An implantable orthopaedic knee prosthesis assembly includes a femoral component, a stem component, a fastener, and a retention device. The femoral component is configured to be implanted into a distal end of a femur of a patient and includes a stem post having a proximal tapered bore, a distal passageway, and a threaded passageway connecting the proximal tapered bore and the distal passageway. The stem component is configured to taper fit to the femoral component and includes a bore formed therein extending proximally and a threaded aperture defined at a proximal end of the bore. The head of the fastener is configured to be received in the distal passageway, whereas the proximal end of the shaft of the fastener is configured to be positioned in the threaded aperture. The retention device is received in the threaded passageway and prevents the proximal end of the fastener from entering the threaded passageway.
