Centering osteotomy for treatment of posterior shoulder dislocation in obstetrical palsy.

BACKGROUND The main objective of this study is to describe a new surgical technique that, through a gleno-humeral approach, reduces the incongruent joint while a humeral head centering osteotomy achieves shoulder stabilization. A humeral medial derotational osteotomy is performed associated with the articular reduction. PATIENTS AND METHODS Fourteen patients with obstetrical palsy presenting a posterior humeral head dislocation were submitted to a centering osteotomy procedure. Our study included patients with: (1) more than 1.5 years postoperative follow-up, (2) presence of humeral head posterior dislocation. The exclusion criteria were the following: (1) patients with total flaccid paralysis, (2) low paralysis and (3) any kind of active infection at the time of the procedure. RESULTS Before treatment, in all patients, the shoulder joint was posteriorly dislocated and in internal rotation. All patients went on to have successful healing at the osteotomy site. In all cases, an improvement in the functional Mallet scale was observed. In all patients, except one, the posterior dislocation was corrected. In two cases, a second surgery (external derotation osteotomy) was performed to improve the upper extremity's position. CONCLUSIONS Articular congruency, after posterior dislocations of the humeral head, is achieved by humeral head centering osteotomy in patients with obstetrical palsy late deformities and also improves function. LEVEL OF EVIDENCE Level IV; case series.