US4944761A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Blade-like stem for a femoral head prosthesis
Assignee: Sulzer AG
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Filing: 1989-12-08
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Granted: 1990-07-31
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Expires: 2009-12-08
Abstract
Abstract The stem of the femoral head prothesis has a distal zone of cylindrical cross-section and a proximal zone of rectangular cross section which extends from the distal zone. The sides of the stem in the proximal zone are plane with outstanding parallel ribs which can be driven into the spongy tissue of a femur bone. The ribs on the anterior side of the stem are of a lower height than the ribs on the posterior side. The outermost ribs on each side provide for a resilient four-point bearing on the hard cortical shell of the fem>r bone. A pair of trochanter wings are provided on the narrow lateral side to penetrate into the cortical shell of the femur bone in order to preclude rotation of the stem within the bone.
Inventors
- 👤 Karl-Gerhart Stuhmer
- 👤 Rudolf Koch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 05:11
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2/32; A61F2/36; A61B; A61B17/00; A61B17/16; A61B17/1659; A61F2/3662; A61F2/367; A61F2/3676; A61F2002/30001; A61F2002/30108; A61F2002/3011; A61F2002/30112; A61F2002/30113; A61F2002/30138; A61F2002/30153; A61F2002/30316; A61F2002/30535; A61F2002/30594; A61F2/30767; A61F2/30771; A61F2002/30841; A61F2002/30845; A61F2002/30878; A61F2002/30879; A61F2002/30884; A61F2002/3678; A61F2002/368; A61F2002/369; A61F2/46; A61F2/4603; A61F2002/4619; A61F2230/00; A61F2230/0002; A61F2230/0004; A61F2230/0006; A61F2230/0017; A61F2230/0019
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
159 words
A blade-like stem for a femoral head prosthesis having a distal zone of cylindrical cross-section, said zone including a plurality of longitudinal slots; a proximal zone of rectangular cross-section extending from said distal zone along a longitudinal axis, said proximal zone widening continuously in a medial direction and a lateral direction longitudinally thereof and having two plane sides; a plurality of sharp-edged ribs extending from each said plane side of said proximal zone in parallel to said longitudinal axis, at least a majority of said ribs on a posterior one of said sides being of greater height than said ribs on an anterior one of said sides, said ribs on said anterior side being of equal height to each other; and a prosthesis neck extending from said proximal zone, said neck being disposed on an axis in a plane forming an angle on said anterior side of said proximal zone with a longitudinal center plane of said proximal zone.
Claim 2
Dependent Claim
159 words
A blade-like stem for a femoral head prosthesis having a distal zone of cylindrical cross-section, said zone including a plurality of longitudinal slots; a proximal zone of rectangular cross-section extending from said distal zone along a longitudinal axis, said proximal zone widening continuously in a medial direction and a lateral direction longitudinally thereof and having two plane sides; a plurality of sharp-edged ribs extending from each said plane side of said proximal zone in parallel to said longitudinal axis, at least a majority of said ribs on a posterior one of said sides being of greater height than said ribs on an anterior one of said sides, said ribs on said anterior side being of equal height to each other; and a prosthesis neck extending from said proximal zone, said neck being disposed on an axis in a plane forming an angle on said anterior side of said proximal zone with a longitudinal center plane of said proximal zone.
Claim 3
Dependent Claim
22 words
A stem as set forth in claim 1 wherein each said rib decreases in height in stepwise manner in a distal direction.
Claim 4
Dependent Claim
59 words
A stem as set forth in claim 2 which further comprises a pair of trochanter wings, each said wing extending laterally from a respective one of said sides of said proximal zone and longitudinally from a point of intersection of said neck axis and a lateral narrow side of said proximal zone, each said wing having a sharp edge.
Claim 5
Dependent Claim
59 words
A stem as set forth in claim 1 which further comprises a pair of trochanter wings, each said wing extending laterally from a respective one of said sides of said proximal zone and longitudinally from a point of intersection of said neck axis and a lateral narrow side of said proximal zone, each said wing having a sharp edge.
Claim 6
Dependent Claim
138 words
A stem for a femoral head prosthesis having a distal zone; a proximal zone of rectangular cross-section extending from said distal zone along a longitudinal axis, said proximal zone widening in a medial direction and a lateral direction longitudinally thereof and having a plane posterior side and a plane anterior side; and a plurality of sharp-edged ribs extending from each said side in parallel to said axis for implanting in spongy tissue of a femur, said ribs on said anterior side being of less height than said ribs on said posterior side, the outermost ribs on each said side being sized to bear on a hard cortical shell of the femur bone to define a resilient four point bearing on the cortical shell with the innermost ribs disposed within the spongy tissue and spaced from the cortical shell.
Claim 7
Dependent Claim
138 words
A stem for a femoral head prosthesis having a distal zone; a proximal zone of rectangular cross-section extending from said distal zone along a longitudinal axis, said proximal zone widening in a medial direction and a lateral direction longitudinally thereof and having a plane posterior side and a plane anterior side; and a plurality of sharp-edged ribs extending from each said side in parallel to said axis for implanting in spongy tissue of a femur, said ribs on said anterior side being of less height than said ribs on said posterior side, the outermost ribs on each said side being sized to bear on a hard cortical shell of the femur bone to define a resilient four point bearing on the cortical shell with the innermost ribs disposed within the spongy tissue and spaced from the cortical shell.
Claim 8
Dependent Claim
31 words
A stem as set forth in claim 5 which further comprises a pair of trochanter wings, each wing extending laterally from a respective one of said sides of said proximal zone.
Claim 9
Dependent Claim
48 words
A stem as set forth in claim 5 further comprises a prosthesis neck extending from said proximal zone, said neck being disposed on an axis in a plane forming an angle on said anterior side of said proximal zone with a longitudinal center plane of said proximal zone.
Claim 10
Dependent Claim
59 words
A stem as set forth in claim 7 which further comprises a pair of trochanter wings, each said wing extending laterally from a respective one of said sides of said proximal zone an longitudinally from a point of intersection of said neck axis and a lateral, narrow side of said proximal zone, each said wing having a sharp edge.
Claim 11
Dependent Claim
16 words
A stem as set forth in claim 7 wherein said angle is from 5° to 15°.
Claim 12
Dependent Claim
21 words
A stem as set forth in claim 5 wherein each rib decreases in height in stepwise manner in a distal direction.
Claim 13
Dependent Claim
31 words
A stem as set forth in claim 5 wherein said distal zone is of cylindrical cross-section and has a plurality of longitudinal slots therein to impart resilience to said distal zone.
Claim 14
Dependent Claim
16 words
A stem as set forth in claim 5 wherein said sides are parallel to each other.
References Cited (Backward Citations)
US2719522A
Cited
DE2627569A1
Cited
US4068324A
Cited
US4695283A
Cited
EP0093869A1
Cited
FR2549718A1
Cited
EP0135755A1
Cited
US4728334A
Cited
US4661112A
Cited
EP0169976A1
Cited
FR2573648A1
Cited
EP0222236A1
Cited
DE3609119A1
Cited
FR2602672A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-30 | 1994-01-29 | 1994-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-30 | 1998-01-29 | 1998-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-30 | 2002-01-29 | 2002-07-31 | $7700.00 | Window Closed / Lapsed |