Ulnar shortening osteotomy for treatment of ulnar impaction syndrome: pre-and post-operative radiographic changes and their clinical significance

Abstract

Objective To investigate the pre-and post-operative radiographic changes and clinical significance of ulnar shortening in the treatment of ulnar impaction syndrome.Methods Between August 2008 and November 2011,16 wrists of 14 patients were diagnosed with ulnar impaction syndrome were treated with ulnar shortening osteotomy.Postoperatively the patients were follow-up for a mean of 24.2 months.The pre-and postoperative X-rays and MRI images were compared to analyze the clinical significance of these changes.Results Bone union was achieved at the osteotomy site in all 16 cases.The degree of ulnar variance changed from (4.20 ± 1.70) mm preoperatively to (0.05 ± 1.10) mm postoperatively.Of the 7 wrists that had preoperative bone density changes,5 had near normal density of the carpal bones postoperatively.Subluxation of the distal radioulnar joint in 6 wrists was greatly improved after the operation.Two wrists developed arthritis of the distal radioulnar joint,while 1 wrist had wrist instability and lunate necrosis.MRI signal changes in the carpal bones were noted in 8 wrists.These were manifested as preoperative long T1 and long T2 signals.Postoperatively MRI signals returned to normal in 5 wrists,while myeloid high-intensity zone was present in low-intensity lesions on T1 in 3 wrists.Conclusion Most ulnar impaction syndrome cases have X-ray changes or MRI signal abnormalities in lunate,triangular bone or capitulum ulnae.These changes will return to normal after ulnar shortening osteotomy.However the occurrence of distal radioulnar joint arthritis and lunate necrosis should not be overlooked. Key words: Ulna; X-ray,diagnosis; MRI; Ulnar impaction syndrome