Polyethylene on metal/ceramic is the classic "low friction principle"of John Charnley. Some 60 years ago he introduced different materials to reduce friction and material wear. This principle is still alive today.

Varied materials also take into account shock absorption.  I've a attached a pdf that you may find interesting.

http://www.boneandjoint.org.uk/highwire/filestream/13706/field_highwire_article_pdf/0/807.full-text.pdf

The components have different roles and there's no universal material providing balance of resistance to compression and shear whilst being suitably low friction.

Dear colleagues, 

I would like to know your opinion about the metal on metal THA prostheses. I wonder over their popularity during the last 15 years, only to find that current reports demonstrate their higher rate of material wear. And, of course, to be witness of some sort of disappointment. Why in medical practics there exists this ondulating curve of oblivion and rediscovery of methods and devices in periods of 15-20  years ? 

Mr. Tanchev,

The Frauenhofer Institute has been working on a great solution,

"The hip socket is made of carbon fibre-reinforced PEEK – a high-strength, wear resistant, biocompatible polymer composite. For the femoral head, ceramic was used. In addition to this, a hydroxylapatite coating at the interface to the bone helps ensure that the bone tissue will fuse thoroughly with the surface structure of the implant"

see topic 4

http://www.fraunhofer.de/content/dam/zv/en/press-media/2012/PDFs/Research-news-05-2012.pdf

Thank you, Dr. McCormack. 

The conventional polyethylene (even HD) is the weak point of the varied material prosthesis because of the material  wear with the time. So the carbon fibre-reinforced PEEK hip socket could be a solution. 

Just Jeff will do.  I worked 10 years as Pedorthist and it was paramount to have proper acumen of the variety of conditions clients would present with in order to fashion proper foot orthoses.  I also sent off an email to inquire on which stage that Frauenhofen project is in, as its dated 05-2012.  This morning I also checked some unrelated bio-orthopaedic theories on tissue and osteogeneration to attempt to circumnavigate the need for a THA, it looks still very much on the blackboard.  As a favour too I've been summarizing articles on Methicillin-Resistant Staphylococcus aureus vulnerabilities.  By the looks of it Dr. Schwarz and Varrone from the  University of Rochester Medical Center Orthopaedic Dept may have it beat.  Incredible the varied avenues researchers have been approaching this bacteria,  It's somewhat related as it leads to osteomyelitis,

Now this is a fascinating read, Ross Hauser MD, The Regeneration of Articular Cartilage with Prolotherapy

http://www.prolotherapy.com/Hauser_Regeneration%20of%20Articular%20Cartilage%20with%20Prolotherapy.pdf

Jeff, really, prolotherapy seems to be very attractive. But to my best knowledge the evidence over its efficacy is in a tentavie phase.

There's great promise in regenerative medicine though,  I heard about Dr. S. Badylak  and the application of extracellular matrix for regrowth of a partially severed distal phalanx in 2008 on the BBC website.  http://news.bbc.co.uk/2/hi/health/7376191.stm and have been interested ever since. 

Stephen Badylak Laboratory

http://www.mirm.pitt.edu/badylak/

I think the best way is to use the FGM (Functionally graded Materials) for both Tibial and Femoral. I suggest the best Mats. for the FGM are metallic like Ti and ceramic like UHMWPE. One side of the component is Ti and the other side is UHMWPE and between them mixed of Ti and UHMWPE depend on the volume fraction for each other. The use of Ti is to withstand the load and resist the fracture. The use of UHMWPE  is excellent for wear. Therefore, it can provide balance of resistance to compression and shear whilst being suitably low friction. Also you can optimize the volume fraction for each Mat. in order to match the mechanical properties of natural joint . This generation of this material is called advanced composite materials and it's a new one. However, you can search about this technique at my Researchgate website.

With my best wishes 

Dr. Hedia, 

Your answer is very interesting. Thank you. We may only wait for some prospective controlled studies with long-term results.

Sorry, but @Hassan Sayed Hedia IS ABSOLUTELY WRONG about titanium and ceramic knee implant components. Titanium is NEVER used as a bearing surface in either hip or knee replacements. It does not have sufficient wear resistance.

Titanium is used in implant components which interface with bone, for its low elastic modulus (better load transfer) and excellent biocompatibility. The main bearing surfaces used in knees and hips is still the old standard--a Co-Cr-Mo-Ni alloy, articulating against UWMWPE (ultra high molecular weight polyethylene).

For people with Ni allergies, a zirconium alloy component is available from Smith and Nephew. Its surface is treated to create a hard wear-resistant oxide layer. These components are sold under the trade name "Oxinium." 

Other than the zirconium metal oxide-surfaced Oxinium, there are NO ceramic knee implant articulating surface components. In the hip there are oxides (principally alumina) femoral head balls, and also some designs having both a ceramic ball and a ceramic acetabular cup. The mechanics of the hip make use of ceramics possible, in spite of their brittleness. 

SORRY A.U. Daniels, BEFORE YOU SAID THAT ANSWER OF HASSAN HEDIA IS COMPLETELY WRONG, YOU Should UNDERSTAND WHAT I MEAN.

Sorry agin, A.U. Daniels, I am not said that the Ti is used as a bearing surface in either hip or knee replacements.   All the two surface of the tibial and Femoral for Knee replacement are UHMWPE. The other sides for the tibial and Femoral are Ti Or Stainless Steel. I think you haven't any Idea about the FGM. The Ti surface is used to resist any fracture of the component start form UHMWPE surface for both tebial and femoral. You should understand that, for example, the tibial surfaces are one surface is  UHMWPE  which is responsible for the wear and the second surface is Ti which is responsible for the resist the load and then the fracture and it is used at the interface with bone in order to reduce Stress Shielding. Therefore, the bearing surfaces, for Knee replacement, are UHMWPE (for tibial surface) and also UHMWPE for femoral component.   The Ti surface is used at the interface with bone, for its low elastic modulus (better load transfer) and excellent biocompatibility.

Nots, you can use Stainless steel instead of Ti or you can use a Co-Cr-Mo-Ni alloy instead of UHMWPE.

ARE YOU UNDER STAND WHAT I MEAN A.U. Daniels? PLEASE ANSWER

@Hassan Sayed Hedia - Part of the problem may be your difficulty with writing in English. However you still have said things that are completely wrong. For example, you now wrote that:

"All the two surface of the tibial and Femoral for Knee replacement are UHMWPE." 

That is simply not correct. The tibial bearing surface is UHMWPE, and the femoral bearing surface is Co-Cr-Mo-Ni alloy or occasionally zirconium metal with hard zirconium oxide outermost layer. 

On the tibial side, it is of course true that the UHMWPE bearing surface component is often (but not always) supported by a titanium component which interfaces with bone. This is for the reasons I previously stated, and which you repeated. 

Please don't try to lecture me about the selection of materials for use in total joint prostheses, their chemical and mechanical properties, and the consequent reasons for their selection and use. I have been working in this area since the 1970s. Take a look through my publications on ResearchGate, or I can send you pdf copies if some pertinent papers of mine if you like. 

@ A.U. Daniels, I also said at last sentence in the paragraph that  you can use a Co-Cr-Mo-Ni alloy instead of UHMWPE. I can lecture you because no any scientific bigger than the science and I think this is the big problem for you because you see your self as the biggest one . I think  you don't understand the techniques of FGM. Please try to read about FGM. I know you can't read because you are depend on your students. So, I can come to lecture you if you want.

Swiss are tough my brother Mark is one.

@Jeffrey McCormack, Thank you very much for your supporting.

@ A.U. Daniels You have two ways in order to stop our discussions:-

The first way is to send me an invitation in order to come to lecture you. In addition,

You will pay the Ticket, accommodation and you will pay a pocket money for me around 12000$ per day. If you accept, I will decide to come to you or not.

The second way is to send me apologize.

I am waiting hear from you.

@Hassan Sayed Hedia: 

I have kept a copy of your demands and your threat to continue to harass me unless I meet your demands. If you persist, I will report you to Research Gate.  

@ A.U. Daniels

My demand is published not a secret. It is not the threat and also not the harass. It just when you answer about any question you must be Kind. Please send me apologize. If you don't send me apologize I will report you to Research Gate.  

I think that the answer of Prof. Hassan Hedia is good answer. However, the answer of A.U. Daniels about Hedia's answer is completely wrong.  

Obviously, there are different opinions, different schools, different approaches. In my opinion a scientific discussion could be hard, but it shoud not abandon the good academic tone. And it seems to me this is the case here. The best solution here should be this discussion to be closed.

@Panayot Tanchev,  Of course, I agree with you. I close this discussions. Thanks a lot Dr.  Panayot Tanchev

Mr. Harsha asked specific about knee arthroplasty:

Indeed there have been a few attempts in the 50-s ans 60-s to use either PE or metal components only. All those ended in a catastophe and at ENDO-Klinik we had taken out a lots of them. The foto-archive there and museum will show many piece like that. The movements and weight bearing in the knee will never-I believe- able to manage with metal-metal or PE-PE components. PE there has the function to work as a shock absorber. The metal as the strong holder. Without this pairing a knee arthroplasty would not be possible. Maybe in future instead of PE a still better material can take its place.

I would like to thank everyone for their expert opinion and views on this topic. As Mr.Tanchev said, the argument aroused due to different school and different opinion. It was good to see two completely different views and different school views. It shows the competitiveness among people in the field of science and medicine, with the sole intension of bringing about improvement in the field.

We  have two different views to ponder upon and come to a conclusion.

Thanks again to everyone for taking time out to share their opinion and knowledge.

i am going to answer the question as an orthopaedic surgeon. A total knee arthroplasty is composed of many components as the knee joint has  three compartments. The femoral part of prosthesis, the tibial part that is the tibial tray and the polyrthylene insert. There is also the patella that many surgeons use a polyrthylene pateelar component. Usually the metal alloys that are used is either Titanium or cobalt chromeor cceramic. The latest type of polyeyhylene used is the coss linked or the highly cross linked. All what a surgeon wants from an arthroplasty is to have the different components adhere well to the bone, and to have the minimum  release of metal or polyethylene ions from the implants used. ceramic is also used in arthroplasty where it has the least coefficient friction and a combination of ceramic and ceramic or ceramic on polyethylene has the least release of metal ions to different parts of the body.

Dear Fares, Can you name a ceramic/ceramic total knee and some literature about survival rate?