Verilast Technology Powerpoint

VERILAST™

Technology with LEGION™

Primary Knee System

Based on in-vitro wear simulation testing, the LEGION Primary Knee System with VERILAST technology is expected to provide wear performance sufficient for 30 years of actual use under typical conditions. The results of in-vitro wear simulation testing have not been proven to quantitatively predict clinical wear performance. Also, a reduction in total polyethylene wear volume or wear rate alone may not result in an improved clinical outcome as wear particle size and morphology are also critical factors in the evaluation of the potential for wear mediated osteolysis and associated aseptic implant loosening. Particle size and morphology were not evaluated as part of the testing. ™Trademark of Smith & Nephew.

Presenter

Smith and Nephew has an industry exclusive wear claim for our VERILAST Technology. Smith and Nephew is now the only company that has done the testing and development to try and answer the patient’s and physician’s question “how long should my knee last before it wears out?”

Sharkey et a l, Why Are Tota l Knee Arthroplasties Failing Today? CORR; Number 404, pp. 7–13 2002

Reasons for Revision

Peter F. Sharkey, MD; William J. Hozack, MD; Richard H Rothman, MD, PhD; Shani Shastri,

MD; and Sidney M. Jacoby, BA

Presenter

In this Insall Award Winning paper from Dr. Sharkey et al in 2002, the authors looked at the causes of revision for all revisions over a 3 year period.

Sharkey et a l, Why Are Tota l Knee Arthroplasties Failing Today? CORR; Number 404, pp. 7–13 2002

Reasons for Revision

™Trademark of Smith & Nephew. Reg. US Pat. & TM Off. All Trademarks acknowledged.

Presenter

While there were many reasons cited for both early (<2 years) and late (>2 years) revisions, the largest reason for revision cited by the authors was wear of the polyethylene. PE wear was identified as the cause of 44% of the late revisions.

Improving wear

Poggie et a l., ASTM STP 1145 Asano et al. Dose Effects of Cross-Linking Polyethylene for Tota l Knee Arthroplasty on Wear Performance and Mechanica l Properties J Biomed Mater Res Part B: Appl Biomater 83B: 615–622, 2007

UHMWPE Wear rate and Radiation


VERILAST™ Technology in the LEGION™ Primary Knee System was tested for 30 years of simulated wear performance

Ave

rage

vol

umet

ric w

ear (

mm

3 )

Comparison of the mean volumetric wear of the CoCr/CPE and VERILAST couples after simulating 3 years of use.

120

Simulation of 3 yearsVERILASTCoCr/CPE

100

80

60

40

20

0

160

140120.42

98%

2.67

p<0.01

Ave

rage

vol

umet

ric w

ear (

mm

3 )

Based on in-vitro wear simulation testing, the LEGION Primary Knee System with VERILAST technology is expected to provide wear performance sufficient for 30 years of actual use under typical conditions. The results of in-vitro wear simulation testing have not been proven to quantitatively predict clinical wear performance. Also, a reduction in total polyethylene wear volume or wear rate alone may not result in an improved clinical outcome as wear particle size and morphology are also critical factors in the evaluation of the potential for wear mediated osteolysis and associated aseptic implant loosening. Particle size and morphology were not evaluated as part of the testing. ™Trademark of Smith & Nephew. Certain marks Reg. US Pat. & TM Ofc.

Presenter

In a test which simulated 3 years of activity comparing the conventional materials of Cobalt Chromium and conventional polyethylene to VERILAST Technology in the LEGION Knee, the knees with VERILAST Technology demonstrated 98% less wear than the knees with conventional materials. This testing design was based on the Leeds protocol which was developed on the kinematics of younger patients (average age 27.2) has higher amounts of internal and external rotation and AP translation than the widely used ISO protocol and was adopted to better reflect the higher demand of younger patients.

22.78

Ave

rage

vol

umet

ric w

ear (

mm

3 )

30 years Simulation3 years Simulation


120

Comparison of the mean volumetric wear of the CoCr/CPE after simulating 3 years of use and VERILAST after simulating 30 years of use.

VERILASTCoCr/CPE

100

80

60

40

20

0

160

140120.42

p<0.01

81%


Presenter

Upon continued testing of the LEGION Cruciate Retaining (CR) knees with the VERILAST Technology for 45 million cycles, enough to approximate 30 years of use, and comparing the data to the testing of the knees with conventional materials which simulated only 3 years of use, the LEGION CR knees with VERILAST Technology still showed significantly lower wear (81% lower). The results of this unprecedented testing represents significant improvements in wear performance and led to an industry exclusive 30 year wear claim.

25

15

20

10

0

-5Mea

n vo

lum

etric

wea

r XLP

E in

sets

(mm

3 ) 35

30

5

Duration Simulation (years)6 9 15.512 19 2622.5 303



Presenter

While understanding the overall wear rate is critical to the overall performance, in a test of this duration, it is necessary to measure the wear performance throughout the test to understand how the materials are performing. In the past, materials have performed very well in the short term, but in the longer periods of use developed a condition commonly referred to as “run away wear.” As can be seen from these data, the wear rate of the LEGION CR knees with VERILAST Technology demonstrated a very consistent, linear rate which is consistent with stable performance.

Duration Simulation (years)

8.0

6.0

7.0

5.0

4.0

3.00 63 9 15.512 19 2622.5 30

Oxi

de T

hick

ness

(!m

)VERILAST™ Technology in the LEGION™ Primary Knee System was tested for 30 years of simulated wear performance


Presenter

Equally important during testing was the performance of the award winning, abrasion resistant OXINIUM Technology. Throughout the testing frequent measurements were taken of the oxide thickness to evaluate if the oxide was being affected in any way or perhaps wearing away. As seen in the data, the change in oxide thickness was negligible throughout the 30 year simulation and any change that may have occurred was below the testing limit of 0.2 microns.

VERILAST™ Technology demonstrates lower wear rates than other XLPE formulations using similar test conditions

Conventional Material Technologies

XLPE Material Technologies

1. H. M. J. McEwen, P. I. Barnett, C. J. Bell, R. Farrar, D. D. Auger, M. H. Stone and J. Fisher, “The influence of design, materials and kinematics on the in vitro wear of total knee replacements,”J Biomech, 2005;38(2):357-365.

2. A. Parikh, M. Morrison and S. Jani, “Wear testing of crosslinked and conventional UHMWPE against smooth and roughened femoral components,” Orthop Res Soc, San Diego, CA, Feb 11-14, 2007, 0021.3. AA. Essner, L. Herrera, S. S. Yau, A. Wang, J. H. Dumbleton and M. T. Manley, “Sequentially crosslinked and annealed UHMWPE knee wear debris,” Orthop Res Soc, Washington D.C., 2005, 71.4. L. Herrera, J. Sweetgall, A. Essner and A. Wang, “Evaluation of sequentially crosslinked and annealed wear debris,” World Biomater Cong, Amsterdam, May 28-Jun 1, 2008, 583.5. C. Schaerer, K. Mimnaugh, O. Popoola and J. Seebeck, “Wear of UHMWPE tibial inserts under simulated obese patient conditions,” Orthop Res Soc, New Orleans, LA, Feb 6-10, 2010, 2329.6. Biomet publication, “FDA Cleared Claims for E1 Antioxidant Infused Technology,” http:/ /www.biomet.com/orthopedics/getFile.cfm?id=2657&rt= inline7. R. Papannagari, G. Hines, J. Sprague and M. Morrison, “Long-term wear performance of an advanced bearing knee technology,” ISTA, Dubai, UAE, Oct 6-9, 2010.

™Trademark of Smith & Nephew. All Trademarks acknowledged.

Presenter

As seen from the wear rates from several published reports using very similar protocols, conventional materials produce wear rates that are fairly equivalent across several implant designs, XLPE technologies produce significantly lower wear rates than conventional materials, but still fairly similar rates across implant designs, and VERILAST Technology demonstrates another significant improvement in wear rates. Only Smith and Nephew offers VERILAST Technology.

VERILAST!

Technology


Concept

Two major bearings components in TKA

• Hard metallic femoral component

• Soft polyethylene tibial component

Need a system-wide solution

VERILAST™ Bearing Technology

• Provides lowest wear combination

• OXINIUM™ femoral component

– Provides lower wear than CoCr

– Maintains low wear of XLPE

• XLPE tibial insert

– Provides higher performance than CPE


Hard bearings–OXINIUM™ Oxidized Zirconium

• History

• Properties

• Performance


The history – OXINIUM™ Oxidized Zirconium

• Award Winning Technology– ASM International

• First Implant in 1997

• > 300,000 implants


OXINIUM™ material properties

• Surface transformed ceramic

– Not a coating

• Toughness of metal and wear resistance of ceramic

• More wettable than CoCr

– Less friction than CoCr

– Reduces wear of poly

• Surface 2x harder than CoCr alloy

– More scratch resistant

• Nickel content less than 35 ppm

– For metal-sensitive patients

Metal Substrate

Oxygen Enriched MetalOriginal Surface

Air500oCOxygen

Diffusion

Ceramic Oxide

Oxygen Enriched Metal


Metal sensitivity

• 56 yo homemaker

– Cannot wear jewelry

• 3 yr post CoCr TKA

– Pain, stiffness

– Persistent rash

• Revised to alumina

– Rash resolved

• Contra-lateral TKA

– OXINIUM™ material used

– No sensitivity issues

Nasser et a l., AAOS, San Diego, CA, 2007, 437 ™Trademark of Smith & Nephew. Reg. US Pat. & TM Off. All Trademarks acknowledged.

Hardness – Surface of OXINIUM™ material is 2X that of CoCr

*Long et al., SFB 1998


Abrasion resistance

Hunter and Long, WBC 2000

4900 times less volumetric wear in bone cement abrasion test compared to CoCr


Microabrasive performanceCoCr vs. OXINIUM™ Material Retrieved at 30 months

CoCr OXINIUM™

Alloy


Strength and toughness

• Behaves like metal

• Supports 1000 lbf fatigue load for 10 Mc

– Similar to CoCr

• Condyle bent at 4500 lbf

– No fracture

– No oxide delamination


Coefficient of friction

• Lower coefficient of friction against polyethylene and against cartilage

• Lower coefficient of friction means less adhesive wear

Poggie et al., ASTM STP 1145™Trademark of Smith & Nephew. Reg. US Pat. & TM Off. All Trademarks acknowledged.

OXINIUM™ alloy on CPE wear performance

• OXINIUM alloy provides improved wear performance

– Under pristine conditions

– Due to lower friction of ceramic surface

• OXINIUM material maintains improved wear performance

– Under microabrasive conditions

– Scratch resistance due to improved hardness

50%50%


Soft bearing


Soft bearing

• Hip– More conforming

– Lower contact stresses

– Primarily sliding motion

• Knee– Less Conforming

– Higher contact stresses

– Complex sliding and rolling motions

• Requires different crosslink formulations


TKA Crosslinked PE Market

MaterialGURResin

Dose(Mrad)

ThermalTreatment Sterilization

FreeRadicals? Oxidation?

Smith & NephewXLPE 1020 7.5 Re-melt EtO No No

DePuy XLK 1020 5 Re-melt Gas Plasma No No

Zimmer Prolong 1050 6.5 Re-melt Gas Plasma No No

BiometE-Poly / E1 1020 10+3 Sub-melt +

Vit E Diffusion Gamma-Inert Yes No

Stryker X3 1020 9 = 3×3 Sub-melt Gas Plasma Yes Yes


The right amount?

“Although a certain amount of cross-linking would be effective for clinical application of PE tibial inserts, an optimal radiation dose should be much smaller than that used in current XLPE in total hip arthroplasty.”1

Asano et al. Dose Effects of Cross-Linking Polyethylene for Tota l Knee Arthroplasty on Wear Performance and Mechanical Properties J Biomed Mater Res Part B: Appl Biomater 83B: 615–622, 2007


Asano et al. Dose Effects of Cross-Linking Polyethylene for Tota l Knee Arthroplasty on Wear Performance and Mechanical Properties J Biomed Mater Res Part B: Appl Biomater 83B: 615–622, 2007


The right amount

Crosslinking and wear


Knee simulator wear


Knee simulator wear


Microabrasive performanceCoCr vs. OXINIUM™ Alloy

CoCr OXINIUM


Knee simulator wear


TKA Crosslinked PE market

MaterialGURResin

Dose(Mrad)

ThermalTreatment Sterilization

FreeRadicals? Oxidation?

Smith & NephewXLPE 1020 7.5 Re-melt EtO No No

DePuy XLK 1020 5 Re-melt Gas Plasma No No

Zimmer Prolong 1050 6.5 Re-melt Gas Plasma No No

BiometE-Poly / E1 1020 10+3 Sub-melt +

Vit E Diffusion Gamma-Inert Yes No

Stryker X3 1020 9 = 3×3 Sub-melt Gas Plasma Yes Yes


Oxidative stability


Free radical concentration

1200

8900

2800

10

100

1000

10000

100000

S&N CPE S&N XLPE StrykerX3™ StrykerCrossfire™

Gamma-Air

FRC

(Tril

lion

Free

Rad

ical

s/g)

NotDetectable

NotDetectable

1. Wang et al, J Appl Phys, 2006, 39, 3213-32192. Muratoglu et al, Clin Orth Rel Res, 2003, 417, 253-262


VERILAST™ Technology demonstrates lower wear rates than other XLPE formulations using similar test conditions

1. H. M. J. McEwen, P. I. Barnett, C. J. Bell, R. Farrar, D. D. Auger, M. H. Stone and J. Fisher, “The influence of design, materials and kinematics on the in vitro wear of total knee replacements,”J Biomech, 2005;38(2):357-365.

2. A. Parikh, M. Morrison and S. Jani, “Wear testing of crosslinked and conventional UHMWPE against smooth and roughened femoral components,” Orthop Res Soc, San Diego, CA, Feb 11-14, 2007, 0021.3. AA. Essner, L. Herrera, S. S. Yau, A. Wang, J. H. Dumbleton and M. T. Manley, “Sequentially crosslinked and annealed UHMWPE knee wear debris,” Orthop Res Soc, Washington D.C., 2005, 71.4. L. Herrera, J. Sweetgall, A. Essner and A. Wang, “Evaluation of sequentially crosslinked and annealed wear debris,” World Biomater Cong, Amsterdam, May 28-Jun 1, 2008, 583.5. C. Schaerer, K. Mimnaugh, O. Popoola and J. Seebeck, “Wear of UHMWPE tibial inserts under simulated obese patient conditions,” Orthop Res Soc, New Orleans, LA, Feb 6-10, 2010, 2329.6. Biomet publication, “FDA Cleared Claims for E1 Antioxidant Infused Technology,” http:/ /www.biomet.com/orthopedics/getFile.cfm?id=2657&rt= inline7. R. Papannagari, G. Hines, J. Sprague and M. Morrison, “Long-term wear performance of an advanced bearing knee technology,” ISTA, Dubai, UAE, Oct 6-9, 2010.

™Trademark of Smith & Nephew. All Trademarks acknowledged.

Presenter

As seen from the wear rates from several published reports using very similar protocols, conventional materials produce wear rates that are fairly equivalent across several implant designs, XLPE technologies produce significantly lower wear rates than conventional materials, but still fairly similar rates across implant designs, and VERILAST Technology demonstrates another significant improvement in wear rates. Only Smith and Nephew offers VERILAST Technology.

Summary

• VERILAST™ Bearing Technology– Provides industry-leading wear performance

• OXINIUM™ Oxidized Zirconium femoral components– Surface transformed ceramic– ½ frictional forces of CoCr– 2x hardness of CoCr

• XLPE tibial inserts– 7.5 Mrad melt annealed– Undetectable free radical concentration– Oxidation resistant– Delamination resistant


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Verilast Technology Powerpoint