Reversed shoulder arthroplasty with inversed bearing materials: 2-year clinical and radiographic results in 101 patients

INTRODUCTION: This study documents 2-year clinical and radiographic results following reversed total shoulder arthroplasty using a novel prosthesis with inverted bearing materials (polyethylene glenoid; metal humeral component). This design was intended to avoid massive PE abrasion on the humeral side. Therefore, we predicted a lack of subsequent osteolysis-induced exacerbation of scapular notching, and because of other design features and modified operating technique a reduced notching rate. MATERIALS AND METHODS: An ongoing, prospective, international, multicenter study of patients implanted with a novel prosthesis at six European centers. The current analysis presents 2-year follow-up data (patients operated between December 2007 and July 2009). Clinical evaluation tools comprised the Constant–Murley score (CS), the American Shoulder and Elbow Surgeon score, range of motion, and a visual analog scale to assess pain and satisfaction. Radiographs were evaluated for notching and radiolucent lines. Any complications were recorded. RESULTS: In total, 113 prostheses (113 patients) with a mean follow-up of 27.6 (±3.6) months were analyzed. CS increased from 22.5 (±13.7) to 65.3 (±14.9) points (p = 0.06). Inferior scapular notching (only grade 1 and 2) was identified in 20.5 % of patients, with no signs of PE-induced osteolysis. 4.4 % of patients experienced an implant-related complication. CONCLUSIONS: Inversion of the materials led to another type of notching with no signs of PE-induced osteolysis and no increase in the risk of short-term complications. Clinical results were comparable with other prostheses. Mid- to long-term results are required before any firm conclusions on clinical outcome and survival can be drawn.