US3798679A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Joint prostheses
Assignee: Individual
•
Filing: 1971-07-09
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Granted: 1974-03-26
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Expires: 1991-07-09
Abstract
Abstract Joint prostheses are disclosed which include a substantially smooth male portion (e.g. a femoral cap or a trochlea) and a mated female portion (e.g. a tibial plateau or an olecrenon). Prosthesis forms may be prepared by forming initially the male portion, pressing the male portion into molding material to initiate the formation of the female portion, and passing the portions through flexion in contact to form flexion surfaces on the female portion. The components of the present prostheses are suitable as several joint prostheses, such as knee, elbow, ankle, shoulder, finger and toe joints, including a first component of an inert metal alloy and a second component of molded plastic having at least one flexion surface and upwardly extending guiding-bearing surfaces surrounding same. Prosthesis forms may be prepared similarly, including the formation of a flexion surface by passing the joint through flexion. A knee prosthesis is described including a substantially smooth femoral cap in combination with a mated tibial plateau. The tibial plateau is formed to include means to lock the femoral cap and tibial plateau in extension and means to constantly change the instantaneous centers of rotation during flexion. The tibial plateau surfaces are such that there is maximal surface contact at extension between the tibial plateau and the femoral cap, and during flexion there is substantial surface contact. An elbow prosthesis is described including a substantially smooth humeral cap in combination with a mated ulnar component. The ulnar component is formed to include mating surfaces corresponding to the olecrenon and coronoid processes, as well as the radial head if desired. During flexion of the elbow joint, there is substantial surface contact between the humeral cap and the surface of the ulnar component.
Inventors
- 👤 Ewald Frederick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:01
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2/38; A61F2/3804
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
171 words
A prosthesis for a human joint for replacement of amputated articulating surfaces thereof and adapted for articulating movement between extreme positions of extension and flexion comprising, a smooth rounded male portion having a continuous convex flexion surface defining a compression receiving area, a female portion shaped to provide a continuous curved elongated concave surface including a flexion surface at the bottom of said concavity and guide bearing surfaces laterally thereof adapted to receive said male portion and defining a compression receiving area at the flexion surface of said female portion, said respective compression receiving areas being in contact only at a substantial point of contact at which the principal forces across said joint are concentrated, said male portion being free to rotate on and slide along the flexiOn and guide bearing surfaces of said female portion, and the respective positions and curvatures of said flexion surfaces comprising means responsive to the combined vector forces surrounding said joint after said amputation for continuously longitudinally shifting said substantial point of contact during flexion.
Claim 2
Dependent Claim
171 words
A prosthesis for a human joint for replacement of amputated articulating surfaces thereof and adapted for articulating movement between extreme positions of extension and flexion comprising, a smooth rounded male portion having a continuous convex flexion surface defining a compression receiving area, a female portion shaped to provide a continuous curved elongated concave surface including a flexion surface at the bottom of said concavity and guide bearing surfaces laterally thereof adapted to receive said male portion and defining a compression receiving area at the flexion surface of said female portion, said respective compression receiving areas being in contact only at a substantial point of contact at which the principal forces across said joint are concentrated, said male portion being free to rotate on and slide along the flexiOn and guide bearing surfaces of said female portion, and the respective positions and curvatures of said flexion surfaces comprising means responsive to the combined vector forces surrounding said joint after said amputation for continuously longitudinally shifting said substantial point of contact during flexion.
Claim 3
Dependent Claim
24 words
The prosthesis according to claim 1 further including means comprising an extension surface on said female portion for locking said human joint at extension.
Claim 4
Dependent Claim
107 words
The prosthesis according to claim 2 wherein said human joint is a human knee joint, said male portion is a femoral cap having medial and lateral condyles, said male portion is a mated tibial plateau and further including means responsive to the combined vector forces surrounding said knee joint after said amputation to guide said medial condyle during flexion in a substantially anterior-posterior direction through a curved articular surface of said tibia plateau about a pivot point of contact between said lateral condyle and a pivotal articular surface of said tibial plateau and for forcing fluid therebetween under dynamic fluid conditions to lubricate said maximum compression areas.
Claim 5
Dependent Claim
29 words
The prosthesis according to claim 1 wherein said male portion is constructed of an inert metal alloy and said female portion is constructed of an inert molded high-density plastic.
Claim 6
Dependent Claim
128 words
A knee prosthesis comprising a femoral cap having medial and lateral condyles and a tibial plateau having medial and lateral mating surfaces for mating with said medial and lateral condyles of said femoral cap, wherein both tibial plateau surfaces contain an extension surface for mating at extension with said femoral cap with maximal surface contact and a flexion surface for mating during flexion with said femoral cap with substantial surface contact, said femoral cap further comprises at least one curved bearing surface having a constant or slightly continuously -changing curvature radius for contact with said flexion surface of said tibial plateau, and wherein said flexion surface has a radius of curvature slightly greater than said curvature radius of said curved bearing surface at any given point of contact.
Claim 7
Dependent Claim
128 words
A knee prosthesis comprising a femoral cap having medial and lateral condyles and a tibial plateau having medial and lateral mating surfaces for mating with said medial and lateral condyles of said femoral cap, wherein both tibial plateau surfaces contain an extension surface for mating at extension with said femoral cap with maximal surface contact and a flexion surface for mating during flexion with said femoral cap with substantial surface contact, said femoral cap further comprises at least one curved bearing surface having a constant or slightly continuously -changing curvature radius for contact with said flexion surface of said tibial plateau, and wherein said flexion surface has a radius of curvature slightly greater than said curvature radius of said curved bearing surface at any given point of contact.
Claim 8
Dependent Claim
97 words
A knee prosthesis comprising a femoral cap having medial and lateral condyles and a tibial plateau having medial and lateral mating surfaces for mating with said medial and lateral condyles of said femoral cap, wherein both tibial plateau surfaces contain an extension surface, said extension surface including means for mating at extension with said femoral cap with maximal surface contact and a flexion surface, said flexion surface including means for mating during flexion with said femoral cap with less than maximal but still substantial surface contact, the location of said substantial surface contact continuously shifting during flexion.
Claim 9
Dependent Claim
97 words
A knee prosthesis comprising a femoral cap having medial and lateral condyles and a tibial plateau having medial and lateral mating surfaces for mating with said medial and lateral condyles of said femoral cap, wherein both tibial plateau surfaces contain an extension surface, said extension surface including means for mating at extension with said femoral cap with maximal surface contact and a flexion surface, said flexion surface including means for mating during flexion with said femoral cap with less than maximal but still substantial surface contact, the location of said substantial surface contact continuously shifting during flexion.
Claim 10
Dependent Claim
33 words
The knee prosthesis of claim 6, wherein said maximal surface contact includes contact between the femoral cap and at least 75 percent of said medial and lateral mating surfaces of said tibial plateau.
Claim 11
Dependent Claim
22 words
The knee prosthesis of claim 6, wherein said tibial plateau comprises upwardly extending guiding-bearing surfaces about said medial and lateral mating surfaces.
Claim 12
Dependent Claim
29 words
The knee prosthesis of claim 6, wherein said femoral cap is constructed of an inert metal alloy and said tibial plateau is constructed of an inert molded high-density plastic.
Claim 13
Dependent Claim
117 words
A knee prosthesis comprising a femoral cap having medial and lateral condyles and a tibial plateau having medial and lateral mating surfaces for mating with said medial and lateral condyles of said femoral cap, wherein both tibial plateau surfaces contain an extension surface for mating at extension with said femoral cap with maximal surface contact and a flexion surface for mating during flexion with said femoral cap with substantial surface contact, said prosthesis further includes means to guide said medial condyle during flexion in a substantial anterior -posterior direction through a curved articular surface of said tibiAl plateau about a pivot point of contact between said lateral condyle and a pivotal articular surface of said tibial plateau.
Claim 14
Dependent Claim
117 words
A knee prosthesis comprising a femoral cap having medial and lateral condyles and a tibial plateau having medial and lateral mating surfaces for mating with said medial and lateral condyles of said femoral cap, wherein both tibial plateau surfaces contain an extension surface for mating at extension with said femoral cap with maximal surface contact and a flexion surface for mating during flexion with said femoral cap with substantial surface contact, said prosthesis further includes means to guide said medial condyle during flexion in a substantial anterior -posterior direction through a curved articular surface of said tibiAl plateau about a pivot point of contact between said lateral condyle and a pivotal articular surface of said tibial plateau.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-25 | 1977-09-24 | 1978-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-25 | 1981-09-24 | 1982-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-25 | 1985-09-24 | 1986-03-26 | $7700.00 | Window Closed / Lapsed |