woman complained of numbness in her fingers. Carpal tunnel syndrome was diagnosed, and carpal tunnel release was performed. However, the symptoms recurred. Three-dimensional computed tomography and magnetic resonance imaging revealed volar dislocation of the lunate and synovitis around the distal radioulnar joint, respectively. Resection of the lunate and the Sauvé-Kapandji procedure were effective.