Proximal humeral fractures remain a surgical challenge, and scientific discussions are commonly focused on their ideal treatment. One possible treatment involves the use of an angle stable plate osteosynthesis. However, which material can most feasibly be used to attach the greater tuberosity to the implant remains unknown. In two prospective, non-randomized trials, we compared the results of a FiberWire® and a wire cerclage. A total of 104 patients with 3- and 4-part fractures were included in this examination. In 25 cases, the greater tuberosity was fixated with a FiberWire®, size 2, while 79 cases received a wire cerclage. Plate osteosynthesis was constantly performed via the anterolateral delta-split approach using the NCB®-PH-plate by Zimmer®. The patients were followed clinically at discharge, 6 weeks and 6 months postoperatively and were examined for relevant complications. Age and gender were equally distributed in both groups. Concerning the follow-up after 6 weeks, a significant benefit concerning shoulder function was observed in the FiberWire®-group (wire cerclage: 39.20±11.85, 95% CI 32.37-44.56, FiberWire®: 45.84±16.80, 95% CI 28.34-61.56: p=0.049). After 6 months, the difference between the groups was not significant (wire cerclage: 58.13±18.73, 95% CI 50.25-72.40, FiberWire®: 68.85±23.10, 95% CI 46.83-99.53: p=0.06).