An orthopedic bone fixation device including an anchor member having a cavity and an insert member. The SCU uses a power sourcestorage device, such as a rechargeable battery. A slave spring is arranged in coaxial relationship to the load-carrying spring and has one end received in the receptacle and another end intended for engagement with the stop surface of the abutment. Mounting portions are provided on the bottom surface side of the ink tank. The system may have a controller in communication with the optical sensing device and at least one of the first and second signal devices. The diaphragm is disposed between the sleeve and the housing to form an annular chamber.