Stryker's New Mobile Bearing Hip Solution Marks Advancement in Large Head Technology

MAHWAH, N.J., March 10 /PRNewswire-FirstCall/ -- Stryker Corporation's (NYSE: SYK) Orthopaedics Division today announced the release of the ADM X3 Mobile Bearing Acetabular System, a next-generation technology for hip replacement surgery designed to minimize the risks associated with total hip replacement surgery.

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While total hip replacement is one of the most successful surgical procedures performed today, dislocation remains one of the top reported complications(1).  To address dislocation, conventional designs focus on the use of metal-on-metal large head technologies which based on recent studies suggest added risk due to metal ion release(2).  Combining an evolution in design with the only anatomic dual mobility acetabular system and its patented X3 Advanced Bearing Technology(3), Stryker Orthopaedics Mobile Bearing Hip addresses dislocation without the risk of metal ion release.

"By developing an implant that addresses adverse outcomes associated with hip replacement surgery, we are not only helping surgeons to treat their patients more successfully, but we are also striving to reduce global healthcare costs by minimizing surgical complications," said Bill Huffnagle, Vice President and General Manager of Hip Reconstruction at Stryker Orthopaedics.

This Mobile Bearing Hip system is made possible due to Stryker Orthopaedics' patented X3 Advanced Bearing Technology(3) which is designed to increase the longevity of the implant. Laboratory tests have shown a 97% reduction in volumetric wear compared to conventional polyethylene(4). ADM's anatomic design also has the potential to increase mobility and reduce groin pain(5),(6). Its dual points of articulation help accommodate multi-directional movement, which provide greater range of motion than fixed implant designs based on laboratory testing(5).  In addition, the anatomic cup design has an iliopsoas tendon cut-out aimed at reducing iliopsoas tendon impingement(6), a key cause of post-operative groin pain.

The introduction of ADM with X3 signals Stryker Orthopaedics' intention to lead the market in the mobile bearing hip category with a product that addresses the limitations of other hip products in the market today.  The launch also highlights the deep commitment and significant investments Stryker is making in its hip business -- ADM X3 is the third major hip product launch by Stryker in the past year.  

"We are committed to offering advanced technologies that benefit both surgeons and patients while adding value in ways that have the potential to reduce costs to the healthcare system," said Huffnagle.  

About Stryker Orthopaedics

Stryker Orthopaedics is a division of the Stryker Corporation, one of the world's leading medical technology companies. Stryker Orthopaedics offers an extensive orthopaedic product portfolio including hip, knee and upper extremity reconstructive devices, bone cement, trauma implants, bone substitutes and spine systems. For more information about Stryker Orthopaedics, visit: http://www.stryker.com/enus/products/Orthopaedics/index.htm.

(1) Berry, D., et al. (2005). Effect of Femoral Head Diameter and Operative Approach on Risk of Dislocation After Primary THA. JBJS 87-A(11): 2456-2463.

(2) Crawford, R., Ranawat, C. S., Rothman, R. H. (2010). Editorial: Metal on Metal: Is It Work the Risk? JOA 25(1): 1-2.

(3) US Patent # 6,174,934, 6,372,814, 6,664,308, 6,818,020, 7,517,919.  

(4) Stryker Orthopaedics Trident Acetabular Inserts made of X3 UHMWPE (unsterilized), 721-00-32E, show a 97% reduction in volumetric wear rate versus the same insert fabricated from N2\Vac gamma sterilized UHMWPE, 620-00-32E. The insert tested was 7.5mm thick with an inner diameter of 32mm. Testing was conducted under multi-axial hip joint simulation for 5 million cycles using a 32mm CoCr articulating counterface and calf serum lubricant. X3 UHMWPE Trident acetabular inserts showed a net weight gain due to fluid absorption phenomena but yielded a positive slope and wear rate in linear regression analysis. Volumetric wear rates were 46.39 +/- 11.42mm3 /106 cycles for N2\Vac gamma sterilized UHMWPE inserts and 1.35 +/- 0.68mm3/106 cycles for X3 UHMWPE (unsterilized) Trident Acetabular Inserts. Although invitro hip wear simulation methods have not been shown to quantitatively predict clinical wear performance, the current model has been able to reproduce correct wear resistance rankings for some materials with documented clinical results. d, e, f.

• d. Wang A. et al. Tribology International, Vol. 31, No. 1-3:17-33, 1998.
• e. Essner A. et al. 44th Annual Meeting, ORS, New Orleans, Mar. 16-19, 1998:774.
• f. Essner A. et al. 47th Annual Meeting, ORS, San Francisco, Feb. 25-28, 2001:1007.

8. X3 UHMWPE maintains mechanical properties after accelerated oxidative aging. No statistical difference was found for Tensile Yield Strength, Ultimate Tensile Strength and Elongation as measured per ASTM D638 before and after exposure to ASTM F2003 accelerated aging (5 Atmospheres (ATM) of oxygen at 70 degrees C for 14 days). Tensile Yield Strength was 23.5 +/- 0.3 MPa and 23.6 +/- 0.2 MPa, Ultimate Tensile Strength was 56.7 +/- 2.1 MPa and 56.3 +/- 2.3 MPa and Elongation was 267 +/- 7% and 266 +/- 9% before and after accelerated oxidative aging, respectively.

9. X3 UHMWPE resists the effects of oxidation. No statistical difference was found for Tensile Yield Strength, Ultimate Tensile Strength, Elongation, Crystallinity and Density as measured per ASTM D638, D3417 and D1505 before and after ASTM F2003 accelerated aging (5ATM of oxygen at 70 degrees C for 14 days). Tensile Yield Strength was 23.5 +/- 0.3 MPa and 23.6 +/- 0.2 MPa, Ultimate Tensile Strength was 56.7 +/- 2.1 MPa and 56.3 +/- 2.3 MPa, Elongation was 267 +/- 7% and 266 +/- 9%, Crystallinity was 61.7 +/- 0.6% and 61.0 +/- 0.5%, and Density was 939.2 +/- 0.1 kg/m3 and 939.2 +/- 0.2 kg/m3 before and after accelerated oxidative aging, respectively.

(5) Stryker Test Report: RD-06-078.

(6) Tracol P., Vandenbussche E., Deloge N., et al. (2007). Navigation Acetabular Anatomic Study Application in the Development of a New Implant. EFORT Poster.

SOURCE Stryker Orthopaedics