Patent US1943524A successfully refreshed from Google Patents.
US4285070A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Prosthetic device
Assignee: Biomet Inc
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Filing: 1980-06-18
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Granted: 1981-08-25
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Expires: 2000-06-18
Abstract
Abstract A patella prosthesis having a plurality of bearing surfaces designed to provide low-friction interaction throughout the entire range of leg extension and flexure with a metal condylar replacement prosthesis is disclosed. The prosthesis provides a combination of a reinforced patella surface and a femoral prosthetic surface having both a prolonged anterior flange and a central opening for the passage of the cruciate ligaments.
Inventors
- 👤 Robert G. Averill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:53
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2/38; A61F2/3877
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
186 words
A knee joint prosthesis comprising a patella prosthesis for sequential articulation against the condylar surfaces and the surface of the central medially-laterally flat and longitudinally convex groove in an anterior flange bridging said condylar surfaces of a femoral prosthesis having a central opening therein for passage of the cruciate ligaments, said patella prosthesis comprising a substantially flat base, having an outline comprised of two parallel sides and semicircular end portions, one surface of which is adapted for attachment to the resected surface of the natural patella, a bearing insert having a peripheral outline substantially coextensive with said base and having a central laterally extending medially-laterally flat and longitudinally concave ridge portion adapted for sequential tracking within the medially-laterally flat and longitudinally convex groove in the anterior flange of said femoral prosthesis and a pair of shoulders having a shape complementary to the condylar surfaces of said femoral prosthesis for sliding contact with said surfaces during flexion of the knee joint, said central laterally extending medially-laterally flat and longitudinally concave ridge portion and said pair of shoulders thus providing medial and lateral stability to the patellar prosthesis.
Claim 2
Dependent Claim
186 words
A knee joint prosthesis comprising a patella prosthesis for sequential articulation against the condylar surfaces and the surface of the central medially-laterally flat and longitudinally convex groove in an anterior flange bridging said condylar surfaces of a femoral prosthesis having a central opening therein for passage of the cruciate ligaments, said patella prosthesis comprising a substantially flat base, having an outline comprised of two parallel sides and semicircular end portions, one surface of which is adapted for attachment to the resected surface of the natural patella, a bearing insert having a peripheral outline substantially coextensive with said base and having a central laterally extending medially-laterally flat and longitudinally concave ridge portion adapted for sequential tracking within the medially-laterally flat and longitudinally convex groove in the anterior flange of said femoral prosthesis and a pair of shoulders having a shape complementary to the condylar surfaces of said femoral prosthesis for sliding contact with said surfaces during flexion of the knee joint, said central laterally extending medially-laterally flat and longitudinally concave ridge portion and said pair of shoulders thus providing medial and lateral stability to the patellar prosthesis.
Claim 3
Dependent Claim
61 words
A knee joint prosthesis according to claim 1 wherein the surface of the base of the patellar prosthesis for attachment to the resected natural patella is provided with intersecting ridges adapted to be received into corresponding slots cut into the resected patella, said ridges thereby orienting said base on said resected patella and providing stability between said patella and patellar prosthesis.
Claim 4
Dependent Claim
44 words
A knee joint prosthesis according to claim 2 wherein the other surface of said base includes a plurality of projections extending from said surface and adapted to be inserted into corresponding apertures provided in said bearing insert to secure said insert onto said base.
Claim 5
Dependent Claim
54 words
A knee joint prosthesis according to claim 1 wherein the central laterally extending medially-laterally flat and longitudinally concave ridge portion of said bearing insert is dissected at the ends thereof to form two transverse concave bearing surfaces comprising said pair of shoulders adapted for sliding contact with the condylar surfaces of said femoral prosthesis.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-24 | 1985-02-23 | 1985-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-24 | 1989-02-23 | 1989-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-24 | 1993-02-23 | 1993-08-25 | $7700.00 | Window Closed / Lapsed |