Modular joint prosthesis assembly and method of removing

Claim 2

In a modular prosthetic joint of the type wherein a bearing head has a bore therein which frictionally mates with a tapered shaft of a stem portion of the joint, the improvement which comprises: the bearing head having a generally thin wall defining its continuous and unbroken bearing outer surface, and having a wall portion extending directly over the tapered shaft which is thinner than the remainder of the bearing wall, wherein the wall is thin to permit piercing thereof for the purpose of removing the bearing head from the tapered shaft.

Claim 3

The prosthetic joint of claim 1 wherein an inner surface of the thinner wall portion of the bearing head is spaced from an outer end of the tapered shaft when the bearing head is mounted on the tapered shaft.

Claim 4

The prosthetic joint of claim 1 wherein the thinner wall portion of the bearing head defines a central area of the bearing outer surface.

Claim 5

A kit comprising the prosthetic joint of claim 1, and further comprising: puller means for pulling the bearing head away from the tapered shaft by piercing the thin wall thereof.

Claim 6

The kit of claim 4 wherein the outer surface of the bearing head defines an annular shoulder portion adjacent and about the bore therein, and the puller means engages the annular shoulder portion of the bearing head and has means associated therewith for engaging and then piercing through the thinner wall portion of the bearing head to engage the tapered shaft and urge the bearing head away from the tapered shaft.

Claim 7

In a kit for use in the replacement of a bearing head of a modular prosthetic joint of the type wherein the bearing head has a bore therein and an annular shoulder adjacent to and about the bore, and wherein the bore frictionally mates with a tapered shaft of a stem portion of the joint, with the tapered shaft having a longitudinal axis and an outer end, the improvement which comprises: forming a portion of the bearing head which extends over the tapered shaft of relatively thin material; a puller body having a plurality of leg portions adapted to engage the annular shoulder portion of the bearing head along a plane generally normal to the longitudinal axis of the tapered shaft; and means associated with the puller body for piercing through that portion of the bearing head of relatively thin material to engage the tapered shaft and urge the bearing head away from the tapered shaft, the piercing means being longitudinally movably mounted with respect to the puller body and aligned to move into engagement with that portion of the bearing head of relatively thin material, through such material and into engagement with the outer end of the tapered shaft.

Claim 8

In a kit for use in the replacement of a bearing head of a modular prosthetic joint of the type wherein the bearing head has a bore therein and an annular shoulder adjacent to and about the bore, and wherein the bore frictionally mates with a tapered shaft of a stem portion of the joint, with the tapered shaft having a longitudinal axis and an outer end, the improvement which comprises: forming a portion of the bearing head which extends over the tapered shaft of relatively thin material; a puller body having a plurality of leg portions adapted to engage the annular shoulder portion of the bearing head along a plane generally normal to the longitudinal axis of the tapered shaft; and means associated with the puller body for piercing through that portion of the bearing head of relatively thin material to engage the tapered shaft and urge the bearing head away from the tapered shaft, the piercing means being longitudinally movably mounted with respect to the puller body and aligned to move into engagement with that portion of the bearing head of relatively thin material, through such material and into engagement with the outer end of the tapered shaft.

Claim 9

The kit of claim 6 wherein the piercing means includes a rod which is threadably mounted with respect to the puller body and which has a pointed end thereof aligned to axially engage the bearing head and outer end of the tapered shaft.

Claim 12

The method of claim 8, and further comprising the steps of: withdrawing the rod member from its pierced relation with respect to the bearing head; and discarding the pierced bearing head.

Claim 15

A kit including a prosthetic joint and means for separation of components thereof, the kit comprising: (a) a stem for affixing substantially within a bone, the stem having a tapered shaft at one end thereof with the tapered shaft being the only portion of the stem extending from the bone and the tapered shaft having an end surface at its outermost end; (b) a bearing head having a bearing side and a mounting side with a bore in the mounting side adapted for frictional engagement with the tapered shaft, the bearing head having a shoulder portion on its mounting side which extends about the bore and which is closely spaced from the bone, and the bearing head defining a generally spherical bearing outer surface on its bearing side, with a central portion on the bearing outer surface extending over the outermost end of the tapered shaft; and (c) a bearing head puller which includes: (1) a puller body having a leg portion adapted to engage the shoulder portion of the bearing head between the shoulder portion and adjacent bone and having a central body section aligned to extend over the central portion of the bearing outer surface, (2) a rod member mounted with respect to the central body section of the puller body for movement toward the bearing head, the rod member aligned to move into engagement with the central portion of the bearing outer surface of the bearing head, pierce through that central portion and move into engagement with the end surface of the tapered shaft, and (3) means for urging the rod member toward and through the central portion of the bearing outer surface of the bearing head and against the end surface of the tapered shaft.

Claim 16

A kit including a prosthetic joint and means for separation of components thereof, the kit comprising: (a) a stem for affixing substantially within a bone, the stem having a tapered shaft at one end thereof with the tapered shaft being the only portion of the stem extending from the bone and the tapered shaft having an end surface at its outermost end; (b) a bearing head having a bearing side and a mounting side with a bore in the mounting side adapted for frictional engagement with the tapered shaft, the bearing head having a shoulder portion on its mounting side which extends about the bore and which is closely spaced from the bone, and the bearing head defining a generally spherical bearing outer surface on its bearing side, with a central portion on the bearing outer surface extending over the outermost end of the tapered shaft; and (c) a bearing head puller which includes: (1) a puller body having a leg portion adapted to engage the shoulder portion of the bearing head between the shoulder portion and adjacent bone and having a central body section aligned to extend over the central portion of the bearing outer surface, (2) a rod member mounted with respect to the central body section of the puller body for movement toward the bearing head, the rod member aligned to move into engagement with the central portion of the bearing outer surface of the bearing head, pierce through that central portion and move into engagement with the end surface of the tapered shaft, and (3) means for urging the rod member toward and through the central portion of the bearing outer surface of the bearing head and against the end surface of the tapered shaft.