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X3 Advanced Bearing Technology

Preserving Strength

The structural strength of X3 Advanced Bearing Technology allows it to be applied to knee applications where abrasive, adhesive, and fatigue wear may be present due to a more cyclical motion pattern.1

Maintenance of mechanical strength allows X3 technology to be applied to tibial bearings that are subject to greater shear stresses such as posteriorly stabilized tibial inserts. These shear loads on the PS post create a moment arm to the locking mechanism, potentially increasing the stress on the polyethylene in the posterior region of the mechanism.2,3

X3 Advanced Bearing Technology maintains mechanical properties after accelerated oxidative age laboratory testing. No statistical difference was found for tensile-yield strength, ultimate tensile strength, and elongation.4,5

Stryker Corporation or its divisions or other corporate affiliated entities own, use or have applied for the following trademark(s) or service mark(s): X3. All other trademarks are trademarks of their respective owners or holders.
References

1. X3 UHMWPE resists the effects of oxidation. No statistical difference was found for Tensile Yield Strength, Elongation, Crystallinity and Density as measured per ASTM D638, D3417 and D1505 before and after ASTM F2003 accelerated aging (5 ATM of oxygen at 70ºC 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 +/- 0.1kg/m3 before and after accelerated oxidative aging, respectively.

2. 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 70ºC 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.

3. X3 UHMWPE resists the effects of oxidation. No statistical difference was found for Tensile Yield Strength, Elongation, Crystallinity and Density as measured per ASTM D638, D3417 and D1505 before and after ASTM F2003 accelerated aging (5 ATM of oxygen at 70ºC 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 +/- 0.1kg/m3 before and after accelerated oxidative aging, respectively.

4. X3 UHMWPE maintains mechanical properties for Tensile Yield Strength and Ultimate Tensile Strength of N2/Vac gamma sterilized UHMWPE as measured by ASTM D638. Tensile Yield Strength was 23.2 +/- 0.4 MPa and 23.5 +/- 0.3 MPa for N2/Vac UHMWPE and X3 UHMWPE, respectively. Ultimate Tensile Strength was 54.8 +/- 2.5 MPa and 56.7 +/- 2.1 MPa for N2/Vac UHMWPE and X3 UHMWPE, respectively.

5. Stryker Orthopaedics Scorpio CR tibial inserts made from X3 UHMWPE, 72-22-0708, show a 79% reduction in volumetric wear rate versus the same insert fabricated from N 2 Vac gamma sterilized UHMWPE, 72-2-0708. The insert tested was size 7, 8mm thick. Testing was conducted under multiaxial knee simulator (multi-station MTS knee joint simulator [1]) for five million cycles using appropriate size CoCr counterfaces, a specific type of diluted calf serum lubricant and the motion and loading conditions, representing normal walking, outlined in ISO/DIS 14243-3. Volumetric wear rates were 34.6 ± 1.5mm3/10 6 cycles for test samples. Test inserts were exposed to a gas plasma sterilization process. In vitro knee wear simulator tests have not been shown to quantitatively predict clinical wear performance.

[1] Essner, A.,Wang, A., Stark, C., and Dumbleton, J. H., “A Simulator for the Evaluation of Total Knee Replacement Wear,” 5th World Biomaterials Congress, Toronto, Canada,May 1996, pg. 580.