A proximal humeral plate assembly can include a first plate, a coupler, a second plate, and a guide. The first plate can define a window and can have a first major surface adapted to conform to a native bone structure. The coupler can be formed on a second major surface of the first plate opposite the first major surface. The second plate can be adapted to engage the coupler, to cover the window, and to conform to the native bone structure. The second plate can include through holes adapted to receive bone screws. The guide can be adapted to engage the coupler and to guide at least one of a cutting tool and a dilation tool.