The present application relates to a cross pin fixator device comprising a plate member with spherical cavities that are open to the front and to the back of the plate, collapsible pin holder members having a central channel for insertion of a bone pin, the collapsible pin holder member being press-fit into the spherical cavities, and bone pins individually inserted into the central channel of a pin holder. The application also relates to a method for treating a fracture of the proximal humerus using the proximal humerus cross pin fixator and to a kit for treating a fracture of a bone.