Metatarso-phalangeal joint prosthesis for use with foot

摘要

The prosthesis consists of a metatarsal implant (1) with a thrust shield, and a phalangeal implant (2) with a concave face (4) designed to interact with the thrust shield. Each of the implants has a truncated conical shank (5,6) for insertion and fixing in the spongy tissue of the bones. Each of the two implants is made in one piece with a coating of a ceramic material on their interacting surfaces. In addition, the metatarsal implant has two diametrically opposite flats (7) on the edges of its shield, and the phalangeal implant has a number, preferably three, of equally-spaced notches (8) for manoeuvring it. The two implants are preferably made from titanium of type TA6VA, and their ceramic coatings are applied by the Hexaplasma (RTM) procedure, using a compound based on chrome oxide, doping agents, oxides, carbides and hexagonal crystals of the thrust shield, and another compound based on chrome oxide and tungsten carbide coated with cobalt, with doping agents to improve its mechanical properties, for the concave face.