Dow Corning Wright Corp.

Samuel J Chiarizzio

Kenneth William Russell

Alfred J Fichera

A ball-and-socket joint prosthesis, e.g. a hip joint prosthesis, which comprises an outer shell element, a ball component, and a replaceable bearing insert element positioned between the shell and the ball component. The bearing insert has a generally spherical inside surface which encompasses more than half of the ball component to thereby retain it. The insert has an outside surface shaped to mate with the inside surface of the shell, and the shell element and the insert element have a locking mechanism consisting of a protruding portion which extends a major distance around a side surface of one element which locks into a mating depression in the other element. In a preferred embodiment, the insert is horizontally slotted around a major portion, but less than the entire distance around the insert, above that portion of the locking mechanism present on the insert and is vertically slotted from the bottom of the insert to the horizontal slot thereby forming at least one, but preferably two, movable finger(s). The flexibility of the finger(s) allows the ball component to be inserted into and removed from the insert. Once the insert containing the ball component is locked into the shell, the vertical slot may be at least partially closed by moving the finger(s) to disengage the locking mechanism and allow removal of the insert and the ball component from the shell.

Ball-and-socket joint prosthesis with bearing insert

This invention relates to a femoral trial prosthesis/rasp assembly for use in hip implant surgery. The novel handle assembly grips the combination trial prosthesis/rasp in a secure manner by clamping over and locking onto a post on the trial prosthesis/rasp which later serves as a mounting piece for a femoral prosthesis head used in trial reductions. The handle assembly preferably comprises a straight member which has a recess for reception of one half of the post and a pivotable lever which contains an opposing recess which fits over the remainder of the post when a screw is tightened to bring the two recesses together over the post. The trial prosthesis/rasp is cooperatively engaged by a projection located at the end of the handle assembly to hold the trial prosthesis/rasp in a preselected orientation with respect to the handle assembly during use. The trial prosthesis/rasp is easily released from the handle by turning the screw to permit the lower portion of the straight member and lever to separate.

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Memphis, TN, United States of America

Samuel J Chiarizzio