An intramedullary device assembly is provided for repairing defects of a bone. The intramedullary device assembly includes a device that is configured to be inserted into the medullary canal of the bone. The assembly also includes a guide adapter that attaches to the end of the device and includes a movable and adjustable bone engagement member. Also a compression member may be attached to the guide adapter that pushes the bone engagement member into engagement with the bone. The bone engagement member defines at least two bone engagement points and wherein at least one bone engagement point is movable relative to at least one other bone engagement point in the direction of the bone. The compression member forces the bone engagement member in the direction of the bone along the bone engagement member guide and the at least one bone engagement point is permitted to move relative to the other at least one bone engagement point so that both bone engagement points can engage the end of the bone as compression is applied to the bone. The guide adapter and compression member may then be detached from the intramedullary device. A breakaway stud may also be included to connect the guide adapter to the intramedullary device such that the application of force on the assembly may break the breakaway stud and detach the guide adapter and compression member from the installed intramedullary device.