The aim of this study was to report the outcome of radial head replacement for complex fractures of the radial head, and determine any risk factors for prosthesis removal or revision. We identified 119 patients who were managed acutely using primary radial head replacement for an unstable fracture of the radial head over a 15-year period. Demographic data, fracture classification, management, complications and subsequent surgeries were recorded following retrospective clinical record review. There were 105 (88%) patients with a mean age of 50 yrs (16–93) and 54% (n=57) were female. There were 95 (91%) radial head fractures and 96% were a Mason type 3 or 4 injury. There were 98 associated injuries in 70 patients (67%), with an associated coronoid fracture (n=29, 28%) most frequent. All implants were uncemented monopolar prostheses, with 86% metallic and 14% silastic. At a mean short-term follow-up of 1 year (range, 0.1–5.5; n=87) the mean Broberg and Morrey score was 80 (range, 40–99), with 49.5% achieving an excellent or good outcome. At a final mean review of 6.7 yrs (1.8–17.8), 29 (27%) patients had undergone revision (n=3) or removal (n=26) of the prosthesis. Independent risk factors of prosthesis removal or revision were silastic implant type (p=0.010) and younger age (p=0.015). This is the largest series in the literature documenting the outcome following radial head replacement for complex fractures of the radial head. We have demonstrated a high rate of removal or revision for all implants, with younger patients and silastic implants independent risk factors.