# US 7,744,602 B2 · Acetabular shell removal tool

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- Number: US 7,744,602 B2
- Document ID: US7744602B2
- Status: Granted
- Kind: B2
- Application number: 11/046,546
- Filed: 2005-01-28
- Published: 2006-08-31
- Granted: 2010-06-29
- Earliest claimed: 2005-01-28
- Assignees: Steven M. Teeny
- Inventors: Steven M. Teeny; Steven G. Jacobsen
- Web page: https://patentgrep.com/patent/US7744602B2

## CPC

- A61F 2/4609: {of acetabular cups}
- A61F 2002/30387: {Dovetail connection}
- A61F 2002/30471: {connected by a hinged linkage mechanism, e.g. of the single-bar or multi-bar linkage type}
- A61F 2002/30492: {using a locking pin}
- A61F 2002/30505: {spring biased}
- A61F 2002/3054: {about a connection axis or implantation axis for selecting any one of a plurality of radial orientations between two modular parts, e.g. Morse taper connections, at discrete positions, angular positions or continuous positions}
- A61F 2002/4619: {for extraction}
- A61F 2002/4629: {connected to the endoprosthesis or implant via a threaded connection}
- A61F 2220/0025: Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
- A61F 2220/0091: connected by a hinged linkage mechanism, e.g. of the single-bar or multi-bar linkage type
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)

## Abstract

A tool for separating an acetabular shell of a hip prosthesis from the surrounding pelvic bone includes a fixture which attaches to the acetabular shell and has a chisel guide mounted on it. A chisel associated with the chisel guide is curved to conform to the outer periphery of the acetabular shell, and the chisel guide causes the chisel to circumscribe the acetabular shell as the chisel is inserted between the acetabular shell and the pelvis.

## Claims

### Claim 1

A tool for removing the acetabular shell of an artificial hip, said acetabular shell having a semi-spheroidal outer surface and a semi-spheroidal inner surface, said tool comprising:
a. a fixture which attaches to the acetabular shell;
b. a chisel guide mounted on said fixture;
c. a chisel associated with said chisel guide, wherein said chisel guide controls the movement of said chisel such that said chisel substantially circumscribes the outer surface of the acetabular shell when moved;
d. wherein the shell has an opening located in its center and said fixture includes an anchor which is attached to the shell through said opening; and
e. wherein said fixture includes a centering plate which is circular in cross-section with a diameter which is equal to the inner diameter of an intermediate section of the shell and has a central hole which allows said centering plate to be placed over said anchor when said anchor is attached to said shell and moved along said anchor into the shell to center said anchor in said shell.

### Claim 2 (depends on 1)

The tool of claim 1 wherein said chisel is slidably carried by said chisel guide.

### Claim 3 (depends on 1)

The tool of claim 1 wherein said anchor has a seat having self tapping threads and said seat is configured to be inserted into said opening.

### Claim 4 (depends on 1)

The tool of claim 1 wherein said opening is threaded and said anchor has a seat having threads which mate with the threads in said opening.

### Claim 5 (depends on 1)

The tool of claim 1 wherein said anchor and said central hole in said centering plate have mating threads.

### Claim 6 (depends on 1)

The tool of claim 1 wherein the shell has a radially extending edge and said fixture includes a cylindrical locking plate having a central opening which allows said locking plate to be placed on said anchor, and a peripheral base which rests on the edge of the shell.

### Claim 7 (depends on 6)

The tool of claim 6 wherein said locking plate includes a locking mechanism which holds said locking plate on said anchor when said peripheral base is resting on the edge of the shell.

### Claim 8 (depends on 7)

The tool of claim 7 wherein said chisel guide releasable attaches to said locking plate.

### Claim 9 (depends on 8)

The tool of claim 8 wherein said chisel guide includes an arcuate track which conforms to the outer surface of the shell.

### Claim 10 (depends on 9)

The tool of claim 9 wherein said chisel has a rail which interfits with said track in said chisel guide.

### Claim 11 (depends on 10)

The tool of claim 10 wherein said chisel is arcuate along a longitudinal axis and has an inner surface with substantially the same shape as the outer surface of the shell.

### Claim 12 (depends on 11)

The tool of claim 11 wherein said inner surface is arcuate having a radius which is substantially equal to the radius of the outer surface of the shell.

### Claim 13 (depends on 11)

The tool of claim 11 wherein the chisel includes an impact pad which allows the chisel to be moved in either direction by striking the impact pad with a mallet.