Background To investigate the functional outcomes of reverse shoulder arthroplasty (RSA) in acute complex proximal humerus fractures (PHF) in patients with an anatomic greater tuberosity union in comparison to patients with a displaced or resorbed tuberosity. Method: It is a retrospective study with prospective data collection including 32 consecutive PHF with a minimum two-year follow-up treated with RSA. A radiological study and a CT scan were performed specifically for the study. Two shoulder surgeons and a musculoskeletal radiologist assessed the position and union of the greater tuberosity. The functional outcomes were assessed with the Constant-Murley, DASH, ASES and ADLER scores. Results: The mean overall CS was 59.55. In 17 cases, the greater tuberosity healed in an anatomical position. In 15 cases, it was non-anatomical. In 53% of patients, greater tuberosity union was obtained. The CS was 62.76 in the anatomic union group and 55.9 in the non-anatomic union group. No significant differences were observed. No differences were observed in the ASES, DASH and ADLER scores. Conclusion: After RSA for PHF, anatomic greater tuberosity healing was obtained in 53% of patients. The influence of the position and union of the greater tuberosity on the functional results could not be evidenced.

Background The assessment of tuberosity position and union in reverse shoulder arthroplasty (RSA) for complex proximal humerus fractures (PHF) has been carried out by means of routine simple radiographs. To evaluate the interobserver agreement and intraobserver reproducibility of the simple radiograph in comparison to the CT scan. Methods The position and consolidation of the tuberosities in 2 radiographic projections and in a CT scan of 32 consecutive patients operated on a RSA for PHF was assessed by 5 observers. Interobserver agreement and intraobserver reproducibility in both imaging tests were also assessed. Results The interobserver agreement for the greater tuberosity position was 0.52 in the simple radiograph and 0.45 in the CT scan. For the greater tuberosity union, agreement was moderate in the simple radiograph (0.52), but fair in the CT scan (0.35). For the lesser tuberosity position and union, the agreement was fair in the radiograph and poor in the CT scan. Conclusion Only moderate agreement was observed in the assessment of the position and union of the tuberosities in the RSA for PHF in the simple radiograph and no improvement in it was seen for the 2D CT scan.