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US 5,123,924 AGranted
Surgical implants and method
AssigneeSpire Corporation
InventorsPiran Sioshansi, Eric J. Tobin
Life of this patent
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Abstract
An improved surgical implant, formed of cobalt-chromium and its alloys in contact with a bearing surface formed by UHMWPE, and a process of its manufacture are disclosed. The improved surgical implant is designed to reduce the wear of the UHMPE component of the surgical implant, enhancing its useful life. The process essentially includes the ion implantation of the cobalt-chromium component, with a resultant increase in its microhardness and a decrease in its coefficient of friction, particularly when articulating against the UHMWPE component.
Claims5
A surgical implant comprising:
- (a) an implant formed of two parts:
- a first part formed of metal and, a second complementary part formed of plastic;
- (b) said first metal part is formed of a cobalt-chromium alloy and said second plastic part formed of UHMWPE;
- (c) said first metal part being ion implanted with one of a group consisting of N.sup.+, N.sub.2.sup.+, C.sup.+, Ti.sup.+, O.sup.+, P.sup.+, Ne.sup.+, He.sup.+, Kr.sup.+, Ar.sup.+ and B.sup.+ so as to create a surface region therein characterized by an increase in its microhardness and a decrease in its coefficient of friction when rubbing against said second plastic part;
- (d) said ion implantation being effected with an ion beam power density acting on said surface region being between about 1.00 watt/cm.sup.2 to about 6.0 watt/cm.sup.2 ;
- (e) said second complementary plastic part being used as a load bearing surface supporting said surface region of said first ion implanted metallic part constantly articulating against it such that said constant articulating does not adversely affect said load bearing surface;
- (f) said ion implanted first metal part is characterized by improved surface homogeneity and resistance to chemical attack and wherein said microhardness of said metal part is at least about 1300 Knoop for a 10 gram load.
4 more elements
Dependencies are inferred from the claim text.