# US 5,984,968 A · Reinforcement for an orthopedic implant

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- Number: US 5,984,968 A
- Document ID: US5984968A
- Status: Granted
- Kind: A
- Application number: 08/537,112
- Filed: 1995-09-29
- Granted: 1999-11-16
- Earliest claimed: 1995-09-29
- Inventors: Joon B. Park
- Web page: https://patentgrep.com/patent/US5984968A

## CPC

- A61B 17/8802: {Equipment for handling bone cement or other fluid fillers}
- A61F 2/30907: {Nets or sleeves applied to surface of prostheses or in cement}
- A61F 2/30965: {Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping}
- A61F 2/30724: {Spacers for centering an implant in a bone cavity, e.g. in a cement-receiving cavity}
- A61F 2/30767: {Special external or bone-contacting surface, e.g. coating for improving bone ingrowth}
- A61F 2/3662: {Femoral shafts}
- A61F 2/367: {Proximal or metaphyseal parts of shafts (trochanteric devices connected to said proximal parts A61F2/30739)}
- A61F 2/3676: {Distal or diaphyseal parts of shafts}
- A61F 2002/3021: {frustoconical}
- A61F 2002/30217: {hollow cones, e.g. tubular-like cones}
- A61F 2002/30289: {helically-coiled}
- A61F 2002/30329: {Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements}
- A61F 2002/30451: {soldered or brazed or welded}
- A61F 2002/30909: {Nets}
- A61F 2002/30914: {Details of the mesh structure, e.g. disposition of the woven warp and weft wires}
- A61F 2002/3611: {Heads or epiphyseal parts of femur}
- A61F 2002/3631: {with an integral complete or partial peripheral collar or bearing shoulder at its base}
- A61F 2002/4631: {the prosthesis being specially adapted for being cemented}
- A61F 2220/0025: Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
- A61F 2220/0058: soldered or brazed or welded
- A61F 2230/0067: conical
- A61F 2230/0091: helically-coiled or spirally-coiled, i.e. having a 2-D spiral cross-section
- A61F 2310/00017: Iron- or Fe-based alloys, e.g. stainless steel
- A61F 2310/00023: Titanium or titanium-based alloys, e.g. Ti-Ni alloys
- A61F 2310/00029: Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
- A61F 2310/00101: Molybdenum or Mo-based alloys
- A61F 2310/00401: Coating made of iron, of stainless steel or of other Fe-based alloys
- A61F 2310/00407: Coating made of titanium or of Ti-based alloys
- A61F 2310/00413: Coating made of cobalt or of Co-based alloys
- A61F 2310/00497: Coating made of molybdenum or Mo-based alloys
- A61F 2310/00952: Coating, pre-coating or prosthesis-covering structure made of bone cement, e.g. pre-applied PMMA cement mantle
- 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)

## Abstract

An improved method for reinforcing a prosthetic implant and an implant product are provided. The method includes embedding a support structure in a bed of bone cement surrounding the distal end of a prosthetic device. The support structure counteracts hoop-stress imparted to the implant, decreases creep of the bone cement, and further reinforces the bone cement bed. In various embodiments, the support structure can be in the form of a metal coil or in the shape of a wire mesh. Prior to being implanted, the support structure can be precoated with bone cement or can be prefabricated with a prosthetic device.

## Claims

### Claim 1

An implant product designed to counteract hoop-stress, said implant product comprising:
a prosthetic device for implantation into a prepared area of the body, said prosthetic device including a stem configured to be placed entirely within a receiving site formed in a bone, a distal portion, a middle portion and a proximal portion, said distal proximal portion having a length that is less than half the length of said stem;
a support structure encircling a section of said stem of said prosthetic device, said support structure being made from a wire shaped into a cylindrical configuration generally conforming to the shape of said stem, said support structure having a first end and a second end, said first end of said support structure being placed adjacent to said distal portion of said stem, said support structure extending over said distal portion and terminating adjacent to said middle portion of said stem at said second end; and
a mantle made from a bone cement compatible material, said mantle covering at least the distal portion of said stem of said prosthetic device, said mantle enveloping said support structure, whereby said implant product, when implanted with a bone cement composition in situ, will reinforce said bone cement adjacent said distal portion of said stem for counteracting hoop-stress to which said implant product is exposed.

### Claim 2 (depends on 1)

An implant product as defined in claim 1, wherein said support structure comprises a coil.

### Claim 3 (depends on 1)

An implant product as defined in claim 1, wherein said prosthetic device further comprises a ball attached to said stem, said ball being configured to engage a hip socket.

### Claim 4 (depends on 1)

An implant product as defined in claim 1, wherein said bone cement compatible material comprises an acrylic polymer composition.

### Claim 5 (depends on 1)

An implant product as defined in claim 1, wherein said support structure is made from a metal wire having a diameter between about 0.3 millimeters to about 1.0 millimeters.

### Claim 6 (depends on 1)

An implant product as defined in claim 1, wherein said support structure and said prosthetic device are made from the same material.

### Claim 7 (depends on 1)

An implant product as defined in claim 1, further comprising a precoating covering said support structure, said precoating being made from a bone cement compatible material.

### Claim 8 (depends on 1)

An implant product as defined in claim 1, wherein said wire is made from a material selected from the group consisting of a metal and a polymer.