US4554686A
Expired / Lapsed
US
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Polymethylmethacrylate bone cements and methods for preparing such bone cements
Assignee: TECHNICAL RESEARCH ASSOCIATES Inc A CORP OF UT
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Filing: 1984-02-29
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Granted: 1985-11-26
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Expires: 2004-02-29
Abstract
Abstract The present invention is directed to polymethylmethacrylate bone cement that is premixed and frozen so as to arrest the polymerization reaction at a suitable point. The frozen bone cement is treated by electromagnetic radiation to insure sterility. In use, the bone cement is warmed until it reaches a temperature and consistency suitable for use. The bone cement may be prepackaged in a syringe, or may be molded for use in connection with a particular prosthesis, or may be packaged unitarily with a prosthesis.
Inventors
- 👤 Charles D. Baker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 01:19
CPC Classifications
A; A61; A61L; A61L24/00; A61L24/04; A61L24/06; A61L2430/00; A61L2430/02
Claims Analysis
Total Claims: 49
Claim 1
Independent Claim
137 words
A method for preparing polymethylmethacrylate bone cement for use in attaching a surgical prosthesis to prepared bone tissue, the method comprising the steps of: mixing a bone cement composition including methylmethacrylate with a composition capable of initiating a polymerization of the methylmethacrylate; blending the bone cement composition until a desired degree of partial polymerization has occurred; placing substantially free flowing partially polymerized bone cement into syringe means; freezing the partially polymerized bone cement in order to substantially arrest polymerization of the methylmethacrylate in the bone cement composition; irradiating the frozen bone cement with suitable electromagnetic radiation capable of sterilizing the frozen bone cement without inducing substantial amounts of polymerization of the methylmethacrylate in the frozen bone cement; and storing the sterilized, frozen bone cement at a temperature below about -70° C. until use of the bone cement.
Claim 2
Independent Claim
137 words
A method for preparing polymethylmethacrylate bone cement for use in attaching a surgical prosthesis to prepared bone tissue, the method comprising the steps of: mixing a bone cement composition including methylmethacrylate with a composition capable of initiating a polymerization of the methylmethacrylate; blending the bone cement composition until a desired degree of partial polymerization has occurred; placing substantially free flowing partially polymerized bone cement into syringe means; freezing the partially polymerized bone cement in order to substantially arrest polymerization of the methylmethacrylate in the bone cement composition; irradiating the frozen bone cement with suitable electromagnetic radiation capable of sterilizing the frozen bone cement without inducing substantial amounts of polymerization of the methylmethacrylate in the frozen bone cement; and storing the sterilized, frozen bone cement at a temperature below about -70° C. until use of the bone cement.
Claim 3
Dependent Claim
37 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 1, wherein the freezing step is accomplished by placing the partially polymerized bone cement into freezing means capable of effecting rapid freezing of the bone cement.
Claim 4
Dependent Claim
28 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 2, wherein said rapid freezing of the bone cement is effected in less than about 15 seconds.
Claim 5
Dependent Claim
28 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 1, wherein the freezing step is accomplished by submerging the partially polymerized bone cement in liquid nitrogen.
Claim 6
Independent Claim
143 words
A method for preparing polymethylmethacrylate bone cement for use in attaching a surgical prosthesis to prepared bone tissue, the method comprising the steps of: mixing a bone cement composition including methylmethacrylate with a composition capable of initiating a polymerization of the methylmethacrylate; blending the bone cement composition until a desired degree of partial polymerization has occurred; forming the partially polymerized bone cement into a suitable shape for use with a particular surgical prosthesis; freezing the partially polymerized bone cement in order to substantially arrest polymerization of the methylmethacrylate in the bone cement composition; irradiating the frozen bone cement with suitable electromagnetic radiation capable of sterilizing the frozen bone cement without inducing substantial amounts of polymerization of the methylmethacrylate in the frozen bone cement; and storing the sterilized, frozen bone cement at a temperature below about -70° C. until use of the bone cement.
Claim 7
Independent Claim
143 words
A method for preparing polymethylmethacrylate bone cement for use in attaching a surgical prosthesis to prepared bone tissue, the method comprising the steps of: mixing a bone cement composition including methylmethacrylate with a composition capable of initiating a polymerization of the methylmethacrylate; blending the bone cement composition until a desired degree of partial polymerization has occurred; forming the partially polymerized bone cement into a suitable shape for use with a particular surgical prosthesis; freezing the partially polymerized bone cement in order to substantially arrest polymerization of the methylmethacrylate in the bone cement composition; irradiating the frozen bone cement with suitable electromagnetic radiation capable of sterilizing the frozen bone cement without inducing substantial amounts of polymerization of the methylmethacrylate in the frozen bone cement; and storing the sterilized, frozen bone cement at a temperature below about -70° C. until use of the bone cement.
Claim 8
Independent Claim
149 words
A method for preparing polymethylmethacrylate bone cement for use in attaching a surgical prosthesis to prepared bone tissue, the method comprising the steps of: mixing a bone cement composition including methylmethacrylate with a composition capable of initiating a polymerization of the methylmethacrylate; blending the bone cement composition until a desired degree of partial polymerization has occurred; forming the partially polymerized bone cement onto a surgical prosthesis; freezing the partially polymerized bone cement while formed on the surgical prosthesis in order to substantially arrest polymerization of the methylmethacrylate in the bone cement composition; irradiating the frozen bone cement and prosthesis with suitable electromagnetic radiation capable of sterilizing the frozen bone cement and the prosthesis without inducing substantial amounts of polymerization of the methylmethacrylate in the frozen bone cement; and storing the sterilized, frozen bone cement and prosthesis at a temperature below about -70° C. until use of the bone cement.
Claim 9
Independent Claim
149 words
A method for preparing polymethylmethacrylate bone cement for use in attaching a surgical prosthesis to prepared bone tissue, the method comprising the steps of: mixing a bone cement composition including methylmethacrylate with a composition capable of initiating a polymerization of the methylmethacrylate; blending the bone cement composition until a desired degree of partial polymerization has occurred; forming the partially polymerized bone cement onto a surgical prosthesis; freezing the partially polymerized bone cement while formed on the surgical prosthesis in order to substantially arrest polymerization of the methylmethacrylate in the bone cement composition; irradiating the frozen bone cement and prosthesis with suitable electromagnetic radiation capable of sterilizing the frozen bone cement and the prosthesis without inducing substantial amounts of polymerization of the methylmethacrylate in the frozen bone cement; and storing the sterilized, frozen bone cement and prosthesis at a temperature below about -70° C. until use of the bone cement.
Claim 10
Independent Claim
150 words
A method for preparing polymethylmethacrylate bone cement for use in attaching a surgical prosthesis to prepared bone tissue, the method comprising the steps of: mixing a bone cement composition including methylmethacrylate with a composition capable of initiating a polymerization of the methylmethacrylate; blending the bone cement composition until a desired degree of partial polymerization has occurred; freezing the partially polymerized bone cement in order to substantially arrest polymerization of the methylmethacrylate in the bone cement composition; irradiating the frozen bone cement with suitable electromagnetic radiation capable of sterilizing the frozen bone cement without inducing substantial amounts of polymerization of the methylmethacrylate in the frozen bone cement; and storing the sterilized, frozen bone cement at a temperature below about -70° C. until use of the bone cement; warming the frozen bone cement to a temperature suitable to permit it to be used to attach a surgical prosthesis to prepared bone tissue.
Claim 11
Independent Claim
150 words
A method for preparing polymethylmethacrylate bone cement for use in attaching a surgical prosthesis to prepared bone tissue, the method comprising the steps of: mixing a bone cement composition including methylmethacrylate with a composition capable of initiating a polymerization of the methylmethacrylate; blending the bone cement composition until a desired degree of partial polymerization has occurred; freezing the partially polymerized bone cement in order to substantially arrest polymerization of the methylmethacrylate in the bone cement composition; irradiating the frozen bone cement with suitable electromagnetic radiation capable of sterilizing the frozen bone cement without inducing substantial amounts of polymerization of the methylmethacrylate in the frozen bone cement; and storing the sterilized, frozen bone cement at a temperature below about -70° C. until use of the bone cement; warming the frozen bone cement to a temperature suitable to permit it to be used to attach a surgical prosthesis to prepared bone tissue.
Claim 12
Dependent Claim
19 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 1, wherein the electromagnetic radiation is gamma radiation.
Claim 13
Dependent Claim
21 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 8, wherein the gamma radiation is from a cobalt-60 source.
Claim 14
Dependent Claim
31 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 8, wherein the frozen bone cement is maintained at a temperature below about -50° C. during irradiation by gamma radiation.
Claim 15
Dependent Claim
20 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 1, wherein the electromagnetic radiation is an electron beam.
Claim 16
Dependent Claim
42 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 2, further comprising the step of placing the frozen bone cement into temperature maintenance means adapted to maintain the bone cement at a temperature wherein no substantial amount of polymerization occurs.
Claim 17
Dependent Claim
74 words
A sterile frozen bone cement composition including methylmethacrylate and suitable polymerization initiating agents wherein polymerization has been initiated but arrested at a desired degree of partial polymerization, said partially polymerized bone cement composition being placed into syringe means while in a substantially free-flowing condition and then frozen while in said syringe means, and wherein the frozen partially polymerized bone cement in the syringe is maintained at a temperature below about -70° C. until use.
Claim 18
Dependent Claim
74 words
A sterile frozen bone cement composition including methylmethacrylate and suitable polymerization initiating agents wherein polymerization has been initiated but arrested at a desired degree of partial polymerization, said partially polymerized bone cement composition being placed into syringe means while in a substantially free-flowing condition and then frozen while in said syringe means, and wherein the frozen partially polymerized bone cement in the syringe is maintained at a temperature below about -70° C. until use.
Claim 19
Dependent Claim
67 words
A sterile frozen bone cement composition including methylmethacrylate and suitable polymerization initiating agents wherein polymerization has been initiated but arrested at a desired degree of partial polymerization, said partially polymerized bone cement composition being formed into a suitable shape for use with a particular surgical prosthesis and then frozen, and wherein the partially polymerized bone cement is maintained at a temperature below about -70° C. until use.
Claim 20
Dependent Claim
67 words
A sterile frozen bone cement composition including methylmethacrylate and suitable polymerization initiating agents wherein polymerization has been initiated but arrested at a desired degree of partial polymerization, said partially polymerized bone cement composition being formed into a suitable shape for use with a particular surgical prosthesis and then frozen, and wherein the partially polymerized bone cement is maintained at a temperature below about -70° C. until use.
Claim 21
Dependent Claim
64 words
A sterile frozen bone cement composition including methylmethacrylate and suitable polymerization initiating agents wherein polymerization has been initiated but arrested at a desired degree of partial polymerization, said partially polymerized bone cement composition being formed on a surgical prosthesis and frozen while secured to said prosthesis, and wherein the partially polymerized bone cement is maintained at a temperature below about -70° C. until use.
Claim 22
Dependent Claim
64 words
A sterile frozen bone cement composition including methylmethacrylate and suitable polymerization initiating agents wherein polymerization has been initiated but arrested at a desired degree of partial polymerization, said partially polymerized bone cement composition being formed on a surgical prosthesis and frozen while secured to said prosthesis, and wherein the partially polymerized bone cement is maintained at a temperature below about -70° C. until use.
Claim 23
Dependent Claim
64 words
A bone prosthesis for use in the repair of damaged bone tissue comprising a suitable prothesis; and preformed sterile frozen bone cement secured thereto in a manner such that the prothesis and bone cement may be unitarily placed into prepared bone tissue to effect repair thereof, said frozen bone cement being partially polymerized, but having polymerization thereof arrested at a desired degree of polymerization.
Claim 24
Dependent Claim
64 words
A bone prosthesis for use in the repair of damaged bone tissue comprising a suitable prothesis; and preformed sterile frozen bone cement secured thereto in a manner such that the prothesis and bone cement may be unitarily placed into prepared bone tissue to effect repair thereof, said frozen bone cement being partially polymerized, but having polymerization thereof arrested at a desired degree of polymerization.
Claim 25
Dependent Claim
27 words
A bone prosthesis as defined in claim 16, wherein the prosthesis and associated bone cement are maintained at a temperature below about -70° C. prior to use.
Claim 26
Dependent Claim
37 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 5 wherein the freezing step is accomplished by placing the partially polymerized bone cement into freezing means capable of effecting rapid freezing of the bone cement.
Claim 27
Dependent Claim
28 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 18, wherein said rapid freezing of the bone cement is effected in less than about 15 seconds.
Claim 28
Dependent Claim
28 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 5, wherein the freezing step is accomplished by submerging the partially polymerized bone cement in liquid nitrogen.
Claim 29
Dependent Claim
19 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 5, wherein the electromagnetic radiation is gamma radiation.
Claim 30
Dependent Claim
21 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 21, wherein the gamma radiation is from a cobalt-60 source.
Claim 31
Dependent Claim
31 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 21, wherein the frozen bone cement is maintained at a temperature below about -50° C. during irradiation by gamma radiation.
Claim 32
Dependent Claim
20 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 5, wherein the electromagnetic radiation is an electron beam.
Claim 33
Dependent Claim
42 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 18, further comprising the step of placing the frozen bone cement into temperature maintenance means adapted to maintain the bone cement at a temperature wherein no substantial amount of polymerization occurs.
Claim 34
Dependent Claim
37 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 6 wherein the freezing step is accomplished by placing the partially polymerized bone cement into freezing means capable of effecting rapid freezing of the bone cement.
Claim 35
Dependent Claim
28 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 26, wherein said rapid freezing of the bone cement is effected in less than about 15 seconds.
Claim 36
Dependent Claim
28 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 6, wherein the freezing step is accomplished by submerging the partially polymerized bone cement in liquid nitrogen.
Claim 37
Dependent Claim
19 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 6, wherein the electromagnetic radiation is gamma radiation.
Claim 38
Dependent Claim
21 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 29, wherein the gamma radiation is from a cobalt-60 source.
Claim 39
Dependent Claim
31 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 29, wherein the frozen bone cement is maintained at a temperature below about -50° C. during irradiation by gamma radiation.
Claim 40
Dependent Claim
20 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 6, wherein the electromagnetic radiation is an electron beam.
Claim 41
Dependent Claim
42 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 26, further comprising the step of placing the frozen bone cement into temperature maintenance means adapted to maintain the bone cement at a temperature wherein no substantial amount of polymerization occurs.
Claim 42
Dependent Claim
37 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 7 wherein the freezing step is accomplished by placing the partially polymerized bone cement into freezing means capable of effecting rapid freezing of the bone cement.
Claim 43
Dependent Claim
28 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 34, wherein said rapid freezing of the bone cement is effected in less than about 15 seconds.
Claim 44
Dependent Claim
28 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 7, wherein the freezing step is accomplished by submerging the partially polymerized bone cement in liquid nitrogen.
Claim 45
Dependent Claim
19 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 7, wherein the electromagnetic radiation is gamma radiation.
Claim 46
Dependent Claim
21 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 37, wherein the gamma radiation is from a cobalt-60 source.
Claim 47
Dependent Claim
31 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 37, wherein the frozen bone cement is maintained at a temperature below about -50° C. during irradiation by gamma radiation.
Claim 48
Dependent Claim
20 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 7, wherein the electromagnetic radiation is an electron beam.
Claim 49
Dependent Claim
42 words
A method for preparing polymethylmethacrylate bone cement as defined in claim 34, further comprising the step of placing the frozen bone cement into temperature maintenance means adapted to maintain the bone cement at a temperature wherein no substantial amount of polymerization occurs.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-11-25 | 1989-05-27 | 1989-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-11-25 | 1993-05-27 | 1993-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-11-25 | 1997-05-27 | 1997-11-26 | $7700.00 | Window Closed / Lapsed |