Total knee prosthesis with resurfacing and posterior stabilization capability

• US 5,358,527 A
• Filed: 03/20/1992
• Issued: 10/25/1994
• Est. Priority Date: 03/22/1991
• Status: Expired due to Fees

• Current Assignee: Implantology LLC
• Original Assignee: Mark R. Forte
• Inventors: Forte, Mark R.
• Primary Examiner(s): ISABELLA, DAVID J
• Application Number:
  US07/854,225
• Time in Patent Office: 949 Days
• Field of Search: 623/18, 623/20, 623/16, 606/86, 606/87, 606/88
• US Class Current: 623/20.27
• CPC Class Codes: A61F 2/3845 allowing only for single rotation
• CPC Class Codes: A61F 2/385 also provided with condylar bearing surfaces
• CPC Class Codes: A61F 2/3886 for stabilising knees against anterior or lateral dislocations

Abstract

A resurfacing type of total knee prosthesis is disclosed which also provides a posterior stabilization function over the entire range of flexion. The knee prosthesis provides primary or supplementary posterior stabilization of the reconstructed knee joint by means of a unique mechanical cam/follower mechanism, which is integrated within the medial and lateral distal condyles of the femoral component to provide functional compensation for lost, resected or incompetent posterior cruciate ligaments or to work in conjunction with surgically retained viable or questionably viable cruciate ligament structures of the reconstructed knee joint. The invention extends to prostheses including a hinge means that defines a posterior stabilization means separate from that defined by the condyles. One embodiment of the invention extends individually to the posterior stabilizing hinge means.

Claims

1. A total knee prosthesis capable of providing resurfacing to adjacent ends of existing bone structures, as well as total posterior stabilization to a knee joint, comprising:

a) a femoral component including;

i) a medial condyle having an anterior portion, a distal portion and a posterior portion;

ii) a lateral condyle having an anterior portion, a distal portion and a posterior portion;

iii) an anterior patella flange interconnecting the anterior portions of the medial and lateral condyles in parallel, spaced apart relation; and

iv) cam member means integral with said medial and lateral condyles and located outboard thereof, said cam member means having an anteriorly located concave cam member surface and a posteriorly located convex cam member surface;

b) a tibial component including;

i) multi-radius tibias plateau bearing surface means for receiving said medial and lateral condyles for rolling and sliding movement thereon; and

ii) follower member means integral with said bearing surface means for receiving the cam member surfaces of said cam member means for rotational and sliding movement thereon; and

c) the cam member surfaces of said cam member means being in contact with said follower member means for substantially the entire flexion range of the knee,

wherein said tibial plateau bearing surface means includes;

a. a medial multi-radius tibial plateau bearing surface means located inboard of said follower means and having an anterior, central and posterior portion for receiving said medial femoral condyle for rolling and sliding movement thereon;

b. a lateral inboard multi-radius tibial plateau bearing surface means located inboard of said follower means and having an anterior, central and posterior portion for receiving said inboard portion of the lateral femoral condyle for rolling and sliding movement thereon;

c. a medial outboard-located follower member consisting of a convex follower member surface anteriorly and a concave arcuate follower member surface posteriorly for receiving said anterior concave cam member surface and posterior convex cam member surface of the medial cam member means for rolling and sliding movement thereon, said medial concave arcuate follower member surface being connected to the respective posterior portion of the concave arcuate tibial plateau bearing surface means;

d. a lateral outboard-located follower member consisting of a convex follower member surface anteriorly and a concave arcuate follower member surface posteriorly for receiving said anterior concave cam member surface and posterior convex cam member surface of the medial cam member means for rolling and sliding movement thereon, said lateral concave arcuate follower member surface being connected to the respective posterior portion of the concave arcuate tibial plateau bearing surface means; and

e. an interconnecting intercondylar eminence centrally disposed between the medial and lateral multi-radius tibial plateau bearing surface means, said interconnecting eminence being connected to said plateau bearing surface means, and said being removed within the posterior intercondylar portion to provide required clearance for retained anterior and posterior cruciate ligament structures.

2. A total knee prosthesis according to claim 1, wherein said convex cam member integrated within the outboard portion of the medial and lateral distal femoral condyles has a center of curvature being substantially the same as a center of curvature of said respective outboard concave arcuate follower members, of said respective outboard posterior portion of the concave arcuate tibial plateau bearing surface means and of said respective inboard posterior portion of the concave arcuate femoro-tibial plateau bearing surface members means.

3. A total knee prosthesis according to claim 1, wherein said medial and lateral posterior femoral condyles have a radius of curvature substantially the same as a radius of curvature of said respective outboard convex cam members, of said respective outboard concave arcuate follower members, of said respective outboard posterior portion of the concave arcuate tibial plateau bearing surface means, and of said respective inboard posterior portions of the concave arcuate femoro-tibial plateau bearing surface member means.

4. A total knee prosthesis according to claim 1, wherein said medial and lateral posterior femoral condyles have a center of curvature that is displaced anteriorly by some small distance relative to a center of curvature of said medial and lateral outboard convex cam member means, of said respective outboard concave arcuate follower member means, of said respective outboard posterior portion of the concave arcuate tibial plateau bearing surface means and of said respective inboard posterior portions of the concave arcuate femoro-tibial plateau bearing surface member means.

5. A total knee prosthesis according to claim 1, wherein said tibial component includes a tibial plateau bearing component containing medial and lateral multi-radius femoro-tibial plateau bearing surface means, an interconnecting centrally disposed eminence and outboard-located medial and lateral follower member means, and a tibial base component connected to an underside of said tibial plateau bearing component by means of a continuous and wedging peripheral and central engaging dovetail structures and preloaded and secured with a screw thread locking means which is installed anteriorly.

6. A total knee prosthesis capable of providing resurfacing to adjacent ends of existing bone structures, as well as to a posterior stabilization to a knee joint, comprising:

a) a femoral component including;

i) a medial condyle having an anterior portion, a distal portion and a posterior portion;

ii) a lateral condyle having an anterior portion, a distal portion and a posterior portion;

iii) an anterior patella flange interconnecting the anterior portions of the medial and lateral condyles in parallel, spaced apart relation; and

iv) cam member means integral with said medial and lateral condyles and located outboard thereof, said cam member means having an anteriorly located concave cam member surface and a posteriorly located convex cam member surface;

b) a tibial component including;

i) multi-radius tibial plateau bearing surface means for receiving said medial and lateral condyles for rolling and sliding movement thereon; and

ii) follower member means integral with said bearing surfaces for receiving the cam surfaces of said cam member means for rotational and sliding movement thereon; and

c) said convex cam member surface being in sliding contact with said follower member means to provide posterior rollback of said condyles on said tibial plateau bearing surface means during flexion, starting at approximately maximum normal hyperextension of flexion, and being completed at an angle less than approximately 40°

of flexion,

wherein said tibial plateau bearing surface means includes;

a. a medial multi-radius tibial plateau bearing surface means located inboard of said follower means and having an anterior, central and posterior portion for receiving said medial femoral condyle for rolling and sliding movement thereon;

b. a lateral inboard multi-radius tibial plateau bearing surface means located inboard of said follower means and having an anterior, central and posterior portion for receiving said inboard portion of the lateral femoral condyle for rolling and sliding movement thereon;

c. a medial outboard-located follower member consisting of a convex follower member surface anteriorly and a concave arcuate follower member surface posteriorly for receiving said anterior concave cam member surface and posterior convex cam member surface of the medial cam member means for rolling and sliding movement thereon, said medial concave arcuate follower member surface being connected to a respective posterior portion of the concave arcuate tibial plateau bearing surface means;

d. a lateral outboard-located follower member consisting of a convex follower member surface anteriorly and a concave arcuate follower member surface posteriorly for receiving said anterior concave cam member surface and posterior convex cam member surface of the medial cam member means for rolling and sliding movement thereon, said lateral concave arcuate follower member surface being connected to the respective posterior portion of the concave arcuate tibial plateau bearing surface means; and

e. an interconnecting intercondylar eminence centrally disposed between the medial and lateral multi-radius tibial plateau bearing surface means, said interconnecting eminence being connected to said plateau bearing surface means, and said eminence being removed within a posterior intercondylar portion to provide required clearance for retained anterior and posterior cruciate ligament structures.

7. A total knee prosthesis according to claim 6, wherein said convex cam member integrated within the outboard portion of the medial and lateral distal femoral condyles has a center of curvature being substantially the same as the center of curvature of said respective outboard concave arcuate follower members, of said respective outboard posterior portion of the concave arcuate tibial plateau bearing surface member means and of said respective inboard posterior portion of the concave arcuate femoro-tibial plateau bearing surface members means.

8. A total knee prosthesis according to claim 6, wherein said medial and lateral posterior femoral condyles have a radius of curvature substantially the same as the radius of curvature of said respective outboard convex cam members, of said respective outboard concave arcuate follower members, of said respective outboard posterior portion of the concave arcuate tibial plateau bearing surface means, and of said respective inboard posterior portions of the concave arcuate femoro-tibial plateau bearing surface member means.

9. A total knee prosthesis according to claim 6, wherein said medial and lateral posterior femoral condyles have a center of curvature that is displaced anteriorly by some small distance relative to a center of curvature of said medial and lateral outboard convex cam member means, of said respective outboard concave arcuate follower member means, of said respective outboard posterior portion of the concave arcuate tibial plateau bearing surface means and of said respective inboard posterior portions of the concave arcuate femoro-tibial plateau bearing surface member means.

10. A total knee prosthesis capable of providing resurfacing to adjacent ends of existing bone structures, as well as total posterior stabilization to a knee joint, comprising:

a) a femoral component including;

i) a medial condyle having an anterior portion, a distal portion and a posterior portion;

ii) a lateral condyle having an anterior portion, a distal portion and a posterior portion;

iii) an anterior patella flange interconnecting the anterior portions of the medial and lateral condyles in parallel, spaced apart relation; and

iv) cam member means integral with said medial and lateral condyles and located outboard thereof, said cam member means having an anteriorly located concave cam member surface and a posteriorly located convex cam member surface;

b) a tibial component including;

i) multi-radius tibial plateau bearing surface means for receiving said medial and lateral condyles for rolling and sliding movement thereon; and

ii) follower member means integral with said bearing surfaces for receiving the cam surfaces of said cam member means for rotational and sliding movement thereon; and

c) said convex cam member surface being in sliding contact with said follower member means to provide posterior rollback of said condyles on said tibial plateau bearing surface means during flexion, starting at approximately maximum normal hyperextension of flexion, and being completed at an angle less than approximately 40°

of flexion,

wherein said tibial component includes a tibial plateau bearing component containing medial and lateral multi-radius femoro-tibial plateau bearing surface means, an interconnecting centrally disposed eminence and outboard-located medial and lateral follower member means, and a tibial base component connected to an underside of said tibial plateau bearing component by means of a continuous and wedging peripheral and central engaging dovetail structures and preloaded and secured with a screw thread locking means which is installed anteriorly.

11. A total knee prosthesis capable of providing resurfacing to adjacent ends of existing bone structures, as well as total posterior stabilization to a knee joint, comprising:

a) a femoral component including;

i) a medial condyle having an anterior portion, a distal portion and a posterior portion;

ii) a lateral condyle having an anterior portion, a distal portion and a posterior portion;

iii) an anterior patella flange interconnecting the anterior portions of the medial and lateral condyles in parallel, spaced apart relation; and

iv) a cam member means integral with said medial and lateral condyles and located outboard thereof, said cam member means having an anteriorly located concave cam member surface and a posteriorly located convex cam member surface;

b) a tibial component including;

i) multi-radius tibial plateau bearing surface means for receiving said medial and lateral condyles for rolling and sliding movement thereon; and

ii) follower member means integral with said bearing surfaces for receiving the cam member surfaces of said cam member means for rotational and sliding movement thereon; and

c) said convex cam surface being in congruent contact with said follower member means from approximately the end of posterior rollback to full flexion,

wherein said tibial plateau bearing surface means includes;

a. a medial multi-radius tibial plateau bearing surface means located inboard of said follower means and having an anterior, central and posterior portion for receiving said medial femoral condyle for rolling and sliding movement thereon;

b. a lateral inboard multi-radius tibial plateau bearing surface means located inboard of said follower means and having an anterior, central and posterior portion for receiving said inboard portion of the lateral femoral condyle for rolling and sliding movement thereon;

c. a medial outboard-located follower member consisting of a convex follower member surface anteriorly and a concave arcuate follower member surface posteriorly for receiving said anterior concave cam member surface and posterior convex cam member surface of the medial cam member means for rolling and sliding movement thereon, said medial concave arcuate follower member surface being connected to the respective posterior portion of the concave arcuate tibial plateau bearing surface means;

d. a lateral outboard-located follower member consisting of a convex follower member surface anteriorly and a concave arcuate follower member surface posteriorly for receiving said anterior concave cam member surface and posterior convex cam member surface of the medial cam member means for rolling and sliding movement thereon, said lateral concave arcuate follower member surface being connected to the respective posterior portion of the concave arcuate tibial plateau bearing surface means; and

e. an interconnecting intercondylar eminence centrally disposed between the medial and lateral multi-radius tibial plateau bearing surface means, said interconnecting eminence being connected to said plateau bearing surface means, and said eminence being removed within a posterior intercondylar portion to provide required clearance for retained anterior and posterior cruciate ligament structures.

12. A total knee prosthesis according to claim 11, wherein said convex cam member integrated within the outboard portion of the medial and lateral distal femoral condyles has a center of curvature being substantially the same as a center of curvature of said respective outboard concave arcuate follower members, of said respective outboard posterior portion of the concave arcuate tibial plateau bearing surface member means and of said respective inboard posterior portion of the concave arcuate femoro-tibial plateau bearing surface members means.

13. A total knee prosthesis according to claim 11, wherein said medial and lateral posterior femoral condyles have a radius of curvature substantially the same as a radius of curvature of said respective outboard convex cam members, of said respective outboard concave arcuate follower members, of said respective outboard posterior portion of the concave arcuate tibial plateau bearing surface means, and of said respective inboard posterior portions of the concave arcuate femoro-tibial plateau bearing surface member means.

14. A total knee prosthesis according to claim 11, wherein said medial and lateral posterior femoral condyles have a center of curvature that is displaced anteriorly by some small distance relative to a center of curvature of said medial and lateral outboard convex cam member means, of said respective outboard concave arcuate follower member means, of said respective outboard posterior portion of the concave arcuate tibial plateau bearing surface means and of said respective inboard posterior portions of the concave arcuate femoro-tibial plateau bearing surface member means.

15. A total knee prosthesis capable of providing resurfacing to adjacent ends of existing bone structures, as well as total posterior stabilization to a knee joint, comprising:

a) a femoral component including;

i) a medial condyle having an anterior portion, a distal portion and a posterior portion;

ii) a lateral condyle having an anterior portion, a distal portion and a posterior portion;

iii) an anterior patella flange interconnecting the anterior portions of the medial and lateral condyles in parallel, spaced apart relation; and

iv) a cam member means integral with said medial and lateral condyles and located outboard thereof, said cam member means having an anteriorly located concave cam member surface and a posteriorly located convex cam member surface;

b) a tibial component including;

i) multi-radius tibial plateau bearing surface means for receiving said medial and lateral condyles for rolling and sliding movement thereon; and

ii) follower member means integral with said bearing surfaces for receiving the cam member surfaces of said cam member means for rotational and sliding movement thereon; and

c) said convex cam surface being in congruent contact with said follower member means from approximately the end of posterior rollback to full flexion,

wherein said tibial component includes a tibial plateau bearing component containing medial and lateral multi-radius femoro-tibial plateau bearing surface means, an interconnecting centrally disposed eminence and outboard-located medial and lateral follower member means, and a tibial base component connected to an underside of said tibial plateau bearing component by means of a continuous and wedging peripheral and central engaging dovetail structures and preloaded and secured with a screw thread locking means which is installed anteriorly.

16. A total knee prosthesis capable of providing resurfacing to adjacent ends of existing bone structures, as well as total posterior stabilization to a knee joint, comprising:

a. a femoral component including;

i. a medial condyle having an anterior condyle portion, an inboard (lateral) distal condyle portion with outboard (medial) cam member means and a posterior condyle portion;

ii. a lateral condyle having an anterior portion, an inboard (medial) distal condyle portion with outboard (lateral) cam member means and a posterior condyle portion;

iii. an anterior patella flange interconnecting the anterior portions of the medial and lateral condyles in parallel, spaced apart relation; and

iv. a cam member means integrated within the outboard portion of the medial and lateral condyles, said cam members having a concave surface portion anteriorly and a convex cam member surface posteriorly;

b. a tibial component including;

i. a medial inboard multi-radius tibial plateau bearing surface means having an anterior, central and posterior portion for receiving said inboard portion of the multi-radius medial femoral condyle for rolling and sliding movement thereon; and

ii. a lateral inboard multi-radius tibial plateau bearing surface means having an anterior, central and posterior portion for receiving said inboard portion of the multi-radius lateral femoral condyle for rolling and sliding movement thereon; and

iii. a medial outboard follower member comprising a convex surface anteriorly and a concave arcuate follower member surface posteriorly for receiving said anterior concave cam surface and posterior convex cam member surface of medial cam member means for rotational and sliding movement thereon, said medial outboard concave arcuate follower member surface means being connected with the respective outboard posterior portion of said inboard and outboard concave arcuate tibial plateau bearing surface means; and

iv. a lateral outboard follower member consisting of a convex surface anteriorly and a concave arcuate follower member surface posteriorly for receiving said anterior concave cam surface and posterior convex cam member surface of lateral cam member means for rotational and sliding movement thereon, said lateral outboard concave arcuate follower member surface means being connected with the respective outboard posterior portion of the concave arcuate tibial plateau bearing surface means; and

v. an interconnecting intercondylar eminence centrally disposed between the medial and lateral inboard multi-radius tibial plateau bearing surface means with said interconnecting eminence being connected to said inboard plateau bearing surface means and said eminence being removed within a posterior intercondylar portion to provide required clearance for retained anterior and posterior cruciate ligament structures;

c. said medial and lateral cam member means being in contact with said respective follower member means from the outset of flexion and said medial and lateral cam member means being in contact with said respective follower member means substantially throughout the entire flexion range of the knee joint, providing uninterrupted posterior (tibia-femur) stabilization.