Carpal impaction with the ulnar styloid process (stylocarpal impaction) occurs much less frequently than with the ulnar head (ulnar impaction). The authors report a series of 5 patients with stylocarpal impaction who, after failing non-operative treatment, underwent wrist arthroscopy and open partial resection of the ulnar styloid. At an average follow-up of 37 months, all 5 patients were satisfied with their result and only 1 patient reported residual wrist discomfort.
The authors discuss the physical examination and radiographic findings in stylocarpal impaction. The condition appears to be associated with an excessively long ulnar styloid process; the length of the ulna exceeded 6 mm in all 5 wrists (normal range 3 mm - 6 mm). Although ulnar variance measured negative in each instance, the authors comment that the condition can also develop in ulnar neutral and ulnar positive wrists. They advocate wrist arthroscopy in excluding other causes of ulnar-sided wrist pain at the time of surgery and they caution against resecting too much of the ulnar styloid process which could potentially disrupt the TFCC. If both ulnocarpal impaction and stylocarpal impaction are suspected, an ulnar shortening osteotomy rather than an ulnar styloidectomy is suggested. The conclusions from this study are in agreement with the findings of Topper, Wood and Ruby (JHS 22A: 669-704, 1997).