Bone-implant prosthesis

A prosthesis according to any one of the preceding claims in which the aluminium oxide layer comprises pores having a diameter from 5 to 200 nanometer.

A prosthesis according to any one of the preceding claims in which the bioactive material is of glass or is a hydroxyapatite.

A prosthesis according to any one of the preceding claims in which the aluminium oxide layer comprises 2 to 20% by weight of phosphate.

A prosthesis according to any one of the preceding claims in which the core is made of metal.

A prosthesis according to any one of the preceding claims in which there is no optional intermediate layer of aluminium or an alloy thereof.

A prosthesis according to any one of the preceding claims substantially as described with reference to any one of FIGS. 1 to 8 of the accompanying drawings.

A prosthesis for a ball and socket joint which comprises a cap which co-operates with a cup in which the cap and the cup are of metal, the concave surface of the cap and/or the convex surface of the cup bears an aluminium oxide layer which comprises phosphate and/or pores containing bioactive material, optionally with a layer of aluminium or an alloy thereof between the metal of the cap and/or the cup and its porous aluminium oxide layer.

A process according to any one of claims 19 to 23 in which the size of the pores is increased by etching the surface layer with a material that dissolves aluminium oxide.

A method of repairing a human or animal bone ball-and-socket joint which comprises optionally shaping the ball joint to receive a prosthesis in the form of a cap, attaching the cap to the ball joint and attaching a corresponding cup to the socket joint, optionally after shaping it, such that the concave surface of the cap and/or the convex surface of the cup bears an aluminium oxide layer which comprises phosphate and/or pores containing bioactive material.