US6818172B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Oriented, cross-linked UHMWPE molding for orthopaedic applications
Assignee: DePuy Products Inc
•
Filing: 2001-09-24
•
Granted: 2004-11-16
•
Expires: 2021-09-24
Abstract
Abstract A process for forming an oriented orthopaedic implant prosthesis bearing, net-shape bearing, or near net-shape bearing includes the step of placing an irradiated UHMWPE preform or puck of a volume sufficient to accommodate the bearing in a compression mold and compression molding the irradiated preform. The molding is accomplished by applying heat and pressure to form the preform into a desired shape. The compression molding induces biaxial orientation in the formed bearing.
Inventors
- 👤 Richard King
- 👤 Donald E. McNulty
- 👤 Todd S. Smith
- 👤 Robert Richard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:26
CPC Classifications
B; B29; B29C; B29C43/00; B29C43/003; A; A61; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2/32; A61F2/34; A61F2/38; A61F2/389; A61F2/40; A61F2/4081; A61L; A61L27/00; A61L27/14; A61L27/16; B29C35/00; B29C35/02; B29C35/08; A61F2/3094; A61F2002/30001; A61F2002/30108; A61F2002/3011; A61F2002/30112; A61F2002/30133; A61F2002/30316; A61F2002/30329; A61F2002/30331; A61F2002/30362; A61F2002/30364; A61F2002/30367; A61F2002/30383; A61F2002/30403; A61F2/30767; A61F2/30771; A61F2002/3082; A61F2002/30822; A61F2002/30827; A61F2002/30878; A61F2002/30891; A61F2002/30892; A61F2/30942; A61F2002/30957; A61F2002/3412; A61F2/46; A61F2002/4631; A61F2220/00; A61F2220/0025; A61F2220/0033; A61F2230/00; A61F2230/0002; A61F2230/0004; A61F2230/0015; A61F2310/00; A61F2310/00005; A61F2310/00011; B29C35/0805; B29C2035/085; B29K; B29K2023/00; B29K2023/04; B29K2023/06; B29K2023/0658; B29K2023/0683; B29K2105/00; B29K2105/25; B29K2105/253; B29K2995/00; B29K2995/0037; B29K2995/005; B29K2995/0087; B29L; B29L2031/00; B29L2031/753; B29L2031/7532
Claims Analysis
Total Claims: 66
Claim 1
Independent Claim
92 words
A process for preparing an orthopaedic bearing, comprising the steps of: irradiating an ultrahigh molecular weight polyethylene preform with a dose of gamma radiation within a range from about 5.1 Mrad to about 50 Mrad; placing the preform in a compression molding press; heating the preform to a temperature that is greater than or substantially equal to the melting temperature of the ultrahigh molecular weight polyethylene; and compression molding the preform under a pressure effective to orient the ultrahigh molecular weight polyethylene outwardly from the direction of compression to form the bearing.
Claim 2
Dependent Claim
92 words
A process for preparing an orthopaedic bearing, comprising the steps of: irradiating an ultrahigh molecular weight polyethylene preform with a dose of gamma radiation within a range from about 5.1 Mrad to about 50 Mrad; placing the preform in a compression molding press; heating the preform to a temperature that is greater than or substantially equal to the melting temperature of the ultrahigh molecular weight polyethylene; and compression molding the preform under a pressure effective to orient the ultrahigh molecular weight polyethylene outwardly from the direction of compression to form the bearing.
Claim 3
Dependent Claim
20 words
The process of claim 1 , further comprising the step of cooling the bearing while maintaining the bearing under pressure.
Claim 4
Dependent Claim
31 words
The process of claim 1 , wherein the irradiating step includes irradiating the preform with a dose of gamma radiation within the range from about 5.1 Mrad to about 15 Mrad.
Claim 5
Dependent Claim
20 words
The process of claim 1 , wherein the compression molding step is effective to induce planar flow in the preform.
Claim 6
Dependent Claim
35 words
The process of claim 1 , wherein the compression molding step is effective to induce biaxial orientation of the ultrahigh molecular weight polyethylene in a number of planes which are transverse to a compression direction.
Claim 7
Dependent Claim
36 words
The process of claim 1 , wherein the compression molding step is effective to induce biaxial molecular orientation of the ultrahigh molecular weight polyethylene in a number of planes which are transverse to a compression direction.
Claim 8
Dependent Claim
36 words
The process of claim 1 , wherein the compression molding step is effective to induce radially-disposed molecular orientation of the ultrahigh molecular weight polyethylene in a number of planes which are transverse to a compression direction.
Claim 9
Dependent Claim
25 words
The process of claim 1 , wherein the compression molding step is effective to quench a population of residual free radicals present in the preform.
Claim 10
Dependent Claim
26 words
The process of claim 1 , wherein the compression molding step is effective to reduce a population of residual free radicals by about 90% or greater.
Claim 11
Dependent Claim
26 words
The process of claim 1 , wherein the compression molding step is effective to reduce a population of residual free radicals by about 95% or greater.
Claim 12
Dependent Claim
31 words
The process of claim 1 , wherein the compression molding step includes compressing the preform to form the bearing to a flow ratio within a range of 1.05 to about 1.7.
Claim 13
Dependent Claim
31 words
The process of claim 1 , wherein the compression molding step includes compressing the preform to form the bearing to a flow ratio within a range of 1.1 to about 1.3.
Claim 14
Dependent Claim
31 words
The process of claim 1 , wherein the compression molding step includes compressing the preform to form the bearing to a flow ratio within a range of 1.1 to about 1.2.
Claim 15
Dependent Claim
19 words
The process of claim 2 , wherein the cooling step is performed while the bearing is in the mold.
Claim 16
Dependent Claim
65 words
A process for preparing an oriented polyethylene orthopaedic bearing, comprising the steps of: placing an irradiated polyethylene preform into a compression molding press; and compression molding the preform so as to form the bearing by compressive forces effective to (i) orient the polyethylene outwardly from the direction of compression, and (ii) form the bearing at a flow ratio within a range of 1.1 to 1.3.
Claim 17
Dependent Claim
65 words
A process for preparing an oriented polyethylene orthopaedic bearing, comprising the steps of: placing an irradiated polyethylene preform into a compression molding press; and compression molding the preform so as to form the bearing by compressive forces effective to (i) orient the polyethylene outwardly from the direction of compression, and (ii) form the bearing at a flow ratio within a range of 1.1 to 1.3.
Claim 18
Dependent Claim
37 words
The process of claim 15 , wherein: the irradiated polyethylene preform includes an irradiated ultrahigh molecular weight polyethylene preform, and the placing step includes placing the irradiated ultrahigh molecular weight polyethylene preform into the compression molding press.
Claim 19
Dependent Claim
14 words
The process of claim 15 , further comprising the step of heating the preform.
Claim 20
Dependent Claim
18 words
The process of claim 17 , wherein the heating step is performed prior to the compression molding step.
Claim 21
Dependent Claim
18 words
The process of claim 17 , wherein the heating step is performed contemporaneously with the compression molding step.
Claim 22
Dependent Claim
24 words
The process of claim 17 , wherein the heating step includes heating the preform to a temperature above the melting temperature of the polyethylene.
Claim 23
Dependent Claim
18 words
The process of claim 17 , wherein the compression molding step is performed in a substantially oxygen-free atmosphere.
Claim 24
Dependent Claim
50 words
A process for preparing an oriented polyethylene orthopaedic net-shape bearing, comprising the steps of: placing an irradiated polyethylene preform into a compression molding press; and compression molding the preform so as to form the net-shape bearing by compressive forces effective to orient the polyethylene outwardly from the direction of compression.
Claim 25
Dependent Claim
50 words
A process for preparing an oriented polyethylene orthopaedic net-shape bearing, comprising the steps of: placing an irradiated polyethylene preform into a compression molding press; and compression molding the preform so as to form the net-shape bearing by compressive forces effective to orient the polyethylene outwardly from the direction of compression.
Claim 26
Dependent Claim
37 words
The process of claim 22 , wherein: the irradiated polyethylene preform includes an irradiated ultrahigh molecular weight polyethylene preform, and the placing step includes placing the irradiated ultrahigh molecular weight polyethylene preform into the compression molding press.
Claim 27
Dependent Claim
14 words
The process of claim 22 , further comprising the step of heating the preform.
Claim 28
Dependent Claim
18 words
The process of claim 24 , wherein the heating step is performed prior to the compression molding step.
Claim 29
Dependent Claim
18 words
The process of claim 24 , wherein the heating step is performed contemporaneously with the compression molding step.
Claim 30
Dependent Claim
24 words
The process of claim 24 , wherein the heating step includes heating the preform to a temperature above the melting temperature of the polyethylene.
Claim 31
Dependent Claim
29 words
The process of claim 22 , wherein the compression molding step includes compressing the preform under a pressure within the range from about 1,000 psi to about 15,000 psi.
Claim 32
Dependent Claim
32 words
The process of claim 22 , wherein the compression molding step includes compressing the preform to form of the net-shape bearing at a flow ratio within the range of 1.1 to 1.3.
Claim 33
Dependent Claim
18 words
The process of claim 22 , wherein the compression molding step is performed in a substantially oxygen-free atmosphere.
Claim 34
Dependent Claim
68 words
A process for preparing an oriented polyethylene orthopaedic bearing, comprising the steps of: placing a polyethylene preform, which has been irradiated with a dose of gamma radiation within a range from about 5.1 Mrad to about 50 Mrad, into a compression molding press; and compression molding the preform so as to form the bearing by compressive forces effective to orient the polyethylene outwardly from the direction of compression.
Claim 35
Dependent Claim
68 words
A process for preparing an oriented polyethylene orthopaedic bearing, comprising the steps of: placing a polyethylene preform, which has been irradiated with a dose of gamma radiation within a range from about 5.1 Mrad to about 50 Mrad, into a compression molding press; and compression molding the preform so as to form the bearing by compressive forces effective to orient the polyethylene outwardly from the direction of compression.
Claim 36
Dependent Claim
34 words
The process of claim 31 , wherein: the polyethylene preform includes an ultrahigh molecular weight polyethylene preform, and the placing step includes placing the ultrahigh molecular weight polyethylene preform into the compression molding press.
Claim 37
Dependent Claim
14 words
The process of claim 31 , further comprising the step of heating the preform.
Claim 38
Dependent Claim
24 words
The process of claim 33 , wherein the heating step includes heating the preform to a temperature above the melting temperature of the polyethylene.
Claim 39
Dependent Claim
31 words
The process of claim 31 , wherein the compression molding step includes compressing the preform to form the bearing to a flow ratio within a range of 1.1 to about 1.3.
Claim 40
Dependent Claim
20 words
The process of claim 15 , further comprising the step of cooling the bearing while maintaining the bearing under pressure.
Claim 41
Dependent Claim
20 words
The process of claim 2 , further comprising the step of cooling the bearing while maintaining the bearing under pressure.
Claim 42
Dependent Claim
20 words
The process of claim 31 , further comprising the step of cooling the bearing while maintaining the bearing under pressure.
Claim 43
Dependent Claim
19 words
The process of claim 1 , further comprising the step of preheating the preform prior to the placing step.
Claim 44
Dependent Claim
19 words
The process of claim 15 , further comprising the step of preheating the preform prior to the placing step.
Claim 45
Dependent Claim
19 words
The process of claim 22 , further comprising the step of preheating the preform prior to the placing step.
Claim 46
Dependent Claim
19 words
The process of claim 31 , further comprising the step of preheating the preform prior to the placing step.
Claim 47
Dependent Claim
51 words
The process of claim 1 , further comprising the step of soaking the preform for a period of time at a soak pressure which is less than the pressure generated by the pressure effective to orient the ultrahigh molecular weight polyethylene, wherein the soaking step is performed after the heating step.
Claim 48
Dependent Claim
44 words
The process of claim 17 , further comprising the step of soaking the preform for a period of time at a soak pressure which is less than the pressure generated by the compressive forces, wherein the soaking step is performed after the heating step.
Claim 49
Dependent Claim
44 words
The process of claim 24 , further comprising the step of soaking the preform for a period of time at a soak pressure which is less than the pressure generated by the compressive forces, wherein the soaking step is performed after the heating step.
Claim 50
Dependent Claim
44 words
The process of claim 33 , further comprising the step of soaking the preform for a period of time at a soak pressure which is less than the pressure generated by the compressive forces, wherein the soaking step is performed after the heating step.
Claim 51
Dependent Claim
44 words
The process of claim 1 , further comprising the step of exerting an initial pressure on the preform prior to the heating step, wherein the initial pressure is less than the pressure generated by the pressure effective to orient the ultrahigh molecular weight polyethylene.
Claim 52
Dependent Claim
44 words
The process of claim 1 , further comprising the step of exerting an intermediate pressure on the preform subsequent to the heating step, wherein the intermediate pressure is less than the pressure generated by the pressure effective to orient the ultrahigh molecular weight polyethylene.
Claim 53
Dependent Claim
37 words
The process of claim 17 , further comprising the step of exerting an initial pressure on the preform prior to the heating step, wherein the initial pressure is less than the pressure generated by the compressive forces.
Claim 54
Dependent Claim
37 words
The process of claim 17 , further comprising the step of exerting an intermediate pressure on the preform subsequent to the heating step, wherein the intermediate pressure is less than the pressure generated by the compressive forces.
Claim 55
Dependent Claim
37 words
The process of claim 24 , further comprising the step of exerting an initial pressure on the preform prior to the heating step, wherein the initial pressure is less than the pressure generated by the compressive forces.
Claim 56
Dependent Claim
37 words
The process of claim 24 , further comprising the step of exerting an intermediate pressure on the preform subsequent to the heating step, wherein the intermediate pressure is less than the pressure generated by the compressive forces.
Claim 57
Dependent Claim
37 words
The process of claim 33 , further comprising the step of exerting an initial pressure on the preform prior to the heating step, wherein the initial pressure is less than the pressure generated by the compressive forces.
Claim 58
Dependent Claim
37 words
The process of claim 33 , further comprising the step of exerting an intermediate pressure on the preform subsequent to the heating step, wherein the intermediate pressure is less than the pressure generated by the compressive forces.
Claim 59
Dependent Claim
44 words
The process of claim 1 , further comprising the step of soaking the bearing for a period of time, after the compression molding step, at a temperature which is greater than ambient temperature, wherein the bearing is maintained under pressure during the soaking step.
Claim 60
Dependent Claim
44 words
The process of claim 15 , further comprising the step of soaking the bearing for a period of time, after the compression molding step, at a temperature which is greater than ambient temperature, wherein the bearing is maintained under pressure during the soaking step.
Claim 61
Dependent Claim
44 words
The process of claim 22 , further comprising the step of soaking the bearing for a period of time, after the compression molding step, at a temperature which is greater than ambient temperature, wherein the bearing is maintained under pressure during the soak step.
Claim 62
Dependent Claim
44 words
The process of claim 31 , further comprising the step of soaking the bearing for a period of time, after the compression molding step, at a temperature which is greater than ambient temperature, wherein the bearing is maintained under pressure during the soaking step.
Claim 63
Dependent Claim
20 words
The process of claim 1 , further comprising the step of quenching the preform prior to the compression molding step.
Claim 64
Dependent Claim
20 words
The process of claim 15 , further comprising the step of quenching the preform prior to the compression molding step.
Claim 65
Dependent Claim
20 words
The process of claim 22 , further comprising the step of quenching the preform prior to the compression molding step.
Claim 66
Dependent Claim
20 words
The process of claim 31 , further comprising the step of quenching the preform prior to the compression molding step.
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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) | 2007-11-16 | 2008-05-17 | 2008-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2011-11-16 | 2012-05-17 | 2012-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2015-11-16 | 2016-05-17 | 2016-11-16 | $7700.00 | Window Closed / Lapsed |