# US 6,217,620 B1 · Reinforcing an orthopedic implant > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,217,620 B1 - Document ID: US6217620B1 - Status: Granted - Kind: B1 - Application number: 09/149,150 - Filed: 1998-09-08 - Granted: 2001-04-17 - Earliest claimed: 1995-09-29 - Inventors: Joon B. Park - Web page: https://patentgrep.com/patent/US6217620B1 ## CPC - A61F 2/30907: {Nets or sleeves applied to surface of prostheses or in cement} - A61B 17/8802: {Equipment for handling bone cement or other fluid fillers} - 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 - 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) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## 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, in the shape of a wire mesh, or in the design of a coil reinforced centralizer. Prior to being implanted, the support structure can be precoated with bone cement or can be prefabricated with a prosthetic device. ## Claims ### Claim 1 A centralizing support structure for placement around the distal end of a prosthesis for counteracting hoop-stress, said support structure comprising: a coil made from a metallic wire adapted to be placed around the distal end of a prosthesis, said distal end of said prosthesis having an apex at which said distal end culminates, said coil being shaped generally to conform to the contours of said prosthesis; and at least two vertical columns enclosing pre-selected sections of said coil, said columns being spaced along the coil and converging radially toward the apex of the distal end of said prosthesis, said columns being made from a bone cement compatible material. ### Claim 2 (depends on 1) A support structure as defined in claim 1, wherein said coil is made from a metallic wire having a diameter of at least about 0.3 millimeters. ### Claim 3 (depends on 1) A support structure as defined in claim 1, wherein said coil is precoated with a bone cement compatible material. ### Claim 4 (depends on 3) A support structure as defined in claim 3, wherein said precoat comprises an acrylic polymer composition containing polymethyl methacrylate. ### Claim 5 (depends on 1) A support structure as defined in claim 1, further comprising a centering pin projecting out from an end of said columns, said centering pin being adapted to matingly engage said prothesis. ### Claim 6 (depends on 1) A support structure as defined in claim 1, wherein said support structure includes four vertical columns. ### Claim 7 (depends on 1) A support structure as defined in claim 1, wherein said coil comprises a wire mesh. ### Claim 8 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 adapted to be placed within a receiving site formed in a bone, said stem having a distal end and a proximal end, said distal end defining an opening; a centralizing support structure located about said distal end of said stem, said support structure comprising a metallic coil configured to surround said distal end of said prosthetic device and at least two vertical columns converging radially towards an apex of said distal end, said vertical columns being spaced along said coil, said support structure further including a centering pin configured to be inserted into said opening defined by said distal end of said prosthetic device. ### Claim 9 (depends on 8) An implant product as defined claim 8, wherein said prosthetic device comprises a hip prosthesis. ### Claim 10 (depends on 8) An implant product as defined in claim 8, further comprising a bone cement compatible coating covering at least said distal end of said stem. ### Claim 11 (depends on 8) An implant product as defined in claim 8, wherein said metallic coil is made from a metal wire having a diameter between about 0.3 millimeters to about 1.0 millimeters. ### Claim 12 (depends on 8) An implant product as defined in claim 8, wherein said coil is coated with a bone cement compatible coating. ### Claim 13 (depends on 8) An implant product as defined in claim 8, wherein said vertical columns are made from a bone cement compatible material. ### Claim 14 (depends on 8) An implant product as defined in claim 8, wherein said stem of said prosthetic device and said metallic coil are coated with an acrylic polymer. ### Claim 15 (depends on 8) An implant product as defined in claim 8, wherein said centering pin is connected to said vertical columns and is positioned where said vertical columns converge. ### Claim 16 A support structure for placement around at least the distal end of a prosthesis for counteracting hoop-stress, said support structure comprising: a coil made from a metallic wire adapted to be placed around the distal end of a prosthetic device, said coil being shaped generally to conform to the contours of said device; a precoat of a bone cement compatible material covering said coil, said precoat having a substantially pore free outer surface for subsequent bonding with a bone cement composition in which said coil is implanted; and at least two vertical columns enclosing preselected sections of said coil, said columns being made from a bone cement compatible material and being spaced at predetermined positions along said coil. ### Claim 17 (depends on 16) A support structure as defined in claim 16, wherein said columns include alignment tabs projecting out from the interior surface of said coil, said tabs adapted to contact and align a corresponding prosthetic device with said support structure. ### Claim 18 (depends on 17) A support structure as defined in claim 17, wherein said alignment tabs have an adjustable length.