Thomas Laubenthal v Howmedica Osteonics Corp

Case •

[2016] APO 18

•

7 April 2016

IP AUSTRALIA

AUSTRALIAN PATENT OFFICE

Thomas Laubenthal v Howmedica Osteonics Corp [2016] APO 18

Patent Application:                2010202320

Title:Orthopaedic PAEK-on-Polymer Bearings

Patent Applicant:                   Howmedica Osteonics Corp

Opponent:  Thomas Laubenthal

Delegate:  M. G. Kraefft

Decision Date:  7 April 2016

Hearing Date:  16 February 2016, in Melbourne

Catchwords:  PATENTS – section 59 – opposition to grant of a patent – grounds of lack of full description of invention, fair basis, manner of manufacture not made out - lack of novelty and lack of inventive step established on basis of prior art document – lack of clarity in two claims - opposition successful

Representation:  Patent applicant:  Mr Tom Cordiner, of counsel, assisted by Mr Adrian Crooks, patent attorney, Phillips Ormonde Fitzpatrick.

Opponent:Mr Ian Horak, of counsel, assisted by Mr Stephen O’Brien, patent attorney, Madderns.

IP AUSTRALIA

AUSTRALIAN PATENT OFFICE

Patent Application:                2010202320

Title:Orthopaedic PAEK-on-Polymer Bearings

Patent Applicant:                   Howmedica Osteonics Corp

Date of Decision:                   7 April 2016

DECISION

Claim 7 is not novel.  Additionally claims 1-3, 7, 8, 13 and 14 do not involve an inventive step.  Furthermore claims 6 and 12 are not clear.  The opposition is successful.

The applicant is allowed two (2) months from the date of this decision to propose suitable amendments to overcome the above defects.

I award costs in accordance with Schedule 8 against the applicant, Howmedica Osteonics Corp.

REASONS FOR DECISION

BACKGROUND

  1. Howmedica Osteonics Corp (“the applicant”) filed patent application 2010202320 on 3 June 2010.  The application claims an earliest priority date of 4 June 2009 from a US basic application 61/217,776.  Application 2010202320 was advertised accepted on 8 May 2014.

  2. Thomas Laubenthal (“the opponent”) filed a notice of opposition on 8 August 2014.  A statement of grounds and particulars followed on 7 November 2014.

  3. The parties completed the evidentiary stages on 13 July 2015.

    SPECIFICATION

  4. The present specification traces the background to the invention with the use of various materials in orthopaedic devices such as hip stems and acetabular cups.  Polyether ether ketone (“PEEK”) is an organic thermoplastic polymer in the polyaryl ether ketone (“PAEK”) family.  The specification states PAEK as having excellent resistance to acids and water and is capable of being sterilised by gamma radiation, ethylene oxide gas and steam.

  5. The specification cites two US patents stated to relate to hip stems made of PEEK including carbon-fibre reinforcements.  PEEK has also been proposed for use in acetabular cups as either backing or bearing materials.  The specification then cites two further US patent publications from 2007 that propose flexible acetabular cups made of PEEK.   In these proposals the opposite bearing, such as a femoral head, has been made of either a ceramic or metal bearing surface.  A US patent publication from 2009 is stated to relate to an all polymeric couple wherein each part is made of a composite material including carbon-fibre reinforcement. 

  6. Wear rates in bearing couples appear to have been an ongoing problem.  Furthermore, the specification notes that polyacetal-on-polyethylene was introduced as a complete polymer bearing couple in total knee arthroplasty in the 1980s and clinical results were published in the 1990s.  Because of poor gamma sterilisation resistance of the polyacetal material and inadequate fixation of the material’s femoral component to the bone, the use of polyacetal-on-polyethylene has been discontinued.

  7. The specification ends with 14 claims.  The independent claims are claims 1 and 7.  These claims read as follows.  The full set of claims appears at Annex A.

    1. An orthopedic prosthetic hip or knee joint comprising:

    a first prosthetic bearing component mounted on a femur having a first component bearing surface made completely of a non-carbon fiber reinforced poly ether ketone (sic) (PEEK) or a poly aryl ether ketone (PAEK) polymer that is non-carbon fiber reinforced; and
    a second prosthetic bearing component mounted on a proximal tibia or acetabulum having a second component bearing surface made of ultra-high molecular weight polyethylene (UHMWPE) cross-linked by irradiation, the first component and the second component bearing surfaces being in sliding engagement with one another, the PEEK or PAEK polymers having a shore D hardness higher than the UHMWPE cross-linked by irradiation.

    7.  An orthopedic prosthetic hip or knee joint comprising:

    a first hip or knee bearing surface formed of non-fiber reinforced PEEK; and
    a second hip or knee bearing surface in sliding contact with the first hip or knee bearing surface, the second bearing surface formed of ultra-high molecular weight polyethylene (UHMWPE).

    STATEMENT OF GROUNDS AND PARTICULARS

  8. The opponent listed seven grounds of opposition by reference to the relevant sections of the Patents Act.  The grounds of opposition included that the claimed invention was not a manner of manufacture, was not novel, did not involve an inventive step, was not useful, and inherently included within its scope a human being.  In respect to the complete specification, the opponent relied on the ground that the complete specification did not describe the invention fully, including the best method of performing the invention.  Finally the opponent included the ground that the claims were not clear or fairly based.  Several particulars relating to each of these grounds of opposition were also provided.  At the hearing the opponent did not pursue the grounds that the claimed invention was not useful and inherently included a human being. 

    EVIDENCE IN SUPPORT

  9. The opponent filed evidence in support in the form of two declarations from Dr Jenny Elizabeth Burke.  Dr Burke is presently a biomedical engineering consultant.  She has engineering qualifications from the University of Leeds in the United Kingdom (“UK”), specialising in tribology, biomedical engineering, the wear of orthopaedic implants, and biomechanics.  In industry, Dr Burke has almost 20 years of experience in the UK and Australia in the design, development, sales and marketing of orthopaedic implants globally.  Part of her responsibilities at various times also included liaison between orthopaedic surgeons and design engineers to develop and evaluate new innovations involving the use of new materials and operative techniques to further advance hip and knee replacement surgery.  Furthermore Dr Burke has provided education and training in respect to new orthopaedic implants to orthopaedic surgeons, registrars and sales teams.  Before the priority date of the present application, Dr Burke thus considered that she was skilled in the art of the design of orthopaedic implants and especially hip and knee replacement systems.

  10. In her first declaration, Dr Burke outlined improved hip and knee replacement systems over metal-on-metal, metal-on-polyethylene, ceramic-on-polyethylene and ceramic-on-ceramic systems.  The improved systems included hip replacement systems featuring cross-linked UHMWPE bearing surfaces.  One cross-linked UHMWPE bearing surface discussed in some detail in the declaration was a polyethylene designated X3TM.  In the mid to late 2000s, Dr Burke worked for an associated company of the one that developed the X3TM polyethylene.  She was principally responsible for the marketing and sales of that particular polyethylene, and technical training in respect thereto, in the South Pacific market.  X3TM polyethylene was used in the acetabulum as the softer bearing surface for articulating against a harder bearing surface on the femoral head, such as a metal or ceramic bearing surface.  Dr Burke principally regarded the above systems as commonly known or industry practice to those involved in product development in the orthopaedic implant industry.

  11. In her second declaration, Dr Burke commented on some prior art against the presently claimed invention and on several shortcomings within the present specification.

    EVIDENCE IN ANSWER

  12. The applicant filed evidence in answer from Dr Daniel Lawrynowicz.  At the time of his declaration, Dr Lawrynowicz was a senior director of advanced technology of a company in the same group of companies as the one Dr Burke worked for in respect to the development and marketing of the X3TM polyethylene.  Dr Lawrynowicz’s evidence principally distinguished the claimed invention from the prior art cited by the opponent and challenged Dr Burke’s stated shortcomings of the specification.

    EVIDENCE IN REPLY

  13. The opponent filed evidence in reply from Dr Burke.  In this evidence, Dr Burke exhibited several documents to outline the state of the art at the relevant time, particularly in respect to cross-linked UHMWPEs and including the X3TM polyethylene.  Dr Burke also responded to Dr Lawrynowicz’s comments on the opponent’s prior art to maintain the prior art disclosed the claimed invention and made the claimed invention obvious.

    APPLICABLE LAW

  14. As a consequence of the Intellectual Property Legislation Amendment (Raising the Bar) Act 2012 (“the Amendment Act”), there are substantial changes to the Patents Act 1990.  The date of effect of those changes was 15 April 2013.  The application of the Amendment Act in the present case depends on the date of the request for examination.  The applicant filed its request for examination on 20 November 2012.  Consequently the Patents Act as in force immediately before 15 April 2013 applies in the present case. 

  15. This means the former standard for opposition proceedings applies and the opponent bears the onus of establishing that it is clear or practically certain that a valid patent could not be granted (F Hoffman-La Roche AG v New England Biolabs Inc [2000] FCA 283 at [29], [67]; 50 IPR 305 at 311, 319; Commissioner of Patents v Sherman [2008] FCAFC 182 at [18], [22]; 79 IPR 426; Genetics Institute Inc v Kirin-Amgen Inc [1999] FCA 742; [1999] 92 FCR 106 at [17]).

  16. Section 18 of the Patents Act 1990 relates to patentable inventions.  Relevant parts of subsection (1) appear below.

    (1)Subject to subsection (2), an invention is a patentable invention for the purposes of a standard patent if the invention, so far as claimed in any claim:

    (a)   is a manner of manufacture within the meaning of section 6 of the Statute of Monopolies; and

    (b)   when compared with the prior art base as it existed before the priority date of that claim:

    (i)is novel; and

    (ii)involves an inventive step; and

    (c) is useful; and ………

    NOVELTY

  17. Under subsection 7(1), an invention is taken to be novel unless it is not novel in the light of the prior art base.  Information in a document forms part of the prior art base for the purposes of novelty if it was published before the priority date of a claim, or the information was contained in a specification published after the priority date of the claim under consideration and, if that information is, or were to be, the subject of a claim of the specification, that claim has, or would have, a priority date earlier than that of the claim under consideration (referred to as “whole of contents” novelty).

  18. It is well established that the general test for lack of novelty is the reverse infringement test. The classic formulation of this test is that given by Aickin J in Meyers Taylor Pty Ltd v Vicarr Industries Ltd, [1977] HCA 19 at [20]; 137 CLR 228 at 235:

    “The basic test for anticipation or want of novelty is the same as that for infringement and generally one can properly ask oneself whether the alleged anticipation would, if the patent were valid, constitute an infringement”.

  19. This test is satisfied if the alleged anticipation discloses all the essential features of the invention as claimed (see Nicaro Holdings Pty Ltd v Martin Engineering Co, [1990] FCA 40; (1990) 91 ALR 513 at 517). In order to meet this requirement, the prior art must "contain clear and unmistakeable directions to do what the patentee claims to have invented" (The General Tire & Rubber Company v The Firestone Tyre and Rubber Company Limited, [1972] RPC 457 at 486), (“General Tire”).  In a similar vein, what a prior art document teaches is to be distinguished from what might be “included” or “encompassed”.   “A prior broad disclosure thus may not be sufficient ‘in the absence of the skilled addressee understanding or perceiving’ the later claimed invention therein” (Sanofi-Aventis Australia Pty Ltd v Apotex Pty Ltd (No. 3), [2011] FCA 846 at [180]), (“Sanofi”).

  20. The opponent principally relied on the following patent documents.

    US 2007/0255412 by Hajaj et al (“Hajaj”)

  21. This document discloses a prosthetic device.  An illustration, from Figure 1, of the device as a knee implant is shown below. 

  22. While the figures mostly illustrate a prosthetic device for a knee joint, the disclosure contemplates the prosthetic device being any orthopaedic implant. For example, at [0035], the prosthetic device may also be a hip implant. At [0034] and [0035], where the prosthetic device embodies a total knee or hip implant, there is a first implant 12 and a second implant 14 bearing and articulating against the first implant 12. In respect to the first implant 12, it comprises a first component 50 that includes a surface 52 that is configured as an articular surface or bearing surface [0037]. It may be noted that the disclosure at this point also states this surface being designed to replace the natural surfaces of the tibia. Consistently then with [0035], where the prosthetic device is a total knee implant, the first implant 12 is a tibial component and the second implant 14 is a femoral component. By contrast, also at [0035], where the prosthetic device is a total hip implant, the first implant 12 is a femoral component and the second implant 14 is an acetabular component.

  23. While there may be a tendency to view the further disclosures of Hajaj as relating to the knee, as the figures mostly relate to a knee joint, it is noteworthy that in the immediately subsequent paragraphs there is no further reference to tibial, acetabular or femoral components for the knee or hip. Furthermore Dr Burke, at [26] of her second declaration in discussing [0038], referred to the first component 50 as the femoral component, that is, as the hip implant embodiment of Hajaj. Thus it would appear the further disclosures of Hajaj may apply to knee or hip implants. The first component 50 may be formed either partially or entirely of a polymer composite [0038]. An exemplary embodiment of the polymer composite is particles of polytetrafluoroethylene (“PTFE”), a first polymer, and PEEK, a second polymer. Alternatively the polymer composite is made of Nylon 6 (a commercially available semi-crystalline polyamide) and UHMWPE.

  24. Where the first component 50 is formed partially of the polymer composite, other materials suitable for use in orthopaedic implant applications may be included. For example, a biocompatible metal, such as a cobalt-chromium alloy, a titanium alloy, stainless steel, or tantalum, and/or a strong ceramic, and/or one or more high performance polymers, such as UHMWPE, and/or a polymer composite may be included. Preferably, at least the bearing surface 52 of the first component 50 is formed of the polymer composite [0040].

  25. Similarly the implant 14 may be made from the same range of other suitable materials for orthopaedic implant applications as described above for the first component 50 of implant 12 [0041].

  26. The applicant submitted that Hajaj did not disclose any specific combination of any of the above-mentioned materials.  Amongst the many possible combinations of materials, there was a component formed of a polymer composite that might include PEEK in combination with another polymer, and another component that might include UHMWPE in some form.  The applicant referred to the ICI Chemicals & Polymers Ltd v The Lubrizol Corporation Inc decision, [2000] FCA 1349 at [51], to characterise the opponent’s approach with the Hajaj disclosure as searching for the invention in the haystack of options. In the ICI decision, the Full Federal Court at [50] cautioned against having regard merely to the literal meaning of terms or the width of the class of refrigerants disclosed.  Rather the court emphasised important other aspects of the prior art disclosure, for example, that there were only two refrigerants exemplified and there was no disclosure of any tests or experiments involving any other refrigerants.

  27. It is correct that Hajaj discloses a variety of materials that may constitute each of implants 12 and 14.  One may also suggest the materials cannot be categorised to any particular class or classes since polymers, polymer composites, biocompatible metals and ceramics are all options.  On the other hand, Hajaj also specifically exemplifies, as emphasised by the ICI decision, the materials and their use on the bearing surfaces of an orthopaedic prosthetic hip or knee joint as claimed in claims 1 and 7 of the present application.  For instance, the first component 50 of implant 12 may be a PTFE/PEEK polymer composite [0038] and implant 14 may be made of UHMWPE [0041].

  28. Claims 1 and 7 of the application also define non-fiber reinforced PEEK.  There may be a question as to whether this defines unreinforced or pure PEEK, or alternatively reinforced PEEK that is reinforced by means other than fibre, or carbon fibre in the case of claim 1.  It would appear that little turns on this in the present case.  The specification and the evidence generally exemplified carbon-fibre reinforcement where PEEK was reinforced.  At the hearing, both parties concurred that Hajaj, absent any reference to carbon-fibre reinforced PEEK, disclosed non-fibre reinforced PEEK as claimed in the present case.  There being no further limitations in claim 7, I find that claim 7 is anticipated by Hajaj.

  29. Claim 1 has the further limitation of the juxtaposition of the first bearing component on a femur and the second bearing component on a proximal tibia or acetabulum.  As follows from above, the hip embodiment of Hajaj anticipates this aspect of claim 1.

  30. Claim 1 of the application further defines the first bearing surface being made completely of PEEK.  Hajaj refers to the first component 50 being formed of a polymer composite, for example PTFE/PEEK.  The opponent pointed out the passage at [0038] that particle ratios in the polymer composite can be fixed (constant) or variable (non-constant or graded) in the range of 0-100% and vice versa across the length, width and depth of the polymer composite.  The opponent submitted that Hajaj thus taught an implant which may at least have a bearing surface made completely of PEEK (that is, 100% PEEK) and still be considered a polymer composite.  On the other hand, the applicant submitted that other passages of Hajaj taught away from a component made of 100% PEEK.  At [0039], in an exemplary embodiment, a first polymer is selected to promote articulation, for example to achieve the objectives of reduced friction and reduced wear, and the second polymer may be PEEK, amongst other things.  On the other hand, while the first polymer may be for one or more laudable objectives, the passage at [0039] is clearly merely to an embodiment.  The teaching at [0038] is also reasonably clear.  Dr Burke, at [26] of her second declaration, construed the reference to the variation in particle ratios as explicitly teaching that the surface of the femoral component may be 100% PEEK or alternatively 100% PTFE.  Her conclusion was that Hajaj disclosed that a bearing surface of the femoral component may be formed of 100% PEEK.  I agree and find that Hajaj anticipates the feature of claim 1 of the application of the first bearing surface being made completely of PEEK.

  31. In respect to the feature in claim 1 of the application of the second bearing surface being made of UHMWPE cross-linked by irradiation, the opponent submitted through Dr Burke’s second declaration at [49] that the reference in Hajaj to UHMWPE would have been understood by the person skilled in the art as a reference to cross-linked or non-cross-linked UHMWPE.  The opponent thus stated that cross-linked UHMWPE was disclosed in Hajaj when that document was properly considered in the light of the common general knowledge.  On the other hand, for establishing lack of novelty as mentioned above, a prior broad disclosure may not be sufficient in the absence of the skilled addressee understanding or perceiving the later claimed invention therein (Sanofi-Aventis).  The nature of the UHMWPE, cross-linked or not cross-linked, is not specified in Hajaj.  Dr Burke’s statements merely indicate both variants would have suggested themselves to the person skilled in the art when reading Hajaj.  There is insufficient evidence before me that the skilled addressee in this case would have understood or perceived the UHMWPE in Hajaj to be cross-linked, let alone by irradiation as claimed in claim 1.  Put another way, there are no clear and unmistakable directions (General Tire) in Hajaj to UHMWPE cross-linked by irradiation.  This would render claim 1, and similarly the dependent claims 2-6 and 14, as novel over Hajaj.

  1. Claim 1 of the application also defines the PEEK or PAEK polymers having a shore D hardness higher than the UHMWPE cross-linked by irradiation.  Dr Burke acknowledged this feature was not explicitly disclosed in Hajaj but that it was implied due to the known material properties of PEEK being harder than cross-linked UHMWPE (at [52] of Dr Burke’s second declaration).  I agree and find that the relative shore D hardness feature of claim 1 is inherently disclosed by Hajaj.

  2. In respect to the claims dependent on claim 7, the feature of UHMWPE cross-linked by irradiation, amongst other things, is the subject of claims 8 and 13.  Consistent with the above discussion for claim 1 on this feature, I find that claims 8 and 13 are novel over Hajaj. 

  3. Claims 9-11 define the PEEK bearing comprising a layer of pure PEEK coated, molded or grafted onto a solid or porous substrate where the substrate is respectively a polymer composite, metallic, or ceramic or ceramic composite substrate. The opponent contended the relevant disclosure in Hajaj was at [0046]. This passage discusses an embodiment involving a porous substrate 67 which is part of a region of porosity 66, which in turn is part of a fixation portion 62 [0044]. The substrate 67 may be coated with suitable material, including a polymer composite [0047]. By cross-reference at [0047] to some US patent publications, the polymer composite may include PEEK. The fixation portion 62 is part of a second component 60 of the prosthetic device that secures the first component 50 in a patient’s body [0042]. Clearly then in Hajaj, it is not the first component 50, or the PEEK bearing as claimed, that comprises a layer of pure PEEK coated onto a substrate. Rather it is the fixation portion 62. I conclude that claims 9-11 are novel over Hajaj.

  4. Claim 12 defines a bone contacting surface having a porous PEEK layer for bone in-growth. The opponent relied on [0043] of Hajaj and Dr Burke’s evidence in reply at [53]. Dr Burke correctly noted that [0043] discloses a porous coating 63, on fixation portion 62, suitable for promoting bone in-growth. The coating 63 provides an interface between fixation portion 62 and the bone 30 and tissue 35 of the patient for bone and/or tissue fixation. Dr Burke further stated that the porous coating may be formed of a polymer composite and relied on the cross-reference to a US patent publication at [0043] to indicate that this included a PEEK layer. On the other hand, Dr Burke appeared to have misread [0043]. It is the fixation portion 62 that may be formed of the polymer composite. The coating may be any coating suitable for promoting bone in-growth. At [0043] the porous coating may be a sintered bead coating, a mesh coating, a plasma spray, or alternatively the coating may be a bioactive coating such as hydroxyapatite. There is no mention of the porous coating 63 being a material formed of PEEK. I conclude that claim 12 is novel over Hajaj.

  5. In summary, I conclude that only claim 7 is not novel over Hajaj.

    WO 2007/099307 by Invibio Limited (“Invibio”)

  6. This document relates to polymeric materials and particularly to the use of such materials in assemblies comprising first and second parts that bear against each other.  Preferred embodiments relate to the use of composite materials for bearing surfaces, for example for reconstructive joints of human bodies.  Partial or total hip or knee replacements are some of several applications mentioned in the Invibio document.

  7. Each of the first and second parts comprises a composite material including a polymeric material and carbon fibre.  The foot of page 6 mentions an especially preferred embodiment where the first polymeric material (of the first part) is PEEK.  Page 9 similarly mentions an especially preferred embodiment where the second polymeric material (of the second part) also is PEEK.

  8. The Invibio document is notable for the absence of disclosure of any component bearing surfaces that include UHMWPE in use in orthopaedic implants.  Test environments are discussed and test data provided in Invibio where various materials were assessed for their wear factors against each other.  The testing machine was a pin-on-plate machine.  Dr Burke in evidence in reply at [65] described pin-on-plate testing as a routine methodology for evaluating wear rates of materials for use in total hip joint replacement systems.  She indicated that, in such tests, the plate always represented the bearing surface of the femoral bearing component and the pin always represented the bearing surface of the acetabular bearing component. 

  9. Two test examples in Invibio specifically relate to UHMWPE as a test material against a material known as PEEK-OPTIMA LT1.  Invibio describes this material as a long term implantable grade PEEK obtainable from Invibio.  In her second declaration at [36], Dr Burke stated that she was familiar with PEEK-OPTIMA LT1 and understood that it was a non-carbon fibre reinforced PEEK.  I am prepared to accept that non-carbon fibre reinforced PEEK is disclosed in Invibio.

    In line with the plate representing the femoral bearing and the pin representing the acetabular bearing, Dr Burke concluded, at [66] in her evidence in reply, that the Invibio document disclosed a UHMWPE pin representing the bearing surface of the acetabular component and a PEEK plate representing the bearing surface of the femoral component of the hip joint replacement system. 

  10. In referring back to the claimed invention in the present specification, it appears somewhat difficult to transfer the Invibio disclosure of the non-carbon fibre reinforced PEEK and UHMWPE bearing surfaces in a pin-on-plate testing machine to the environment of an orthopaedic prosthetic hip or knee joint as claimed in claims 1 and 7 of the present application.  It may be that the plate was known in the art to represent the femoral bearing surface and the pin to represent the acetabular bearing surface.  It may also be that the transfer across the testing and applications environments could be within the disclosure of Invibio by reference to passages on page 16 of Invibio at lines 13-19.  Invibio states:-

    “Any feature of any aspect of the invention or embodiment described herein may be combined with any other feature of any aspect of an invention or embodiment described herein mutatis mutandis”. (Emphasis is in the original).

  11. The opponent referred to the subsequent paragraph where Invibio states that specific embodiments of the invention will now be described by way of example, and then describes the test examples mentioned above, amongst others. 

  12. On the other hand, the overall context of Invibio appears to be one of not (my emphasis) using UHMWPE in hip or knee replacement systems.  In its broadest form, the aspect of the invention in Invibio relates to the use of two bearing parts each comprising a composite material including, respectively, a first and second polymeric material, and carbon fibre.  See the paragraph bridging pages 2 and 3.  Preferably the first and second polymeric materials are the same (page 11 lines 14 and 15).  PEEK is especially preferred in each case.  See the foot of page 6 and the second paragraph on page 9.  Moreover, on page 3 at lines 20–25 of Invibio under the aspect of the invention, the selection of materials advantageously is such that the amount of wear debris produced and the rate of wear is significantly less than for corresponding parts made from other polymeric materials such as acetal or UHMWPE.  Similarly on page 24, further advantages of the described composite materials are mentioned, and include improved mechanical properties compared with UHMWPE thereby allowing thinner parts, and a greater degree of motion and design flexibility.   The context of Invibio is that UHMWPE is an inferior product compared with other polymeric materials that form the basis of the invention in Invibio.  I find there are no clear and unmistakable directions in Invibio, when read in context, of an orthopaedic prosthetic hip or knee joint as claimed in the present application having a component bearing surface made of UHMWPE.

  13. I conclude the present claims are novel over Invibio.

    INVENTIVE STEP

  14. Subsection 7(2) of the Patents Act 1990 states that an invention is taken to involve an inventive step unless it would have been obvious to a person skilled in the art in the light of the common general knowledge, considered alone or together with the prior art. A document is prior art for this purpose if "a skilled person mentioned in subsection (2) could, before the priority date of the relevant claim, be reasonably expected to have ascertained, understood, regarded [the document] as relevant" (Subsection 7(3) at the relevant time).

  15. The test for whether an invention is obvious is whether it would have been a matter of routine to proceed to the claimed invention. In Wellcome Foundation Ltd v VR Laboratories (Aust.) Pty Ltd, [1981] HCA 12 at [45], 148 CLR 262 at 286, (“Wellcome”), Aickin J stated:

    "The test is whether the hypothetical addressee faced with the same problem would have taken as a matter of routine whatever steps might have led from the prior art to the invention, whether they be the steps of the inventor or not."

  16. The High Court in Aktiebolaget Hässle v Alphapharm Pty Ltd, [2002] HCA 59, (2002) 56 IPR 129 at [50] – [53], (“Alphapharm”), appeared to approve of the Wellcome test.  In discussing what was meant by a matter of routine the High Court noted and accepted an affinity with the approach in Olin Mathieson Chemical Corporation v Biorex Laboratories Ltd, (1970) 87 RPC 157, of whether the person skilled in the art would directly be led as a matter of course to try what was claimed in the expectation that it might well produce a useful alternative. In Lockwood Security Products Pty Ltd v Doric Products Pty Ltd [No. 2], [2007] HCA 21, (2007) 235 ALR 202, general principles regarded to be of continuing relevance, at [50] – [52], were that “obvious” means “very plain”, a scintilla of invention remains sufficient to support the validity of a patent, there must be some difficulty overcome, some barrier to be crossed, and an invention must be beyond the skill of the calling.

  17. Where the invention lies in a combination of integers, the question is not whether each individual integer was obvious but rather whether the combination as a whole was obvious when compared to the prior art base.  In Alphapharm at [41], the High Court stated:

    “The claim is for a combination, the interaction between the integers of which is the essential requirement for the presence of an inventive step.  It is the selection of the integers out of ‘perhaps many possibilities’ which must be shown by Alphapharm to be obvious, bearing in mind that the selection of the integers in which the invention lies can be expected to be a process necessarily involving rejection of other possible integers.”

    Person Skilled in the Art

  18. In Root Quality Pty Ltd v Root Control Technologies Pty Ltd, [2000] FCA 980, Finkelstein J stated at [70] and [71] that the skilled addressee is the person to whom the patent is addressed and who must construe it. Such person works in the art or science with which the invention is connected or is likely to have a practical interest in the subject matter of the invention. A variety of people may have that interest. Finkelstein J further noted various descriptions given to the skilled addressee. These included the “uninventive skilled worker in the particular field” (Leonardis v Sartas No 1 Pty Ltd, (1996) 67 FCR 126) and the “person skilled in the art” (Genentech Inc v Wellcome Foundation Ltd, (1989) 15 IPR 423).

  19. The opponent submitted that Dr Burke was an appropriate person skilled in the art, being one highly skilled in the art of the design of orthopaedic implants and especially hip and knee replacement systems at the relevant time.  The applicant submitted that Dr Burke’s knowledge was not representative of the common general knowledge in the art, particularly in respect to the X3TM polyethylene.  Given Dr Burke’s responsibilities with marketing, sales and technical training in respect to the X3TM polyethylene, the applicant stated that Dr Burke was in an exceptional position regarding her knowledge and awareness of that product.  Furthermore her level of knowledge of the X3TM polyethylene would have been greater than that of the general industry (Dr Lawrynowicz’s evidence at [13]).

  20. In the present case the opponent would appear to be correct in its outline of the art to which the alleged invention pertains.  That is, the art relates to the design of orthopaedic implants and especially hip and knee replacement systems.  Dr Burke and Dr Lawrynowicz both would appear to be eminently qualified and experienced in this field.  The former has significant knowledge and experience of the developments of hip and knee replacement systems up to and including the use of X3TM, while the latter has significant experience of materials for orthopaedic prosthetics and is a named inventor on numerous patents in that field including the present patent application.  One could suggest that both declarants may thus be over-qualified to be representative of the ordinary, non-inventive person skilled in the art in the present case.  On the other hand, as will be apparent later, little if anything turns on this in the present case.

    Common General Knowledge

  21. The opponent submitted through Dr Burke’s evidence that the following was common general knowledge in the field at the relevant time.  Various types of hip and knee replacement systems were well known with different combinations of metal, ceramic and polymer systems in use.  When selecting different materials, the material selected for the acetabular component was almost always selected as the softer component so that the acetabular component wore in preference to the femoral head component.  It was understood that there were deficiencies in metal-on-metal hip replacement systems such as metal ion release arising from wear and the potential for development of local inflammatory reactions.  Systems marketed in Australia which sought to overcome the difficulties with metal components included those with UHMWPE bearing surfaces.  One widely promoted UHMWPE bearing surface was the X3TM polyethylene.

  22. The applicant did not dispute that PEEK and UHMWPE were known materials which had been used, separately, in prosthetic applications. In evidence in reply with some examples, Dr Burke at [27]-[31] described the availability and use of PEEK in orthopaedic prosthetic joints as common before the priority date, together with the knowledge of its material properties. She also noted that several suppliers of medical grade PEEK were listed in the specification at [0054]. Moreover the specification also describes PEEK as the most commercialised PAEK [0002]. I am prepared to accept that PEEK in use in orthopaedic implants was common general knowledge at the relevant time.

  23. The history of UHMWPE may be traced from the opponent’s evidence.  The first industrial highly cross-linked UHMWPE was prepared in the 1930s by irradiating an extruded tube of high-density polyethylene with an electron beam.  The evolution of UHMWPE as a prosthetic bearing material dated from the 1960s.  Highly cross-linked UHMWPE bearings were introduced in the late 1990s (exhibits JB-2 and JB-9).  The applicant noted concerns with highly cross-linked UHMWPE, particularly in respect to fatigue resistance (exhibits JB-12 and JB-13).  For this and some other reasons, highly cross-linked UHMWPE had not become so well accepted by orthopaedic manufacturers and surgeons in total knee arthroplasty.  There were perceived risks associated with abrasion, fatigue and fracture resistance (exhibit JB-10).  However the use of highly cross-linked UHMWPE had become widespread as hip replacements (exhibits JB-2 and JB-9).  Cross-links may be formed chemically or by irradiation of UHMWPE.  The latter method was used for orthopaedic applications due to concerns regarding biocompatibility of polyethylenes with chemically created cross-links.  Irradiation created free radicals in the polyethylene molecules mainly due to breaking C-H bonds.  Free radicals in proximity react to form cross-links.  For each cross-link formed, two free radicals were eliminated.  Heating the polyethylene provided molecular mobility allowing free radicals not in proximity to cross-link.  Most highly cross-linked UHMWPEs from the late 1990s used re-melting to virtually eliminate free radicals.  This process though came at the expense of reduced strength because the material recrystallised (exhibit JB-9).  Dr Burke’s description at [17] in evidence in reply of a text book example indicated that, by 2004, the proliferation of cross-linking technology into hip replacements, and more recently knee replacements, had resulted in at least six proprietary, radiation cross-linked and thermally treated UHMWPEs in the clinical market (exhibit JB-10).  The X3TM polyethylene dated from 2007, two years before the priority date of the present application.  This product was characterised by a process of production consisting of three cycles each involving irradiation followed by annealing.  For example, the radiation dose in each stage may have been 30 kGy leading to a cumulative dose across the three cycles of 90 kGy.  Each cycle of irradiation to a relatively low dose of 30 kGy followed by annealing allowed a higher cross-link density than using the same total dose of 90 kGy followed by annealing in a single cycle (exhibit JB-2).  This process enabled strength to be retained in the material while reducing free radical content to insignificant levels (exhibit JB-9).

  24. From the above, I would conclude that radiation, highly cross-linked UHMWPE and its material properties and use in hip replacements were common general knowledge in the field at the relevant time.  I have some reservation about the X3TM polyethylene.  As also mentioned above, the introduction of the X3TM polyethylene was just two years before the priority date.  Moreover Dr Burke was clearly in a superior position regarding knowledge of the X3TM polyethylene’s properties, its initial production and its entry into the market.  Consequently I treat her evidence in this respect with some caution.  It may be that promotion, presentations, distribution and training in respect to X3TM progressed relatively quickly in the clinical field as exemplified in Dr Burke’s evidence (for example exhibits JB-9 and JB-12).  The specification also discusses several examples involving X3TM.  On the other hand I am not satisfied from the evidence in this case that the X3TM polyethylene was widely regarded and used such as to have become common general knowledge by the priority date.  In any case, as alluded to earlier, little would appear to turn on this.  The claims of the application generally define the broader context of a bearing surface of UHMWPE cross-linked by irradiation (claim 1) or of just simply UHMWPE (claim 7).

    Whether There is an Inventive Step

  25. The opponent submitted that the claimed invention lacked an inventive step in the light of the common general knowledge alone, or together with either one of Hajaj or Invibio.  At the hearing, both parties concurred that the person skilled in the art could be reasonably expected to have ascertained, understood and regarded Hajaj and Invibio as relevant.

    Common General Knowledge Alone

  26. As mentioned earlier, the wear rates in bearing couples appear to have been an ongoing problem.  Additionally the evidence indicates the metal ion release arising from wear in metal-on-metal couples produced further problems such as potential local inflammatory reactions (Dr Burke’s first declaration at [38]).

  27. Claims 1 and 7 of the application both define at least the combination of a PEEK-on-UHMWPE bearing couple in an orthopaedic prosthetic hip or knee joint.  While it may be that the use of PEEK and highly cross-linked UHMWPE separately in orthopaedic prosthetic applications with other bearing surfaces such as metal or ceramic was common general knowledge, the combination of those two claimed materials as opposing bearing surfaces is an entirely different matter.  The opponent suggested there was no barrier overcome in selecting PEEK and UHMWPE to perform their known functions of providing superior wear characteristics, particularly where there was a desire to dispense with metallic bearings.  There appear to be at least two flaws with this approach.  Firstly the approach does not account for altered functions of one or both of the materials when combined.  As stated by the applicant, citing Alphapharm (supra) at [65], in assessing whether a claim for a combination involves an inventive step, the focus must be on the interaction between the integers in combination and not on each feature or integer separately.  In the present case, contrary to the use of PEEK as a softer component in the past against metal or ceramic, the claimed combination requires PEEK to be used as the harder component against the softer UHMWPE surface in orthopaedic devices.  Secondly, a desire to dispense with metallic bearings would presuppose that an alternative solution already existed.  There is simply insufficient evidence before me in this case to satisfy me that the PEEK-on-UHMWPE combination would have been common general knowledge at the relevant time. 

  1. I conclude the claims of the application have an inventive step in the light of the common general knowledge alone.

    Hajaj

  2. Earlier I found that claim 7 was not novel over Hajaj.  Consequently there would have been no steps required of the hypothetical addressee at the relevant time to lead from the Hajaj prior art to the claimed invention (Wellcome).  I conclude that claim 7 does not involve an inventive step over Hajaj.

  3. As discussed above, claim 1 of the application materially only differs from Hajaj by defining the UHMWPE to be cross-linked by irradiation.  Since I have determined that this feature was common general knowledge at the relevant time, and that in the environment of desired lower wearing materials it was an obvious technical expedient to employ, then I find that claim 1 does not involve an inventive step over Hajaj.  Claim 13, whilst appended to claim 7, is in essentially the same terms.  Consequently I find that claim 13 also does not involve an inventive step over Hajaj.

  4. Claim 2 adds the feature to claim 1 that the UHMWPE polymer may be a mono-polymer, co-polymer, or polymer with surface grafting or coating.  I expect the mono-polymer or co-polymer variants would have been well within the reach and understanding of the person skilled in the art at the relevant time.  I conclude that claim 2 does not involve an inventive step.

  5. Claim 3 adds the feature of the PEEK bearing being a stand-alone component.  The specification at [0008] appears to describe this feature in the context of a bearing solely of pure PEEK.  I have found earlier that Hajaj at [0038] adequately discloses a bearing surface being made completely of PEEK.  I find the feature of a PEEK bearing itself being a stand-alone component to lack an inventive step.

  6. Claims 4 and 5 are substantially the same as claims 9 and 11, respectively, although dependent on claim 1 in the former case as opposed to claim 7 in the latter case.  Earlier I noted that claims 9 and 11, together with claim 10, defined the PEEK bearing to comprise a layer of pure PEEK coated, molded or grafted onto various types of solid or porous substrates.  Hajaj discloses the fixation portion 62 as comprising such a layer of pure PEEK, not the first component 50 or PEEK bearing.  While it may appear simple that such a layer may be placed on other components of a prosthetic device from what is disclosed, I would find the evidence is insufficient as to the obviousness at the relevant time of the PEEK bearing having the layer of pure PEEK coated, molded or grafted onto a substrate, instead of the fixation portion.  I conclude that claims 4, 5, and 9-11 have an inventive step over Hajaj.

  7. Claims 6 and 12 define a bone contacting surface having a porous PEEK layer for bone in-growth.  Hajaj discloses a porous coating 63 interfacing between fixation portion 62 and bone and tissue of a patient.  There is no mention in Hajaj of this porous coating being formed of PEEK.  Rather it is the fixation portion 62 that may be formed of PEEK.  Again, the obviousness at the relevant time of a different component of the prosthetic device, compared with Hajaj, having a porous PEEK layer is not readily apparent from the evidence.  I conclude that claims 6 and 12 have an inventive step over Hajaj.

  8. Claim 8 adds the feature to claim 7 that the UHMWPE is cross-linked at least three times by irradiation, heating after irradiation and cooling after each heating.  The X3TM polyethylene would appear to fit this definition.  As mentioned at the outset, wear rates in bearing couples appear to have been an ongoing problem in orthopaedic devices such as hip stems and acetabular cups.  The X3TM polyethylene was known for its higher cross-link density at lower individual irradiation doses leading to lower wear rates.  The process of production also enabled strength to be retained in the X3TM material while reducing free radical content to insignificant levels (exhibit JB-9).  As such, X3TM was a superior product compared with previous highly cross-linked UHMWPEs.  Furthermore, Dr Burke’s evidence indicated there was significant promotion in the marketing and educational literature of X3TM and its material properties (for example exhibits JB-2 and JB-9).  I am satisfied the person skilled in the art could be reasonably expected to have ascertained such literature, understood it and regarded it as relevant.  In the above context I am also satisfied the person skilled in the art, faced with the ongoing problem of wear rates in orthopaedic devices, would have taken X3TM as a matter of routine, or would have directly been led as a matter of course to try X3TM, for an orthopaedic implant as claimed in claim 8.  I conclude that claim 8 does not involve an inventive step over Hajaj.

  9. Claim 14 adds the definition to claim 1 of an orthopaedic prosthetic joint substantially as described in the specification with reference to the accompanying figures.  I would conclude that claim 1 defines the orthopaedic prosthetic joint substantially as described in the specification.  Consequently the only substantive difference between claims 1 and 14 may be in the drawings.  On the other hand, the drawings illustrate wear factors amongst various combinations of PEEK, UHMWPE and other materials in test situations.  As such they provide no real limitation to the orthopaedic prosthetic joint as claimed.  Like claim 1, I conclude that claim 14 does not involve an inventive step over Hajaj.

  10. In summary, I conclude that claims 1-3, 7, 8, 13 and 14 do not involve an inventive step over Hajaj.

    Invibio

  11. Earlier I determined that Invibio contained no clear and unmistakable directions of an orthopaedic prosthetic hip or knee joint having a component bearing surface made of UHMWPE.  The opponent submitted that Invibio disclosed pin-plate testing for PEEK-UHMWPE in the context of use of those materials in hip and knee implants.

  12. On the other hand, as mentioned earlier, the overall context of Invibio appears to be one of not (my emphasis) using UHMWPE in hip or knee replacement systems.  The applicant pointed out through Dr Lawrynowicz’s evidence at [41] that the test example involving a UHMWPE pin and a PEEK-OPTIMA LT1 plate is shown in Invibio with the highest wear factors of any combination of the materials tested.  Moreover, as mentioned earlier, on page 3 of Invibio, the selection of materials advantageously is such that the amount of wear debris produced and the rate of wear is significantly less than for corresponding parts made from other polymeric materials such as acetal or UHMWPE.  Similarly on page 24, further advantages of the described composite materials are mentioned, and include improved mechanical properties compared with UHMWPE thereby allowing thinner parts, and a greater degree of motion and design flexibility.  Clearly Invibio teaches away from using UHMWPE.

  13. I conclude the present claims have an inventive step over Invibio.

    FULL DESCRIPTION OF THE INVENTION

  14. The opponent submitted that, due to the material characteristics of PEEK and UHMWPE and the complex load requirements of a hip or knee joint, the skilled person would need to be provided with detailed instructions on the process parameters required to manufacture the layers and substrate to produce a joint that satisfied the stated objectives of the invention.  In her second declaration at [64] and [65], Dr Burke criticised the specification’s lack of any description concerning the design considerations and engineering aspects of a hip or knee joint replacement system.  For example she stated there was no disclosure that provided any instructions or even guidance as to how the bearing components are mounted to the femur, or the proximal tibia or the acetabulum, nor specifications and considerations in respect to a PEEK layer on several substrate types.

  15. Dr Lawrynowicz, at [52] and [53] in evidence in answer, stated that he understood the specification to be principally directed to PAEK-on-polymer, and particularly PEEK-on-UHMWPE, bearing couples for use in orthopaedic prosthetic joints.  The specification did not appear to be directed to every technical aspect such as the manner in which such prosthetics were mounted to a patient.  Dr Lawrynowicz concluded that persons having expertise in the area of orthopaedic prosthetic joints would have no difficulty in applying the teachings of the specification.

  16. It is noteworthy that Dr Burke’s commentary is principally directed to the juxtaposition of bearing components per se with parts of the human body, and PEEK on various types of substrates.  The nature of the materials used would appear to be largely irrelevant from that discussion.  Moreover, I have found the evidence has established that PEEK and UHMWPE have separately been extensively used in orthopaedic implants as bearing surfaces against materials such as metal or ceramic.  It would appear there was widespread experience at the relevant time in applying orthopaedic implants to the human body that consisted of a range of materials including PEEK or UHMWPE.  I agree with Dr Lawrynowicz in finding that the person skilled in the art would have no difficulty from the specification in producing an orthopaedic prosthetic joint as claimed.

  17. I conclude the alleged invention is fully described in the specification.

    FAIR BASIS

  18. In Lockwood Security Products Pty Ltd v Doric Products Pty Ltd, [2004] HCA 58, 217 CLR 274, at [69], the requirement for fair basis was put as a need for a real and reasonably clear disclosure of what is claimed.

  19. The opponent submitted that claim 7 and its dependent claims lacked fair basis.  With reference to [0014] and [0019] of the specification, the opponent stated the alleged invention used PEEK as the harder bearing part articulating against a softer UHMWPE surface.  Claim 7 does not specify which bearing surface comprises which material.  It may be that there was a preference in the art for the material selected for the acetabular cup, for example, to be the softer material so that the acetabular component wore in preference to the femoral head component.  Similarly the examples in the descriptive part of the specification generally referred to PEEK heads against UHMWPE cups.  On the other hand the specification, in broad terms for example at [0007b]–[0019], does not appear to require such restriction of PEEK or UHMWPE to particular components.  I conclude that claim 7 and its dependent claims are fairly based on this point.

  20. The opponent also noted that claim 7 was not limited to cross-linked UHMWPE as disclosed in the specification.  Again, while there may have been a preference for cross-linked UHMWPE in the art and while the specification discusses X3TM in particular, I am unable to find any substantive requirement in the specification that the UHMWPE must be cross-linked.  In fact, paragraph [0019] specifically states in the last sentence that any UHMWPE, whether cross-linked or not, could be utilised.

  21. Finally, in respect to claims 6 and 12, the opponent objected to the absence of reference to a bone contacting surface in body of the specification.  On the other hand, the orthopaedic prosthetic joint as claimed must inherently have at least one bone contacting surface somewhere.

  22. I conclude that all the present claims are fairly based.

    CLARITY

  23. Claims 6 and 12 add the feature of a bone contacting surface having a porous PEEK layer for bone in-growth.  The opponent submitted there was no defined relationship between the bone contacting surface and the integers defined in claims 1 and 7, respectively.  The applicant submitted that the subject of claims 1 and 7, being to an orthopaedic prosthetic hip or knee joint, made it self-evident that the prosthetic joint bore components mounted to a bone and therefore the prosthetic joint would have a bone contacting surface. 

  24. It may be that the subject of claims 1 and 7 inherently requires a bone contacting surface to be associated with one or more defined components of the orthopaedic prosthetic joint.  On the other hand, the claims may envisage more.  The absence of a juxtaposition of the bone contacting surface with any previously defined features of the claims leaves claims 6 and 12 open to including in their scope the bone contacting surface being part of any unspecified and undefined component(s) of the orthopaedic prosthetic joint.  I conclude that claims 6 and 12 are unclear.

    MANNER OF MANUFACTURE

  25. The opponent submitted that the claims were a mere selection of known materials and there was no interworking relationship between the two materials recited in the claims (Commissioner of Patents v Microcell Ltd, [1959] HCA 71, (1959) 102 CLR 232). Both materials were stated to perform their known function in an orthopaedic implant.

  26. The NV Philips Gloeilampenfabrieken v Mirabella International Pty Ltd decision, [1995] HCA 15, 183 CLR 655, considered whether there was a general threshold requirement of newness or inventiveness in S18(1)(a) of the Patents Act 1990.  The decision stated that the threshold requirement of an alleged invention meant that, if it was apparent on the face of the specification that the quality of inventiveness necessary for there to be a proper subject of letters patent was absent, one need go no further. 

  27. At [0014] of the specification, PEEK was used previously as the softer component in place of UHMWPE against a metal or ceramic bearing.  On the other hand the alleged invention uses PEEK as the harder, non-sacrificial component against UHMWPE.  Additionally, the specification states at [0015] that the PEEK-on-UHMWPE bearing couple has a lower wear rate than the traditional metal-on-UHMWPE couple.  I am satisfied there is a proper interworking relationship between the claimed materials and that the requisite level of inventiveness is apparent on the face of the specification.

    CONCLUSION

  28. I have found that claim 7 is not novel.  Additionally I have found that claims 1-3, 7, 8, 13 and 14 do not involve an inventive step.  Furthermore claims 6 and 12 are not clear.  The opposition is successful.

  29. I allow the applicant two (2) months from the date of this decision to propose suitable amendments to overcome the above defects.

    COSTS

  30. Both parties sought their costs in this opposition.  In the present case I see insufficient reason to depart from the normal practice that costs follow the event.  The opposition is successful.  I award costs in accordance with Schedule 8 against the applicant, Howmedica Osteonics Corp.

    M. G. Kraefft
    Delegate of the Commissioner of Patents

    Annex A

    1.An orthopedic prosthetic hip or knee joint comprising:

    a first prosthetic bearing component mounted on a femur having a first component bearing surface made completely of a non-carbon fiber reinforced poly ether ketone (sic) (PEEK) or a poly aryl ether ketone (PAEK) polymer that is non-carbon fiber reinforced; and
    a second prosthetic bearing component mounted on a proximal tibia or acetabulum having a second component bearing surface made of ultra-high molecular weight polyethylene (UHMWPE) cross-linked by irradiation, the first component and the second component bearing surfaces being in sliding engagement with one another, the PEEK or PAEK polymers having a shore D hardness higher than the UHMWPE cross-linked by irradiation.

    2.The orthopedic prosthetic joint as set forth in claim 1 wherein the UHMWPE polymer may be mono-polymer, co-polymer, polymer with surface grafting or coating.

    3.The orthopedic prosthetic joint as set forth in claim 1 wherein the PEEK bearing is a stand-alone component.

    4.The orthopedic prosthetic joint as set forth in claim 1 wherein the PEEK bearing comprises a layer of pure PEEK coated, molded or grafted onto a solid or porous polymer substrate.

    5.The orthopedic prosthetic joint as set forth in claim 1 wherein the PEEK bearing comprises a layer of pure PEEK coated, molded or grafted onto a solid or porous ceramic substrate.

    6.The orthopedic prosthetic joint as set forth in claim 1 wherein a bone contacting surface comprises a porous PEEK layer for bone ingrowth.

    7.An orthopedic prosthetic hip or knee joint comprising:

    a first hip or knee bearing surface formed of non-fiber reinforced PEEK; and
    a second hip or knee bearing surface in sliding contact with the first hip or knee bearing surface, the second bearing surface formed of ultra-high molecular weight polyethylene (UHMWPE).

    8.The orthopedic implant as set forth in claim 7, wherein the UHMWPE is cross-linked at least three times by irradiation, heating after irradiation and cooling after each heating.

    9.The orthopedic prosthetic joint as set forth in claim 7 wherein the PEEK bearing comprises a layer of pure PEEK coated, molded or grafted onto a solid or porous polymer composite substrate.

    10.The orthopedic prosthetic joint as set forth in claim 7 wherein the PEEK bearing comprises a layer of pure PEEK coated, molded or grafted onto a solid or porous metallic substrate.

    11.The orthopedic prosthetic joint as set forth in claim 7 wherein the PEEK bearing comprises a layer of pure PEEK coated, molded or grafted onto a solid or porous ceramic or ceramic composite substrate.

    12.The orthopedic prosthetic joint as set forth in claim 7 wherein a bone contacting surface has a porous PEEK layer for bone ingrowth.

    13.The orthopedic prosthetic joint as set forth in claim 7 wherein the polyethylene has been cross-linked by irradiation.

    14.An orthopedic prosthetic joint according to claim 1, substantially as described herein with reference to the accompanying figures.

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