Background: Comminuted radial head fractures are challenging to treat with open reduction and internal fixation. Radial head arthroplasty is a favourable technique for the treatment of complex radial head fractures. The purpose of this study was to evaluate the functional and radiological outcomes of radial head arthroplasty using modular pyrocarbon radial head prosthesis. Methods: We retrospectively reviewed 21 consecutive patients requiring radial head arthroplasty for unreconstructible radial head fractures between July 2003 and July 2009. Patients completed a Short Form-36 (SF-36), the Disabilities of the Arm, Shoulder and Hand questionnaire, and the Mayo Elbow Performance Index. Patients were independently physically examined and their post-operative radiographs were reviewed. Results: Twenty-one patients (nine males and 12 females) were reviewed at a minimum of 12 months follow-up. The mean Disabilities of the Arm, Shoulder and Hand score was 10.8 (0-34.1), mean SF-36 physical score was 76.9 (35-96), mean SF-36 mental score was 83.8 (60-94), and their Mayo Elbow Performance Index score was 86.4 (70-100). Patients maintained 90% of their grip strength when compared with their uninjured arm and had 17.5°of fixed flexion in the affected arm. Radiologically, 14 cases had some degree of post-traumatic osteoarthritis, 12 cases had evidence of heterotrophic ossification, five had some evidence of periprosthetic lucency and three patients were radiologically, but not functionally 'overstuffed'. Conclusion: Radial head arthroplasty with pyrocarbon radial head prosthesis is an acceptable option when treating unreconstructable radial head fractures yielding good functional and radiological outcomes.