 This multicentre prospective randomized trial will involve the Canadian Orthopaedic Trauma Society COTS, an association of trauma surgeons involved in collaborative outcomes research with a proven track record of research and publication. Patients with a humeral diaphyseal fracture who meet all eligibility criteria and provide consent to participate will be randomly assigned to the operative or splintbrace treatment group. Patients will start physiotherapy at 2 weeks post-randomization splintbrace groupor 2 weeks post-surgery for gentle ROM exercises. The operative group will progress to strengthening and proprioception at 4-6 weeks. The splintbrace group will only progress at the 6-8 weeks mark once union has occurred. Evaluation at 2 and 6 weeks, 4, 6, and 12 months will include functional, clinical and radiological parameters. Functional evaluation will include the DASH, SMFA questionnaires and the Constant Shoulder Score. Clinical outcome will evaluate range and motion including the shoulder and elbow of both the affected arm and contralateral shoulder and elbow. Standard radiographic parameters will be measured. The primary outcome measure will be functional outcome as measured with the DASH. Appropriate statistical analyses will be performed on the data. Sample size calculation reveals the need for 90 patients per treatment arm. A census of the centers committed to the study predicts a 1-24 month recruitment period. Patient follow-up will end at the 12 month visit. 