Total knee joint mold and methods

• US 7,427,296 B2
• Filed: 11/14/2003
• Issued: 09/23/2008
• Est. Priority Date: 11/14/2003
• Status: Active Grant

• Current Assignee: Colorado Orthopedic Academy PC
• Original Assignee: Richard P. Evans
• Inventors: Evans, Richard Parker
• Primary Examiner(s): McDermott; Corrine
• Assistant Examiner(s): Prone; Christopher D
• Application Number:
  US10/714,050
• Publication Number:
  US 20050107885A1
• Time in Patent Office: 1,775 Days
• Field of Search: 623 2014- 2015
• US Class Current: 623/20.14
• CPC Class Codes: A61F 2/30942 for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2002/30672 temporary
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/3069 Revision endoprostheses
• CPC Class Codes: A61F 2002/30878 with non-sharp protrusions, for instance contacting the bone for anchoring, e.g. keels, pegs, pins, posts, shanks, stems, struts
• CPC Class Codes: A61F 2002/30957 using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/4631 the prosthesis being specially adapted for being cemented
• CPC Class Codes: A61F 2310/00353 Bone cement, e.g. polymethylmethacrylate or PMMA
• CPC Class Codes: A61L 2300/406 Antibiotics
• CPC Class Codes: A61L 24/0015 Medicaments; Biocides
• CPC Class Codes: A61L 24/06 obtained by reactions only involving carbon-to-carbon unsaturated bonds A61L24/043, A61L24/046 take precedence
• CPC Class Codes: C08L 33/12 Homopolymers or copolymers of methyl methacrylate
• CPC Class Codes: Y10S 623/901 Method of manufacturing prosthetic device

Abstract

In one embodiment, a method for treating an infected implant area of a knee joint comprises surgically accessing the implant area, and inserting a tibial component into the tibia using an antibiotic-impregnated material. A femoral component is formed that is configured to interact with the tibial component by stable knee joint articulation and motion. The femoral component is formed of an antibiotic-impregnated material using a mold. The femoral component is attached to the femur using an antibiotic-impregnated material, and the tibial component is interfaced with the femoral component to form a stable temporary knee joint capable of reducing the spread of infection while permitting movement of the knee joint.

Claims

1. A method for treating an infected implant area of a knee joint, the method comprising:

surgically accessing the implant area;

inserting a tibial component into the tibia using an antibiotic-impregnated material, wherein the tibial component comprises a tray, a central stem that is inserted into a opening in the tibia and a posterior stabilizing protrusion, and wherein the antibiotic-impregnated material is placed onto the central stem so as to be within the opening in the tibia, wherein placement of the central stem into the opening in the tibia provides stability to the tibial component while attached to the tibia;

while the implant area is surgically accessible, forming a femoral component that is configured to interact with the tibial component, wherein the femoral component is formed of an antibiotic-impregnated material using a mold having a smooth U-shaped back surface with a recess for receiving the antibiotic-impregnated material, and wherein the femoral component comprises a single integral piece that is constructed of two outer surfaces that are spaced apart from each other by a center section having a recess to form a one-piece structure that resurfaces the entire distal femur, wherein the femoral component has a front surface that interfaces with the tibial component and a back surface that interfaces with the femur, wherein the back surface is generally smooth and does not include protrusions such that all areas of the back surface which interface with the femur are without protrusions, and wherein the step of forming the femoral component further comprises pressing the antibiotic-impregnated material into the mold to form the antibiotic-impregnated material in the shape of the femoral component, removing excess antibiotic-impregnated material from the U-Shaped back surface and smoothing the entire back surface of the femoral component using a straight edge which provides the femoral component to be temporarily contacted with the femur, and then removing the mold and permitting the femoral component to harden;

attaching the femoral component to the femur using an antibiotic-impregnated material such that the femoral component does not project into the femur; and

interfacing the tibial component with the femoral component by placing the posterior stabilizing protrusion of the tibial component into the recess of the femoral component, with the two outer surfaces of the femoral component resting on the tray to form a temporary knee joint capable of treating an infection and reducing the spread of infection while permitting movement of the knee joint, with the two outer surfaces, recess and protrusion providing anterior and posterior as well as lateral and medial stability to the knee joint and maintaining the knee joint space, thereby reducing scarring and thus facilitating final implantation.

2. A method as in claim 1, wherein the tibial component comprises a generally smooth articulating element that interfaces with the femoral component to minimize wear on the femoral component.

3. A method as in claim 2, wherein the tibial component is constructed of polyethylene.

4. A method as in claim 1, wherein the step of forming the femoral component further comprises mixing a bone cement in powder form with at least one powdered antibiotic and adding a liquid activating agent to form the antibiotic-impregnated material.

5. A method as in claim 1, wherein the femoral component is formed into the shape of an articulating femoral prosthesis.

6. A method as in claim 1, further comprising re-accessing the implant area after the infection has been treated, removing the femoral and tibial components and inserting a femoral prosthesis and a tibial prosthesis.

7. A method as in claim 1, further comprising removing any infected total knee replacement implants after accessing the implant area.

8. A method as in claim 1, further comprising trimming the femoral component after removing it from the mold.

9. A method for treating an infected implant area of a knee joint, the method comprising:

surgically accessing the implant area;

removing an infected total knee replacement implant;

inserting a tibial component into the tibia using an antibiotic-impregnated material, wherein the tibial component comprises a tray, a central stem that is inserted into a opening in the tibia and a posterior stabilizing protrusion, and wherein the antibiotic-impregnated material is placed onto the central stem so as to be within the opening in the tibia, wherein placement of the central stem into the opening in the tibia provides stability to the tibial component while attached to the tibia;

forming a one-piece femoral component that is configured to interact with the tibial component, wherein the femoral component is formed of an antibiotic-impregnated material using a mold while the implant area is accessible and wherein the femoral component comprises a single integral piece that is constructed of two outer surfaces that are spaced apart from each other and connected by a center section having a recess, wherein the femoral component has a front surface that interfaces with the tibial component and a back surface that interfaces with the femur, wherein the back surface is generally smooth and does not include protrusions such that all areas of the back surface which interface with the femur are without protrusions, and wherein the step of forming the femoral component further comprises pressing the antibiotic-impregnated material into the mold to form the antibiotic-impregnated material in the shape of the femoral component, removing excess antibiotic-impregnated material from a U-Shaped back surface of the mold and smoothing the entire back surface of the femoral component using a straight edge which provides the femoral component to be temporarily contacted with the femur, and then removing the mold and permitting the femoral component to harden;

attaching the femoral component to the femur using an antibiotic-impregnated material with the femoral component resurfacing the entire distal femur and such that the femoral component does not project into the femur; and

interfacing the tibial component with the femoral component by placing the posterior stabilizing protrusion of the tibial component into the recess of the femoral component, with the two outer surfaces resting on the tray to form a temporary knee joint capable of reducing the spread of infection while permitting movement of the knee joint with the two outer surfaces, recess and protrusion providing anterior, posterior as well as lateral and medial stability to the knee joint.

10. A method as in claim 9, wherein the tibial component comprises a generally smooth articulating element that interfaces with the femoral component to minimize wear on the femoral component.

11. A method as in claim 10, wherein the tibial component is constructed of polyethylene.

12. A method as in claim 9, wherein the step of forming the femoral component further comprises mixing a bone cement in powder form with a powdered antibiotic and adding a liquid activating agent to form the antibiotic-impregnated material.

13. A method as in claim 12, wherein the step of forming the femoral component further comprises pressing the antibiotic-impregnated material into the mold to form the antibiotic-impregnated material in the shape of the femoral component and then removing the mold and permitting the femoral component to harden.

14. A method as in claim 9, wherein the femoral component is formed into the shape of an articulating femoral prosthesis.

15. A method as in claim 9, further comprising re-accessing the implant area after the infection has been treated, removing the femoral and tibial components and inserting a permanent revision femoral prosthesis and a tibial prosthesis.

16. A method as in claim 9, further comprising trimming the femoral component after removing it from the mold.