# US 5,343,877 A · Orthopedic implant and method

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- Number: US 5,343,877 A
- Document ID: US5343877A
- Status: Granted
- Kind: A
- Application number: 07/942,515
- Filed: 1992-09-09
- Granted: 1994-09-06
- Earliest claimed: 1992-09-09
- Assignees: University of Iowa Research Foundation
- Inventors: Joon B. Park
- Web page: https://patentgrep.com/patent/US5343877A

## CPC

- A61B 17/8802: {Equipment for handling bone cement or other fluid fillers}
- A61F 2/30767: {Special external or bone-contacting surface, e.g. coating for improving bone ingrowth}
- A61F 2/4684: {Trial or dummy prostheses}
- A61B 17/8805: {for introducing fluid filler into bone or extracting it (A61B17/7097, A61B17/8833 take precedence)}
- A61F 2/30723: {Plugs or restrictors for sealing a cement-receiving space (tools for inserting plugs A61F2/4614; sealing collars for use during cementing A61B17/8808)}
- A61F 2/32: for the hip
- A61F 2/4607: {of hip femoral endoprostheses}
- A61F 2002/30062: {(bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive}
- A61F 2002/30242: {spherical}
- A61F 2002/30919: {Sleeves}
- A61F 2002/3694: {with longitudinal bores}
- A61F 2002/4631: {the prosthesis being specially adapted for being cemented}
- A61F 2210/0004: bioabsorbable
- A61F 2230/0071: spherical
- A61F 2310/00952: Coating, pre-coating or prosthesis-covering structure made of bone cement, e.g. pre-applied PMMA cement mantle
- Y10S 623/908: Bone
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- 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)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A process of orthopedic implantation of prosthetic devices such as hip and knee joints. The prepared bed of the bone cavity is lined with a pre-coating mixture of bone cement and resorbable particles, followed by filling of the bed with substantially pure bone cement and thereafter the prosthesis is positioned into the fully prepared bed. In this manner, resorbable particles along the lined prepared bed wall are resorbed by the patients body and replaced with new bone tissue ingrowth. As a result bonding of the bone cement to the bone is substantially improved, without weakening the bonding of the implant to the bone cement.

## Claims

### Claim 1

In the process of orthopedic implantation of a prosthetic device in a prepared bed of a bone cavity having a surface readied to receive a prosthesis to be fixed in to said bone cavity by a bone cement composition, the improvement comprising:
forming a pre-coat on substantially all of the surface of the prepared bed of said bone cavity with a mixture of bone cement composition and resorbable particles to form a resorbable particle layer; and wherein said pre-coat has a predetermined thickness; and thereafter,
inserting within the pre-coated bed a substantially pure bone cement composition thereby forming a fully prepared bone cement composition bed; and thereafter,
positioning the prosthesis into the fully prepared bone cement composition bed.

### Claim 2 (depends on 1)

The process of claim 1 wherein the pre-coating mixture of bone cement composition and resorbable particles is from about 5% to about 50% by weight of resorbable particles.

### Claim 3 (depends on 2)

The process of claim 2 wherein the pre-coating composition is from about 25% to about 35% by weight of resorbable particles, wherein said particles are in contact with each other.

### Claim 4 (depends on 3)

The process of claim 3 wherein the resorbable particles are selected from the group consisting of allogeneic whole bone, heterogenic whole bone, demineralized bone, deproteinized bone morphogenic proteins, collagen, gelatin, polysaccharides, polylactic and polyglycolic acid, polyorthoester, calcium phosphate compounds such as tricalcium phosphate hydroxyapatites, and any other biocompatible and resorbable compounds.

### Claim 5 (depends on 4)

The process of claim 4 wherein the resorbable particles are demineralized bone.

### Claim 6 (depends on 1)

The process of claim 1 wherein the thickness of precoat is from about 0.5 mm to about 5 mm.

### Claim 7 (depends on 1)

The process of claim 1 wherein the particle size of resorbable particles is from 0.01 mm to 1.0 mm diameter.

### Claim 8 (depends on 1)

The process of claim 1 wherein the polymer coating and the bone cement composition comprise acrylics.

### Claim 9 (depends on 8)

The process of claim 8 wherein said acrylic comprises polymethylmethacrylate.

### Claim 10 (depends on 1)

The process of claim 1 wherein said pure bone cement composition comprises a mixture of an acrylic polymer, an acrylic monomer, a catalyst, and an accelerator.

### Claim 11 (depends on 10)

The process of claim 10 wherein said acrylic polymer is polymethylmethacrylate and said acrylic monomer is methylmethacrylate.

### Claim 12 (depends on 10)

The process of claim 10 wherein said acrylic polymer is a mixture of polymethylmethacrylate and methylmethacrylate-styrene copolymer and said acrylic monomer is methylmethacrylate.