Radiocarpal fusion.

Limited wrist fusion is a common and often effective method of treatment for many painful wrist conditions. When post-traumatic, inflammatory and noninflammatory arthritis affects only the articular surfaces of the proximal carpal joint, a limited radiocarpal fusion can be considered. Specific indications are painful arthritis following distal radial fractures, rheumatoid arthritis with ulnar shift of the carpus, scapholunate instability with radioscaphoid arthritis, and stage IV Kienbock's disease. It is necessary for the midcarpal joint surfaces to be essentially normal. Either a radioscapholunate or radiolunate fusion can be performed, depending on the underlying condition. Up to 70 degrees of wrist flexion-extension can be obtained after a radioscapholunate fusion. Keys to a successful postoperative result are proper alignment of the scaphoid and lunate, use of bone graft or bone graft substitute and careful positioning of internal fixation devices. Evidence of radiographic union is usually seen by eight weeks. Nonunion rates are quoted to be from 10 to 20%.