The metaphyseal bone defect predicts outcome in reverse shoulder arthroplasty for proximal humerus fracture sequelae

Reverse shoulder arthroplasty (RSA) represents an established procedure for treatment of fracture sequelae (FS) after proximal humerus fractures. The present work evaluates which factors are of influence for the clinical outcome. Fifty cases (mean age 69, range 44-89) have been evaluated postoperatively clinically [Constant Score (CS)] and radiographically (mean FU 34; range 24-93 months). The type of primary treatment, the amount of a metaphyseal bone defect, the preoperative status of the rotator cuff, the number of previous operative interventions and the type of FS according to Boileau were analysed whether they are of influence for clinical outcome. The mean CS increased significantly from 16.9 ± 6.7 preoperatively to 54.1 ± 15.7 points postoperatively. The CS of primary conservative treatment was significantly higher in comparison to primary operative treatment. Patients with a metaphyseal bone defect of more than 3 cm had significantly lower CS results. Degenerative changes of the teres minor muscle also had a significant negative influence on clinical results. Score results decreased with increasing number of previous operations. There were no significant difference in between patients classified as Boileau type I and II (category 1) compared to types III and IV (category 2). RSA significantly improved the clinical result. A metaphyseal bone defect and preoperative degeneration of the teres minor showed to be negative prognostic factors. Primary operative treatment and the number of previous operations also negatively influenced the clinical result.