US4566138A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Prosthetic device with spacers
Assignee: Zimmer Technology Inc
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Filing: 1985-04-24
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Granted: 1986-01-28
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Expires: 2005-04-24
Abstract
Abstract A prosthetic device adapted to be secured to a supporting bone by a thickness of acrylic bone cement. The prosthetic device has an outer surface which includes a plurality of spacers projecting therefrom. The spacers are made of an acrylic material, such as polymethyl methacrylate (PMMA), and are adapted so that when the prosthetic device is positioned against the supporting bone, the spacers provide a uniform space between the bone and prosthetic device, thus uniformly controlling the thickness of cement. The acrylic spacers will repolymerize and bond with the layer of acrylic bone cement. The nature of the bond formed between the new acrylic bone cement and the acrylic spacers should eliminate the stress concentrations at the interface between the spacers and the cement layer, thereby enhancing fixation of the prosthesis.
Inventors
- 👤 Edward L. Lewis
- 👤 Jack E. Parr
- 👤 Mark A. Fox
- 👤 Robert L. Fuson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 06:44
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2/32; A61F2/34; A61F2/30721; A61F2/30724; A61F2002/30001; A61F2002/30316; A61F2002/30329; A61F2002/30331; A61F2002/30332; A61F2002/30405; A61F2002/30451; A61F2002/30621; A61F2002/30649; A61F2002/30662; A61F2/30767; A61F2/30771; A61F2002/30795; A61F2002/30878; A61F2002/30891; A61F2002/30894; A61F2002/3412; A61F2/46; A61F2002/4631; A61F2220/00; A61F2220/0025; A61F2220/0033; A61F2220/0058; A61F2310/00; A61F2310/00005; A61F2310/00353
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
77 words
An acetabular cup to be secured to a supporting bone member by a thickness of acrylic bone cement applied therebetween comprising an inner ultra high molecular weight polyethylene member having a metal outer shell wherein said shell further includes a porous outer surface over at least a portion thereof and said porous surface having a plurality of spacers adhered thereto and projecting a predetermined distance therefrom, said spacers being composed at least in part of acrylic material.
Claim 2
Dependent Claim
77 words
An acetabular cup to be secured to a supporting bone member by a thickness of acrylic bone cement applied therebetween comprising an inner ultra high molecular weight polyethylene member having a metal outer shell wherein said shell further includes a porous outer surface over at least a portion thereof and said porous surface having a plurality of spacers adhered thereto and projecting a predetermined distance therefrom, said spacers being composed at least in part of acrylic material.
Claim 3
Dependent Claim
14 words
The acetabular cup of claim 1, wherein said spacers are composed wholly of acrylic.
Claim 4
Dependent Claim
12 words
The acetabular cup of claim 1, wherein said acrylic is polymethyl methacrylate.
Claim 5
Independent Claim
96 words
A method of preparing a metal-backed acetabular cup having a plurality of acrylic spacers on the outer surface thereof comprising the following steps: (a) providing a porous surface over at least a portion of the metal outer surface of the cup; (b) forming an acrylic material into a suitable shape for spacers; and (c) adhering said spacers to said porous surface at predetermined positions, such that the contacting surface of the spacer melts and flows into the porous surface, and then hardens, forming a secure attachment of the spacer to the porous surface of the cup.
Claim 6
Independent Claim
96 words
A method of preparing a metal-backed acetabular cup having a plurality of acrylic spacers on the outer surface thereof comprising the following steps: (a) providing a porous surface over at least a portion of the metal outer surface of the cup; (b) forming an acrylic material into a suitable shape for spacers; and (c) adhering said spacers to said porous surface at predetermined positions, such that the contacting surface of the spacer melts and flows into the porous surface, and then hardens, forming a secure attachment of the spacer to the porous surface of the cup.
Claim 7
Dependent Claim
22 words
The method of claim 4, wherein the method of adhering includes the step of sonically welding said spacers to the porous surface.
Claim 8
Dependent Claim
23 words
The acetabular cup of claim 1, wherein said spacers are secured to said outer porous surface by means of a sonically welded bond.
Claim 9
Dependent Claim
16 words
The acetabular cup of claim 1, wherein said porous surface is a metallic beaded porous surface.
Claim 10
Dependent Claim
49 words
The acetabular cup of claim 1 wherein said spacers have substantially the same height and are positioned on the outer surface for providing a uniform space to be filled by bone cement between the acetabular cup and the supporting bone when the cup is positioned against said supporting bone.
Claim 11
Independent Claim
160 words
A method of preparing a metal-backed acetabular cup having acrylic spacers on the outer surface thereof comprising the following steps: (a) providing a porous surface over at least a portion of the metal outer surface of the cup; (b) placing the cup in a suitable holding fixture; (c) forming an acrylic material into a suitable shape for spacers; (d) holding a spacer against the porous surface in the desired predetermined position; (e) placing the horn of an ultrasonic machine in contact with the broad base area of the spacer; (f) introducing the ultrasonic energy; (g) melting the contact surface of the spacer, such that the acrylic contact surface melts and flows into the porous surface that the spacer is in contact with; (h) solidifying of said acrylic upon cessation of ultrasound energy, providing secure adherence of the spacer to the porous outer surface of the cup; and (i) repeating of steps (d) through (h) for each spacer to be adhered.
Claim 12
Independent Claim
160 words
A method of preparing a metal-backed acetabular cup having acrylic spacers on the outer surface thereof comprising the following steps: (a) providing a porous surface over at least a portion of the metal outer surface of the cup; (b) placing the cup in a suitable holding fixture; (c) forming an acrylic material into a suitable shape for spacers; (d) holding a spacer against the porous surface in the desired predetermined position; (e) placing the horn of an ultrasonic machine in contact with the broad base area of the spacer; (f) introducing the ultrasonic energy; (g) melting the contact surface of the spacer, such that the acrylic contact surface melts and flows into the porous surface that the spacer is in contact with; (h) solidifying of said acrylic upon cessation of ultrasound energy, providing secure adherence of the spacer to the porous outer surface of the cup; and (i) repeating of steps (d) through (h) for each spacer to be adhered.
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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) | 1989-01-27 | 1989-07-29 | 1990-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-01-27 | 1993-07-29 | 1994-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-01-27 | 1997-07-29 | 1998-01-28 | $7700.00 | Window Closed / Lapsed |