68 patients with simple-type humeral shaft fractures underwent minimally invasive plate osteosynthesis (MIPO) or conventional open plating to compare clinical, functional, and radiological outcomes. Patients in both treatment arms experienced excellent elbow and shoulder function one year postoperatively and similar rates of complication. Both groups reported a high rate of healed fractures between 15-16 weeks, 97% of fractures being healed at this time in the open plating group and 100% in the MIPO group. The only differences observed between treatments were less blood loss and a greater time of radiation exposure in the MIPO patients.