[Reverse shoulder arthroplasty for primary fracture treatment. Displaced three and four part fractures of the proximal humerus in the elderly patient].

The treatment of comminuted three and four part fractures of the proximal humerus in elderly patients with degenerative rotator cuff tears is challenging. Primary reverse total shoulder arthroplasty (RSA) is an alternative; however, functional outcome is still unclear due to a lack of study results. The aim of this study was to examine the functional results of RSA and to compare them with the results after reconstruction and locking plate osteosynthesis 1 year after surgery.In this study 24 patients (mean age: 77.9±9.1 years) underwent RSA as primary treatment for three and four part fractures of the proximal humerus with either head split or rotator cuff tears >Bateman type II. The results obtained at 3, 6 and 12 months follow-up included shoulder range of motion (ROM), Constant score, age-adjusted and gender-adjusted Constant score and as a percentage when compared to the uninjured side. Data were compared to patients of matching age, gender and fracture pattern from a prospectively collected database of 526 patients treated by locking plate osteosynthesis.The mean shoulder ROM 1 year after surgery was 105±29° flexion, 99±31° abduction, 22±23° external rotation and 65±26° internal rotation. In 6 patients flexion-abduction was >130°. The mean Constant score (CS) 1 year postoperatively was 62.4±14, age and gender normalized CS was 79.2±20.5, CS compared to the uninjured side was 76.1% and there were no significant differences to matched individuals treated by open reduction and internal fixation using locking plates (p=0.360). There were no infections, dislocations, vascular or neural disorders and surgical revision was not necessary in any patient. RSA should be considered as an appropriate alternative for the primary treatment of comminuted three and four part fractures of the proximal humerus with head split or large rotator cuff tears in elderly patients. Although RSA can provide immediate shoulder stability for elderly patients with severe shoulder injuries, primary RSA needs investigation with regards to long-term outcome.