54 patients with displaced Neer 2- or 3-part proximal humerus fractures were randomized to undergo proximal humerus nailing using either MultiLoc proximal humeral nails (MPHN) (straight intramedullary nail) or Polarus intramedullary nails (curvilinear nail), with the purpose of comparing clinical outcomes, radiographic results, and complications between treatment groups. While constant shoulder scores and mean neck-shaft angles did not significantly differ between groups, the MPHN group had significantly lower screw loosening and rotator cuff dysfunction compared to the polarus group.