X3 - the launch of a new hard-wearing, soft-bearing joint technology

This year’s British Orthopaedic Association (BOA) Congress in Manchester (25th- 28th September 2007) will see the launch of a significant new development in joint replacement materials that could considerably increase the life of hip and knee replacements.

X3™ is a wear-resistant bearing material that has been specially developed from conventional polyethylene. This innovative material offers surgeons the first highly cross linked polyethylene bearing surface that keeps its structural strength, whilst reducing wear and eliminating the potential for oxidation.

The volumetric wear is reduced by 97% in the hip, making the wear rates similar to more expensive metal on metal bearings. However, in contrast to other highly crosslinked materials the wear particle size distribution also remains similar to that of standard polyethylene which could have implications for reducing osteolysis.

Dr John Dumbleton, one of the inventors of X3 for Stryker, explains:

“We have pioneered a unique manufacturing process which means the X3 plastic can resist wear under all conditions. In tests we have demonstrated wear reductions of 97% in the hip and 79% in the knee.

With increasing numbers of patients undergoing joint replacement surgery a material such as X3 has the potential to help reduce the number of joint revisions due to wear and tear, and could save precious NHS resources,” he said.

X3 is the only bearing material on the market to address the three major factors of strength, wear and oxidation that contribute to hip and knee replacement failure.  It can also be used in any patient unlike some other advanced bearing technologies.

X3 offers a particularly significant advance in knee replacement surgery. Knees are subjected to huge pressure and surgeons have been limited in their choice of bearing materials for knee replacements. A crosslinked polyethylene with no reduction in strength is a major breakthrough in this area.

Niall Flynn is a consultant knee surgeon at Portsmouth NHS Trust and Nuffield Hospital in Hampshire who has used X3 in a number of knee operations.

“I feel X3 is the most groundbreaking and dynamic development in knee replacement surgery in the last 15 years. It allows us to be confident in the survivorship of knee replacements in younger more active patients.

“As we see that knee replacements are changing throughout the country with younger patients demanding a better quality of life we can give them that with confidence using X3,” said Mr Flynn.

On Thursday 27th September Stryker is hosting a meeting at the Congress to discuss the impact of this next generation technology on the future of joint replacement.

The meeting is to be chaired by Mr. Fares Haddad and attended by Dr John Dumbleton and Dr Aiguo Wang, co-inventors of X3TM technology, Professor David Murray and Dr Wael Barsoum. There will be an opportunity to speak to Stryker’s X3 team as well as to the specialists in the field.


Notes to Editors

About X3

The X3 polyethylene process begins with Compression Moulded GUR 1020 polyethylene exposed to a sequentially irradiation and annealing process (heating plastic below the melting point) which leads to progressive crosslinking (creating stronger bonds between molecules), this is what gives X3 its superior wear resistance.  Other materials use a single, high dose of radiation followed by remelting. This recrystallises those materials and makes them weaker.

X3 polyethylene is the first highly crosslinked polyethylene to offer simultaneously:

a. Superior structural fatigue strength.

Conventional re-melting following irradiation of polyethylene significantly alters the structure, with up to a 35% drop in ultimate tensile strength and a 15% drop in yield stress.

In contrast, annealing (as used in the X3 process) following irradiation has been shown to maintain the crystal structure and preserve the strength of the material.

b. Greater wear reduction than first generation highly crosslinked polyethylene

X3 polyethylene has been shown to reduce the wear rate of tibial inserts in the knee by up to 79% compared to conventional polyethylene (Essner et al, Trans 51st ORS 2004).

In hips X3 has 97% reduction in wear in the hip over conventional (gamma-inert sterilised) polyethylene better than second generation crosslinked annealed polyethylene (Essner et al, Trans 51st ORS, 2004). 

Further hip simulator testing revealed that for X3 polyethylene wear did not vary significantly with head size or polyethylene thickness.

c. Oxidation resistance

X3 demonstrates higher oxidation resistance than conventional non-crosslinked polyethylene under extreme laboratory conditions (immersion in 5 atmospheres (ATM) of oxygen at 70 degrees centigrade for 14 days).  X3 maintains mechanical properties after accelerated oxidative age laboratory testing. No statistical difference was found for tensile-yield strength, ultimate tensile strength and elongation.

About Stryker

Stryker UK’s launch event is to be held on Thursday 27 September from 5.30pm at the BOA 2007 in Manchester, Charter Suite 3, Manchester Conference Centre.

Topics for discussion include:

Are all soft bearings equal?

X3: What’s the evidence?

X3 Technology in Hips: what are the benefits?

Wear in the knee: impact of knee design and advanced poly technology

Has the gold standard just got better? 

Invited speakers:

Dr John Dumbleton: Co-inventor of X3 technology and a materials scientist specialising in orthopaedic materials and tribology.

Professor David Murray: Consultant surgeon specialising in hip and knee replacement at the Nuffield Orthopedic Centre in Oxford.

Dr Wael Barsoum: is an Orthopaedic surgeon from the USA specialising in hip and knee surgery at the Cleveland Clinic Foundation.

Dr Aiguo Wang: Co-inventor of X3 technology and Vice President of Reconstructive Technologies at Stryker Orthopaedics. He holds 9 US patents and several international patents and has won three best invention awards during the past four years.

This is an invitation only event. Please contact Lucy Richardson at Stryker UK (lucy.richardson@stryker.com)

Stryker is a broadly-based global leader in medical technology who consistently delivers exceptional results. Through unparalleled variety of innovative, high-quality products alongside simplified techniques and improved hospital efficiencies, Stryker are reducing healthcare costs throughout the world and helping patients to regain their active lives. www.stryker.co.uk

Healthcare Republic does not have an editorial influence or input in to these press releases. The views expressed within these documents are not endorsed by Healthcare Republic or Haymarket Medical Publications Limited.

Enquiries should be directed to any contacts listed within the press releases.


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