US8764844B2
Active / In Force
US
⏱️ 2.0 years remaining
Joint prosthesis
Assignee: TJ Smith and Nephew Ltd
•
Filing: 2008-10-22
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Granted: 2014-07-01
•
Expires: 2028-10-22
Abstract
Abstract An implant stem ( 1, 2 ) for implantation in a femur, comprising: a base portion ( 3 ) disposed at the proximal end ( 4 ) of the stem and a stem portion ( 5 ) extending to the distal end ( 6 ) of the stem, wherein the base portion ( 3 ) has an engagement means ( 7 ) for engaging, in use, with the resected end of the femur. An implant comprising such a stem ( 1, 2 ) and a head. A method for implanting such implants in a femur.
Inventors
- 👤 Derek James Wallace McMinn
- 👤 Thomas Burton Pynsent
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 20:03
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/28; A61F2/30; A61F2/32; A61F2/36; A61F2/3601; A61F2/3603; A61F2002/2825; A61F2002/2828; A61F2002/30001; A61F2002/30316; A61F2002/30329; A61F2002/30331; A61F2002/30332; A61F2/30767; A61F2002/30769; A61F2/30771; A61F2002/30878; A61F2002/30884; A61F2/3609; A61F2002/3625; A61F2002/3631; A61F2002/3654; A61F2220/00; A61F2220/0025; A61F2220/0033; A61F2310/00; A61F2310/00389; A61F2310/00592; A61F2310/00796
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
313 words
An implant for implantation in a femur, comprising: an implant stem comprising: a base portion disposed at a proximal end of the stem and a stem portion extending to a distal end of the stem, wherein the base portion has an engagement means for engaging a resected head of the femur and defining a distally-facing bone engagement surface structured for engagement with the resected head of the femur to thereby provide the implant with a single stop point to limit insertion of the stem portion into the resected head of the femur; and a tapered portion having an external tapered surface of conical or substantially conical form, said tapered surface extending from said stem portion and terminating at said distally-facing bone engagement surface such that said bone engagement surface defines a lip extending beyond said tapered surface, and wherein said tapered surface of said tapered portion is discontinuous with said distally-facing bone engagement surface of said engagement means so as to define a surface discontinuity; and a modular femoral head; and wherein said bone engagement surface defining said single stop point and said lip is defined by said implant stem and not by said modular femoral head; wherein said modular femoral head is releasably attached to said implant stem by a connector extending from said base portion of said implant stem; wherein said base portion of said implant stem does not include any portion extending distally beyond said distally-facing bone engagement surface defined by said lip, and said modular femoral head extending distally beyond said lip when attached to said implant stem; and wherein said modular femoral head is detached from said implant stem during said engagement of said bone engagement surface with the resected head of the femur to thereby provide an indication of proper engagement of said bone engagement surface defined by said lip with the resected head of the femur.
Claim 2
Dependent Claim
313 words
An implant for implantation in a femur, comprising: an implant stem comprising: a base portion disposed at a proximal end of the stem and a stem portion extending to a distal end of the stem, wherein the base portion has an engagement means for engaging a resected head of the femur and defining a distally-facing bone engagement surface structured for engagement with the resected head of the femur to thereby provide the implant with a single stop point to limit insertion of the stem portion into the resected head of the femur; and a tapered portion having an external tapered surface of conical or substantially conical form, said tapered surface extending from said stem portion and terminating at said distally-facing bone engagement surface such that said bone engagement surface defines a lip extending beyond said tapered surface, and wherein said tapered surface of said tapered portion is discontinuous with said distally-facing bone engagement surface of said engagement means so as to define a surface discontinuity; and a modular femoral head; and wherein said bone engagement surface defining said single stop point and said lip is defined by said implant stem and not by said modular femoral head; wherein said modular femoral head is releasably attached to said implant stem by a connector extending from said base portion of said implant stem; wherein said base portion of said implant stem does not include any portion extending distally beyond said distally-facing bone engagement surface defined by said lip, and said modular femoral head extending distally beyond said lip when attached to said implant stem; and wherein said modular femoral head is detached from said implant stem during said engagement of said bone engagement surface with the resected head of the femur to thereby provide an indication of proper engagement of said bone engagement surface defined by said lip with the resected head of the femur.
Claim 3
Dependent Claim
19 words
An implant according to claim 1 , wherein a proximal area of the stem comprises a bone in-growth surface.
Claim 4
Dependent Claim
16 words
An implant according to claim 1 , wherein the stem portion comprises a bone in-growth surface.
Claim 5
Dependent Claim
17 words
An implant according to claim 1 , wherein the stem portion comprises at least one anti-rotation means.
Claim 6
Dependent Claim
39 words
An implant according to claim 1 , wherein said tapered surface has a maximum diameter that is configured to be substantially the same as an inner diameter of the resected head into which said stem is to be inserted.
Claim 7
Dependent Claim
44 words
An implant according to claim 1 , wherein said connector comprises a projection extending from said base portion of said implant stem, said projection positioned within an opening in said modular femoral head to releasably attach said modular femoral head to said implant stem.
Claim 8
Dependent Claim
18 words
An implant according to claim 6 , wherein said projection is tapered and defines a conical external surface.
Claim 9
Dependent Claim
23 words
An implant according to claim 6 , wherein said projection defines an internally threaded bore configured for threaded engagement with an insertion/removal tool.
Claim 10
Dependent Claim
25 words
An implant according to claim 1 , wherein said modular femoral head is spaced from and does not contact said lip of said implant stem.
Claim 11
Dependent Claim
33 words
An implant according to claim 1 , wherein said indication of proper engagement of said bone engagement surface of said lip with the resected head of the femur comprises a direct visual indication.
Claim 12
Dependent Claim
38 words
An implant according to claim 1 , wherein said external tapered surface of said tapered portion of said implant stem comprises a concave curvature extending from said stem portion to said distally-facing bone engagement surface of said lip.
Claim 13
Dependent Claim
331 words
An implant for implantation in a femur, comprising: an implant stem comprising: a base portion disposed at a proximal end of the stem and a stem portion extending to a distal end of the stem, wherein the base portion has an engagement means for engaging a resected head of the femur and defining a distally-facing bone engagement surface structured for engagement with the resected head of the femur to thereby provide the implant with a single stop point to limit insertion of the stem portion into the resected head of the femur; and a tapered portion from which the stem portion extends, said tapered portion having an external tapered surface which is of conical or substantially conical form, wherein said tapered surface tapers from said base portion towards said stem portion and terminates at said bone engagement surface such that said bone engagement surface defines a lip extending beyond said tapered surface, and wherein the external tapered surface of said tapered portion is discontinuous with the distally-facing bone engagement surface of the engagement means so as to define a surface discontinuity; and a modular femoral head; and wherein said bone engagement surface defining said single stop point and said lip is defined by said implant stem and not by said modular femoral head; wherein said modular femoral head is releasably attached to said implant stem by a connector extending from said base portion of said implant stem; wherein said base portion of said implant stem does not include any portion extending distally beyond said distally-facing bone engagement surface defined by said lip, and said modular femoral head extending distally beyond said lip when attached to said implant stem; and wherein said modular femoral head is detached from said implant stem during said engagement of said bone engagement surface with the resected head of the femur to thereby provide a direct visual indication of proper engagement of said bone engagement surface defined by said lip with the resected head of the femur.
Claim 14
Dependent Claim
331 words
An implant for implantation in a femur, comprising: an implant stem comprising: a base portion disposed at a proximal end of the stem and a stem portion extending to a distal end of the stem, wherein the base portion has an engagement means for engaging a resected head of the femur and defining a distally-facing bone engagement surface structured for engagement with the resected head of the femur to thereby provide the implant with a single stop point to limit insertion of the stem portion into the resected head of the femur; and a tapered portion from which the stem portion extends, said tapered portion having an external tapered surface which is of conical or substantially conical form, wherein said tapered surface tapers from said base portion towards said stem portion and terminates at said bone engagement surface such that said bone engagement surface defines a lip extending beyond said tapered surface, and wherein the external tapered surface of said tapered portion is discontinuous with the distally-facing bone engagement surface of the engagement means so as to define a surface discontinuity; and a modular femoral head; and wherein said bone engagement surface defining said single stop point and said lip is defined by said implant stem and not by said modular femoral head; wherein said modular femoral head is releasably attached to said implant stem by a connector extending from said base portion of said implant stem; wherein said base portion of said implant stem does not include any portion extending distally beyond said distally-facing bone engagement surface defined by said lip, and said modular femoral head extending distally beyond said lip when attached to said implant stem; and wherein said modular femoral head is detached from said implant stem during said engagement of said bone engagement surface with the resected head of the femur to thereby provide a direct visual indication of proper engagement of said bone engagement surface defined by said lip with the resected head of the femur.
Claim 15
Dependent Claim
44 words
An implant according to claim 12 , wherein said connector comprises a projection extending from said base portion of said implant stem, said projection positioned within an opening in said modular femoral head to releasably attach said modular femoral head to said implant stem.
Claim 16
Dependent Claim
18 words
An implant according to claim 13 , wherein said projection is tapered and defines a conical external surface.
Claim 17
Dependent Claim
23 words
An implant according to claim 13 , wherein said projection defines an internally threaded bore configured for threaded engagement with an insertion/removal tool.
Claim 18
Dependent Claim
25 words
An implant according to claim 12 , wherein said modular femoral head is spaced from and does not contact said lip of said implant stem.
Claim 19
Dependent Claim
33 words
An implant according to claim 12 , wherein said indication of proper engagement of said bone engagement surface of said lip with the resected head of the femur further comprises a tactile indication.
Claim 20
Dependent Claim
38 words
An implant according to claim 12 , wherein said external tapered surface of said tapered portion of said implant stem comprises a concave curvature extending from said stem portion to said distally-facing bone engagement surface of said lip.
References Cited (Backward Citations)
US2679245A
Cited
US2650588A
Cited
US2685877A
Cited
US2718228A
Cited
US4944762A
Cited
US4783192A
Cited
JPH04272753A
Cited
WO1993001769A1
Cited
EP0579868A2
Cited
US5571203A
Cited
EP0666069A1
Cited
US5702484A
Cited
US7238208B2
Cited
US6096084A
Cited
US7156879B1
Cited
US20020133234A1
Cited
JP2002330983A
Cited
EP1240879A2
Cited
US20040225367A1
Cited
WO2003051238A1
Cited
JP2005511243A
Cited
GB2388321A
Cited
US20030187514A1
Cited
US7879106B2
Cited
WO2003096938A2
Cited
US20040024468A1
Cited
US20040193275A1
Cited
US20050197712A1
Cited
US20080200991A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2017-06-30 | 2017-12-30 | 2018-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2021-06-30 | 2021-12-30 | 2022-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2025-06-30 | 2025-12-30 | 2026-07-01 | $7700.00 | Window Closed / Lapsed |