US4318191A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Compliant head femoral endoprosthesis
Assignee: Massachusetts Institute of Technology
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Filing: 1980-08-13
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Granted: 1982-03-09
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Expires: 2000-08-13
Abstract
Abstract An endoprosthesis is provided which includes a femoral head construction having a compliant metal shell attached thereto. The shell fits into the acetabulum of the hip joint and is spaced apart from a spherical surface of the construction a sufficient distance to permit the shell to flex without exceeding its elastic limit.
Inventors
- 👤 Slobodan Tepic
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:41
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2/32; A61F2/36; A61F2/3609; A61F2/30721; A61F2/30723; A61F2/3601; A61F2002/30001; A61F2002/30316; A61F2002/30535; A61F2002/30563; A61F2002/30565; A61F2002/30581; A61F2002/30593; A61F2002/3611; A61F2002/3621; A61F2002/3625; A61F2002/3631
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
99 words
An endoprosthesis comprising a stem adapted to be secured to a thigh bone, a femoral head construction secured to said stem and adapted to fit into the acetabulum of a hip joint, said femoral head construction comprising an upper femoral head portion having an outside generally spherical shape, a compliant metal shell secured to and spaced away from said upper femoral head portion in order to cover said generally spherical surface, said compliant shell being spaced apart from said spherical surface at a distance to permit said compliant shell to flex within said acetabulum without exceeding its elastic limit.
Claim 2
Dependent Claim
99 words
An endoprosthesis comprising a stem adapted to be secured to a thigh bone, a femoral head construction secured to said stem and adapted to fit into the acetabulum of a hip joint, said femoral head construction comprising an upper femoral head portion having an outside generally spherical shape, a compliant metal shell secured to and spaced away from said upper femoral head portion in order to cover said generally spherical surface, said compliant shell being spaced apart from said spherical surface at a distance to permit said compliant shell to flex within said acetabulum without exceeding its elastic limit.
Claim 3
Dependent Claim
22 words
The prosthesis of claim 1 wherein a viscoelastic material is positioned within the space between said compliant shell and said spherical surface.
Claim 4
Dependent Claim
35 words
The prosthesis of claim 1 wherein said upper femoral head portion is hollow and a viscous liquid is positioned within said hollow portion and within the space between said compliant shell and said spherical surface.
References Cited (Backward Citations)
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Cited
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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) | 1985-03-08 | 1985-09-07 | 1986-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-03-08 | 1989-09-07 | 1990-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-03-08 | 1993-09-07 | 1994-03-09 | $7700.00 | Window Closed / Lapsed |