© 2018 Turkish Association of Trauma and Emergency Surgery.BACKGROUND: The radial head is essential for the rotational stability of the forearm and resistance to valgus stress. Radial head fractures are the most common elbow fracture in adults. Various treatment options are available, depending on the fracture severity. However, the treatment of Type-III fractures is controversial. The aim of this study was to evaluate functional results in patients with irreparable Mason Type-III radial head fractures treated with radial head resection or prosthesis. METHODS: Fourteen irreparable Mason Type-III radial head fracture patients treated with radial head resection (n=7) or radial head prosthesis (n=7) were evaluated in this multicenter, retrospective study. Disabilities of the Arm, Shoulder and Hand (DASH) and Mayo Elbow and Wrist scores were used to determine clinical outcomes. A hydraulic hand dynamometer was used to measure grip strength on the operated and unoperated sides to avoid potential bias. Measurements were made three times for each extremity, and the mean value was recorded. Grip strength was calculated as a percentage of the strength of the unoperated side. RESULTS: Functional outcomes for resection and prosthesis patients were the following: mean DASH scores, 25.8 and 17.2; mean Mayo Elbow scores, 74 and 84.1; mean Mayo Wrist scores, 84 and 92.5; and maximum grip strengths, 48.8% and 77.8%, respectively. The range of motion of the respective resection and prosthesis groups were as follows: flexion, 112.14° and 104.29°; extension, −10.00° and −25.00°; pronation, 70.00° and 47.86°; and supination, 70.00° and 52.14°. CONCLUSION: Although range of motion was restricted in the radial head resection group, functional results and grip strength were superior in patients treated with a radial head prosthesis. These results support the radial head prosthesis as a superior treatment modality for patients with irreparable Mason Type-III radial head fractures with respect to patient satisfaction and functional outcomes.