Stability in relation to humeral head retroversion after surgical treatment of recurrent anterior shoulder dislocations.

Abstract

This study reports the influence of the retroversion angle on the postoperative stability in 50 patients operated on for recurrent shoulder dislocations. Fifty-two shoulders were reviewed by radiographic and clinical examinations. Particular attention was focused on humeral head retroversion, shoulder stability, and range of motion in relation to surgical technique. The retroversion angle was significantly reduced in 30 of 47 shoulders, for which satisfactory radiographs could be achieved. Mean humeral head retroversion was 24 degrees for both dominant and nondominant shoulders. Forty-eight of 52 reexamined shoulders became stable. Four had remaining instability following a Putti-Platt procedure, with a mean retroversion angle of 18 degrees. A reduced humeral head retroversion is therefore proposed as an important factor in creating instability, and may be one explanation for failed stability after soft tissue repair. Irrespective of the type of surgical procedure (Bristow or Putti-Platt), there was a significant decrease in range of shoulder rotation in the operated shoulder compared to the contralateral stable shoulder and to reference values for normal controls. However, decreased rotation was not found to impair shoulder function, and 48 of the 50 reexamined patients generally improved after surgery.