Patent ID: 8491583

Claim:
An intramedullary medical device adapted to provide contracting forces between a patient's bones, the intramedullary medical device comprising: (a) an encasement adapted to connect under compression separate bones of an ankle joint including a tibia, a talus, and a calcaneus; (i) wherein a proximal end of the encasement is adapted to be fixed within a medullary canal of the tibia; (ii) wherein a distal end of the encasement is adapted to be fixed within the calcaneus; (iii) wherein an intermediate portion of the encasement between the proximal the distal end is adapted to be installed within the talus; (b) a distal anchor element contained within the distal end of the encasement; (i) wherein the distal anchor element is adapted to be fixed to the calcaneus; and (c) a non-linear contracting element contained within the encasement; (i) wherein the non-linear contracting element is connected between an internal surface of the encasement and an internal surface of the distal anchor element; (ii) wherein the non-linear contracting element is adapted to provide compression between the separate bones of the ankle joint through moving the distal anchor element within the encasement toward the proximal end of the encasement; (iii) wherein the non-linear contracting element comprises a shape memory alloy adapted to exhibit a pseudo-elastic stress-strain response over a pseudo-elastic range of expansive strain imparted to the non-linear contracting element based on the distal anchor element being moved distally with respect to the proximal anchor element; (iv) wherein the non-linear contracting element is further adapted to hold the separate bones of the ankle joint in direct contact and under compression through the encasement, the distal anchor element, and the proximal anchor element, while the non-linear contracting element provides compressive forces via the pseudo-elastic stress-strain response of the shape memory alloy as a result of the expansive strain imparted on the shape memory alloy.