Fourteen patients with pain and limited forearm rotation were treated with a modified Darrach procedure involving a distally based slip of the extensor carpi ulnaris tendon. Seven patients had Colles' fractures, four had rheumatoid arthritis, and three had primary osteoarthritis of the distal radioulnar joint. Patients were assigned to one of two groups: rheumatoid arthritis or Colles' fracture/osteoarthritis. The average age was 50 years. Follow-up averaged 54 months (range, 12 to 96 months). The average amount of ulnar resection was 10 mm (range, 6 to 20 mm). In the Colles' fracture/osteoarthritic group, average grip strength (a percentage of the uninvolved hand) improved from 26% preoperatively to 74% postoperatively, and in the rheumatoid arthritis group it improved from 67% to 144%. Distal ulnar instability of the dorsal side was not observed on x-ray examination. Patients were satisfied with pain relief, and all returned to their original work.