Inventors:
Jennifer K. Bow - Philadelphia PA, US
Joshua M. Pearce - Philadelphia PA, US
International Classification:
A61N 1/00
Abstract:
In this invention, stress shielding effects seen in total joint arthroplasty patients and trauma patients is prevented by causing the bone above the press fit of the implant to continue to act as if it were under stress by inducing an electric field in the surrounding bone that simulates the electric field generated when bone is under mechanical stress. This same effect is used to stimulate bone union in fractures and surgical arthrodesis, as well as to encourage increased bone mass and consolidation of bone during limb lengthening procedures. The electric field can be generated by a number of methods utilizing scavenged energy, with the preferred embodiment being the generation of electricity using arrays of thousands of thermoelectric generators built into an implantable chip. These generators exploit the well-known thermocouple effect, in which a small voltage is generated when two of the junctions between two dissimilar materials are kept at different temperatures. The temperature gradient is produced between the underside of the skin and the interior of the body.