Ceramic Implant Evaluations and OXINIUM Technology Joint Replacement with Oxidized Zirconium Bearing Components

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Caren Cooper
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1 Gordon Hunter, Ph.D. April 2017 Ceramic Implant Evaluations and OXINIUM Technology Joint Replacement with Oxidized Zirconium Bearing Components Trademark of Smith & Nephew.

Patient Trends Younger and living longer Shifting from pain relief to function recovery Increasing BMI Growth of emerging market More cost sensitive * * *Australian Orthopaedic Association National

2 Patient Trends Younger and living longer Shifting from pain relief to function recovery Increasing BMI Growth of emerging market More cost sensitive * * *Australian Orthopaedic Association National Joint Replacement Registry Annual Report. Adelaide: AOA: Figure has been reproduced in exact and complete form. For a full copy of the AOA National Joint Replacement Registry report, see 6%20Shoulder%20Arthroplasty

3 Metal Wear Issues Abrasive and oxidative wear roughen CoCr Bone cement Hip** Peak Knee*** Condyle Surface Bone Fretting debris Valley Shed in-growth particles Clinically observed scratches can increase wear* *Fisher et al., Proc. IME (H) 1995 **Barrack et al., Orthopedics 2002 ***Levesque et al., ORS 1998

Ceramic Performance: Testing for Registrations and Users Biocompatible Durable with stable properties Sufficient strength (tensile, fatigue) Low particle and ion release Lower articular friction

4 Ceramic Performance: Testing for Registrations and Users Biocompatible Durable with stable properties Sufficient strength (tensile, fatigue) Low particle and ion release Lower articular friction Decreased articular abrasion Less fretting corrosion Safe and clinically effective Risk for chipping or breaking* Geometry limitations** Zirconia Toughened Alumina*** *Tateiwa et al., Am J Orthop 2008 **Skinner, CORR 1999 ***Heiner et al., JBJS Case Connect 2014

homogeneity, and integrity* Poly wear of

Coating Original Surface Metal Substrate

5 Issues with Ceramic Coatings Deposited ceramic may not have uniformity, homogeneity, and integrity* Poly wear of ceramic coating may not be less than with metal (CoCr)** Ceramic Deposition New Surface Worn Off Ceramic Coating TiNbN Coating Original Surface Metal Substrate *Hunter et al., Medical Device Materials 2004 **Haider et al., ORS 2008

6 Oxidation of Zirconium Alloy* Wrought alloy is made of zirconium and niobium, which are passive and non-essential metal elements Metal alloy device is heated in air Surface transforms to stable oxide ceramic (~5 mm thick); not coated Oxide is durable and low-friction with toughness of metal Oxygen Diffusion Zr-2.5%Nb Alloy Air *Hunter et al., J ASTM Intl 2005 Original Surface Oxygen Enriched Metal Ceramic Oxide Oxygen Enriched Metal Metal Substrate 500 o C

7 High Integrity and Stable Oxide Has brick-like refined grain structure perpendicular to surface Does not have pores or segregation internally or at interface TEM Image* Ceramic Oxide Metal Alloy Rectangular Monoclinic Crystals of Zirconia *Hobbs et al., J Appl Ceram Tech 2005

a head** Zirconia Ox. Zirc. **Sprague et al.

8 Resilient Strength Supports 4.4 kn (1000 lbf) dynamic load on one condyle equivalent to CoCr* Does not shatter with 89 kn (10 ton) load on a head** Zirconia Ox. Zirc. **Sprague et al., ISTA 2003 *Tsai et al., SFB 2001

9 Uniform Oxide Thickness on All Shapes* Made with same designs as CoCr hips and knees *Hunter et al., J ASTM Intl 2005

10 Increased Surface Hardness Increases surface hardness over 2X that of CoCr* Aids adherence by oxygen enrichment *Long et al., SFB 1998

11 Durable Oxide Reduces abrasion by bone cement over 4900X Reduces post-test roughness over 160X Represented 10 years of cement debris in joint* *Hunter and Long, WBC 2000 CoCr Ox. Zirc.

12 Reduced Friction Attracts joint fluids better than metals do* Slides with less resistance against polyethylene** CoCr Ox. Zirc. 76.5º *Salehi et al., ISTA 2005 **Poggie et al., ASTM STP º

13 Less Polyethylene Wear in Laboratory Simulators Reduces wear rate under typical and severe conditions - Hip Simulator Example* - Knee Simulator Example** *Parikh et al., ORS 2013 **Ezzet et al., ORS 2006

14 Reduced Taper Fretting Corrosion Resists fretting corrosion in accelerated cyclic loading* CoCr Ti64 Exhibits less fretting corrosion of clinically retrieved heads** Ti64 CoCr Ox. Zirc. OxZr **Cartner et al., ORS 2014 *Pawar et al., ASMI 2004

15 Excellent Survivorship in Knees Sold over 925,000 knees since December 1997 Achieved 97.8% implant survivorship in 10 year clinical study for 83 patients* *Innocenti et al., The Knee 2014

fewer features; inserts 31% fewer features Roughness measured by non-contact profilometry;

16 Fewer Clinical Knee Wear Features Produced lower wear scores for both surfaces in 1-3 year retrieval study* Retrieved component pairs matched for time and patient factors Femurs 92% fewer features; inserts 31% fewer features Roughness measured by non-contact profilometry; all parameters were less CoCr *Heyse et al., The Knee 2011; Heyse et al., CORR 2014 OxZr

17 Unsurpassed Survivorship in Hips Sold over 500,000 hips since October 2002 Achieved 96.8% implant survival rate at 10 years in AOA registry* Comparing the cumulative revision rates for these bearings, ceramicised metal/xlpe has the lowest rate of revision. As in previous years, the Registry urges caution in the interpretation of this result. This bearing is a single company product used with a small number of femoral stem and acetabular component combinations. This may have a confounding effect on the outcome, making it unclear if the lower rate of revision is an effect of the bearing surface or reflects the limited combination of femoral and acetabular prostheses. *Australian Orthopaedic Association National Joint Replacement Registry Annual Report. Adelaide: AOA: Figure has been reproduced in exact and complete form. For a full copy of the AOA National Joint Replacement Registry report, see

Conclusion Patient trends pose challenges for articular

may address these needs Laboratory and clinical studies are

zirconium technology exhibits desired characteristics Low

18 Conclusion Patient trends pose challenges for articular implant longevity Ceramic implants have characteristics that may address these needs Laboratory and clinical studies are used to evaluate implant characteristics OXINIUM oxidized zirconium technology exhibits desired characteristics Low particle and ion release Strong without being brittle Durable with stable properties

The perfect equation for hips

The perfect equation for hips OXINIUM Oxidized Zirconium (proprietary ceramicised metal) + = XLPE (Smith & Nephew unique formula) VERILAST for Hips (Smith & Nephew Technology) Ceramicised metal has unmatched