Ulnar styloid impaction syndrome.

A series of 8 patients each with an excessively long ulnar styloid that was impacting the triquetrum, causing chondromalacia, synovitis, and pain, is presented. Four patients developed symptoms as a result of an injury and 4 had no definable acute precipitating injury. The average age at the time of surgery was 34 years. There were 3 male and 5 female patients. The average follow-up period was 34 months. All patients were treated by open partial ulnar styloidectomy. Outcome was evaluated clinically and by means of patient questionnaire and radiographs. Pain decreased from a preoperative average score of 3.5 to a postoperative average score of 1.3, which equates to mild pain requiring no medication. All but 1 patient returned to their previous employment unrestricted. The average preoperative ulnar styloid length was 7.4 mm and the average ulnar styloid process index was 0.41, which is almost twice normal. There were no complications. It is likely that an excessively long ulnar styloid has important implications for the kinematics of the lunatotriquetral interval. Details of the diagnosis of this condition, including a new provocative test, and operative management are discussed.