Treatment of complex proximal humeral fractures remains controversial. In situations where accurate fracture reduction and fixation cannot be obtained, arthroplasty may be the preferred surgical option. The traditional operation of hemiarthroplasty in these situations is technically challenging, and a good functional outcome is dependent on reduction and healing of the tuberosities. Reverse Shoulder Arthroplasty (RSA) has been suggested as an alternative, and we sought to analyse and compare functional outcomes following the two procedures. Ten patients who underwent hemiarthroplasty for acute fracture of the proximal humerus between 1999 and 2003 were reviewed. All fractures were assessed intraoperatively for open reduction and internal fixation of the fracture, but deemed to be unsuitable for fixation. From 2003 our management in this clinical situation changed, and ten subsequent patients underwent reverse shoulder arthroplasty using the S.M.R. reverse shoulder prosthesis (Systema Multiplana Randell, Lima, Italy). Clinical and radiological follow up was carried out at a mean of 31 months (hemiarthroplasty patients) and 15 months (RSA patients) post operatively. Subjectively seven of 10 patients in the reverse group and seven of 10 patients in the hemiarthroplasty group rated their outcome as ‘very good’ or ‘excellent’. The mean ASES scores were 65 (range 40–88) in the reverse group and 67 (26–100) in the hemiarthroplasty group. The mean Oxford shoulder score was 29 (15–56) in the reverse group and 22 (12–34) in the hemiarthroplasty group. The mean active forward elevation in the hemiarthroplasty group was 108° (range 50–180) and in the reverse group 115° (45–40), and active external rotation 49° (5–105) and 48° (10–90) respectively. Differences in outcome scores between the two groups were not statistic ally significant (p value>
0.05). This study provides the first direct comparison between RSA and hemiarthroplasty for complex proximal humeral fractures. The expected functional gains with Reverse shoulder arthroplasty were not seen, suggesting its use as the primary treatment for acute fracture should remain guarded.