Depuy Products, Inc.

Duane G Synder

Paul Peter Lewis

James G Lancaster

Leanne A Turner

A prosthetic component assembly, such as an acetabular cup, includes a shell and a bearing insert or liner. The shell and bearing insert are configured to provide an increased congruency between the shell and the bearing insert thereby decreasing the amount of motion (i.e. micromotion) between the shell and the bearing insert. In one form, increased congruency is achieved through first and second (inner and outer) tapers that are respectively provided on the shell and the bearing insert. The outer taper has first and second outer taper portions. A relationship between the first outer taper portion and the inner provides an essentially congruent fit, while a relationship between the second taper portion and the inner taper provides an interference fit. The relationships between the inner and outer tapers allow the bearing insert to achieve load sharing at a dome of the outer shell as well as at a rim of the shell. The relationships between the tapers also allow relative motion between the shell and the bearing insert to be controlled. Particularly, the relationships between the tapers allow relative motion, or micro-motion, to be uniformly controlled below previous levels reported in the range of 10 micrometers or less between the bearing insert and the shell.

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Scottsdale, AZ, United States of America

Duane G Synder