Background: Hemiarthroplasty for acute proximal humeral fractures gives disappointing results, often due to rotator cuff insufficiency. Better tuberosity fixation might improve results. Therefore, the aim of this study was to: 1) report the outcome of a stemmed hemiarthroplasty with a common platform system and a modular suture collar; 2) compare the outcome with that of a standard stemmed hemiarthroplasty; 3) report the feasibility of revision arthroplasty with retention of the stem; and 4) to evaluate the association between tuberosity healing and functional outcome. Methods: Forty-four fractures that were deemed not suitable for nonsurgical treatment or open reduction and internal fixation were treated with the Global Unite fracture system between January 2017 and July 2019. The functional and radiographic results at 2 years were compared with the results of 44 Global Fx arthroplasties. The results of patients who had adequate healing of the greater tuberosity were compared with the results of patients who had severe malunion or nonunion (resorption). Results: Mean Oxford Shoulder Score, Constant-Murley Score, and Western Ontario Osteoarthritis of the Shoulder index was 33 (range: 10 to 48), 40 (range: 10 to 98), and 68 (range: 18 to 98) at 2 years. There were no differences in functional outcome scores or in the risk of inadequate healing of the greater tuberosity between the Global Unite and the Global Fx systems. Five (11%) patients underwent revision surgery with retention of the stem. Inadequate tuberosity healing was associated with an inferior Constant-Murley Score (mean difference: 6; 95% confidence interval: 1 to 10, P = .01) and an inferior Oxford Shoulder Score (mean difference: 9; 95% confidence interval: 1 to 16, P = .03). Conclusion: The use of stemmed hemiarthroplasty with a suture collar did not improve the healing of the greater tuberosity or the functional outcome. Five arthroplasties were revised with retention of the stem. This possibility could be arguments for using the Global Unite system when a stemmed hemiarthroplasty is used for acute proximal humeral fractures.