The ulnar impaction syndrome.

The ulnar impaction syndrome can be defined as the impaction of the ulnar head against the triangular fibrocartilage complex and ulnar carpus resulting in progressive degeneration of those structures. The differential diagnosis in patients who present with ulnar wrist pain and limitation of motion can also include ulnar impingement syndrome and arthrosis or incongruity of the distal radioulnar joint. Structural abnormalities involving the distal radioulnar joint, distal radius, and ulnar carpus must be carefully elucidated prior to developing a treatment plan. When such abnormalities are identified and appropriately addressed, surgical treatment can be expected to be effective in the majority of cases. It is important to remember that in the absence of obvious structural abnormalities, the ulnar impaction syndrome may result from daily activities that result in excessive intermittent loading of the ulnar carpus. In this group of patients, treatment is directed at decreasing ulnar load by shortening the distal ulna in any of several ways. If relative instability of the ulnar ligamentous complex is a factor, then ulnar shortening by recession is the treatment of choice. Malunion of the distal radius resulting in ulnar impaction syndrome is best treated by addressing the deformity; that is, corrective radial osteotomy. Patients who present with a combination of ulnar impaction syndrome along with distal radioulnar joint, abnormalities must have both of these abnormalities addressed at the time of surgery. The matched ulnar resection and the hemiresection interposition arthroplasty are both effective procedures; however, the Suave-Kapandji procedure also can be used to address relative ligamentous laxity at the ulnar aspect of the wrist. The Darrach procedure is presently not recommended as a first-line treatment in these cases; however, when used as a salvage procedure, satisfactory results can be obtained in properly selected patients. Careful preoperative evaluation and planning are therefore the key to successful treatment of the ulnar impaction syndrome.