Background: Ulnar shortening osteotomy (USO) is an effective treatment for ulnar impaction syndrome. However, there has been a concern of osteoarthritis (OA) developing at the distal radioulnar joint (DRUJ) if USO is performed on patients with a reverse oblique sigmoid notch. This study aimed to evaluate the radiographic and functional outcomes following USO in patients with a reverse oblique sigmoid notch.
Methods: We retrospectively reviewed our patients with a reverse oblique sigmoid notch who underwent USO to treat ulnar impaction syndrome between 2002 and 2013. We evaluated the radiographic changes of the DRUJ and the patients’ functional outcomes.
Results: We enrolled 22 patients (22 wrists) with an average age at operation of 49.6 years and mean follow-up of 93.2 (range, 36 - 179; SD 38.2) months. We found that there were changes in the inclination angle of the sigmoid notch, from an average of reverse oblique 14.9o (range, 11o - 23o; SD 3.4o) preoperatively to a more parallel 5.1o (range, 0o - 11o; SD 3.2o) at the final follow-ups. The functional results at the final follow-ups were good with a mean VAS for pain of 0.2 (range, 0 - 1; SD 0.4) at rest and 1.3 (range, 0 - 3; SD 0.9) during activity, QuickDASH of 15.1 (range, 2.3 - 34.1; SD 8.8), and modified Mayo Wrist Score of 91.6 (range, 70-100; SD 6.4). Seven wrists (31.8%) were noted to have OA changes, but the wrists did not exhibit a significantly worse function when compared to wrists without OA changes, except for supination motion and grip strength.
Conclusions: For those patients with a reverse oblique sigmoid inclination following USO, the inclination angle would have a tendency to become more parallel and some patients would develop OA changes at the DRUJ, but the functional outcomes could still be good in the long term. The reverse oblique sigmoid inclination seems not to be an absolute contraindication for USO.