Coated femoral stem prosthesis

DETAILED DESCRIPTION We claim: 1.
A femoral hip joint prosthesis having reduced adhesion to bone cement comprising: a proximal stem portion; and a distal stem portion for contact exclusively with bone cement lining a bone cavity, said distal stem being formed from metal having a polished surface finish coated with a discrete layer of diamond-like carbon to reduce adhesion to bone cement, said layer of diamond-like carbon being from about 1 to 30 microns thick with an outer surface maintaining said polished surface finish.
2.
The femoral hip joint prosthesis of claim 1 wherein said layer of material is greater than 1 micron thick.
3.
The femoral hip joint prosthesis of claim 2 wherein said layer of material is from about 1 to 3 microns thick.
4.
A femoral hip prosthesis having reduced adhesion to bone cement comprising: a head and neck proximal portion; and an elongated stem portion for contact exclusively with bone cement lining a bone cavity extending from said proximal portion to a distal end, said stem having a medial, lateral, anterior and posterior surfaces, said surfaces tapering downwardly from said proximal portion to said distal end, said stem being formed from metal having a polished surface finish coated with a discrete layer of diamond-like carbon to reduce adhesion to bone cement, said layer of material is from about 1 to 3 microns thick with an outer surface maintaining said polished surface finish.
5.
The femoral hip joint prosthesis of claim 4 wherein the polished surface has a roughness of less than about 4 microinches.
6.
The femoral hip joint prosthesis of claim 5 wherein said layer of material is greater than 100.
ANG.
thick.
7.
The femoral hip joint prosthesis of claim 6 wherein said layer of material is from about 1 to 3 microns thick with an outer surface maintaining said polished surface roughness.




Description:
BACKGROUND OF THE INVENTION 1.
Field of the Invention The present invention relates to a hip joint prosthesis and more particularly to a femoral component of such a prothesis which is coated with a material which reduces the bonding of the prosthesis to bone cement