Locking in life Evolution Conventional UHMWPE Evolution - PowerPoint PPT Presentation

Vitamin E Technology Locking in life

Evolution Conventional UHMWPE

Evolution Conventional UHMWPE Introduced by Sir John Charnley in 1962 Moderately cross-linked due to gamma sterilisation Outstanding mechanical properties: 50-60% crystalline Good bearing material High wear characteristics (leading to osteolysis)

Evolution Conventional UHMWPE Positive:  Good mechanical properties Negative:  High wear  Poor oxidation resistance

Evolution First generation HXLPE

Evolution First generation HXLPE – processing Consolidation of UHMWPE powder (GUR1020, GUR1050, etc) Irradiate (50kGy – 100kGy) cross-linking material Anneal to reduce free radicals Remelt to remove free radicals Machine consolidated form Package and sterilise (inert) - ETO

Evolution First generation HXLPE Cross linking improves wear characteristics In vitro and in vivo wear data corroboration for polyethylene acetabular components cross-linked at various radiation dose levels 1 1. Wang, 2009.

Evolution First generation HXLPE – oxidation  Occurs in vivo with either remelt or Absorption of lipids e.g. squalene  annealed polyethylene: Cyclic loading 10-year cross-fire liner 4-year in vivo X3 liner 10-year longevity liner 8,0 8,0 8,0 7,0 7,0 7,0 Oxidation Index (A.U.) 6,0 6,0 6,0 Oxidation Index (A.U.) Oxidation Index (A.U.) 5,0 5,0 5,0 4,0 4,0 4,0 oxidation: 45X↑ oxidation: 15X↑ oxidation: 2X↑ 3,0 3,0 cross-link density: 4X↓ cross-link density: 2X↓ cross- link density: 1.4X↑ 3,0 2,0 2,0 2,0 1,0 1,0 1,0 0,0 0,0 0,0 0,0 2,0 4,0 0,0 2,0 4,0 0,0 1,0 2,0 3,0 4,0 5,0 Depth (mm) Depth (mm) Depth (mm)

Evolution First generation HXLPE – concerns Rim fracture: Positive:  Tower et al ., JBJS 2007  Low wear  Furmanski et al ., AAOS 2008  Moore et al ., JBJS 2008 Negative:  Duffy et a l., JOA 2009  Oxidative degeneration In vivo oxidation:  Poor mechanical properties  Currier et a l., JBJS 2007  Kurtz et a l., CORR 2006  Muratoglu et al ., 2009

Evolution Next generation vitamin E HXLPE

Next generation vitamin E HXLPE E Vitamin E blended Locking out oxidation UHMWPE Ci C old i rradiated Locking out wear Ma M echanically a nnealed Locking in strength Locking in life

Next generation vitamin E HXLPE Vitamin E Locking E E blended out UHMWPE oxidation

Locking out oxidation Active stabilisation The vitamin E is grafted to the polyethylene:  acting as a reservoir for active stabilisation  preventing free radical oxidation into the long term Oxidation occurs through loading and absorption of lipids (squalene)

Locking out oxidation Whilst some companies use a diffusion process, ECiMa ™ uses a proprietary blending and consolidation process, chemically bonding the vitamin E to the polyethylene molecule at the start of the manufacturing process. This offers 2 distinct advantages:  allows uniform distribution of vitamin E across the cross section of the Absorbance (AU) polyethylene  minimises the vitamin E elution effect seen in infused vitamin E products 2 Not all vitamin E polyethylenes Time (minutes) are created equal High performance liquid chromatography chromagrams from non-polar solvent extraction 2. Data held on file.

Locking out oxidation The ‘Goldilocks Enigma’ Conventional doped vitamin E polyethylene use 1% wt, which can reduce cross-linking density and wear resistance of the polyethylene The ECiMa ™ grafting process allows low dosage of vitamin E to be used, 0.1% wt, optimising the cross-link density and wear resistance of the material, whilst minimising exposure to large amounts of vitamin E in the joint 3 3. Oral et al, 2008.

Locking out oxidation Oxidative shield The free radical stabilisation effect of vitamin E provides a natural barrier to potential long-term oxidation which can occur in vivo Test results show no evidence of oxidation following intensive ageing and cyclic loading in vitro where previous HXLPE liners have failed 2 2. Data held on file.

Next generation vitamin E HXLPE Ci C old Locking i rradiated out wear

Locking out wear Low wear – test data Designed to maximise survivorship, ECiMa ™ test results indicate ultra low wear rates 4 with the potential to reduce wear-related osteolysis in vivo , even with 40mm bearings  95% reduction compared to UHMWPE  83% reduction compared to HXLPE  reduction in wear compared to doped vitamin E HXLPE 5 4. Traynor et al, 2012. 5. Competitor literature

Next generation vitamin E HXLPE Ma M echanically Locking in a nnealed strength

Locking in strength What is mechanical annealing? Heat Heat deform Quench free radicals Below re-melt temperature (maintains mechanical integrity)

Locking in strength Test data: Superior mechanical properties 4 60 3% 50 40 34% 30 MPa UTS 20 10 0 ECiMa™ UHMWPE HXLPE 4. Traynor et al, 2012.

Locking in strength Mechanical integrity vs competitor products 5 5. Competitor literature

Locking in strength Test data: Environmental stress cracking  Cyclical loading 10MPa, 0.5Hz, to ASTM F671 1.5mc  Oxidation analysis  All ECiMa ™ samples completed 1.5mc  2 HXLPE failed  Oxidisation of HXLPE 4-5X greater than controls ECiMa ™ ECiMa ™ ECiMa ™ ECiMa ™ HXLPE HXLPE HXLPE HXLPE

Locking in life Locking out oxidation Locking out wear Locking in strength ECiMa ™ ECiMa ™ Improved wear resistance Oxidative stability (longevity) Vitamin E Mechanical integrity doped ECiMa ™ UHMWPE Vitamin E doped Vitamin E doped, Remelted, seq. Seq Seq annealed annealed annealed HXLPE HXLPE HXLPE Annealed HXLPE HXLPE UHMWPE UHMWPE

Locking in life Locking out oxidation E Blended Vitamin E provides an ‘oxidative shield’ actively stabilising the polyethylene insert from in vivo oxidation 4 Locking out wear Ci Cold irradiation allows cross-linking at the optimal radiation dose providing 95% reduction in wear compared with conventional polyethylene 4 Locking in strength M Mechanical annealing below the melt temperature provides a 45% increase in ultimate tensile strength compared to conventional HXLPE 4 a 4. Traynor et al, 2012.

References 1. Wang, 2009. 2. Data held on file, Corin Group PLC 3. Oral E, Godleski Beckos C, Malhi AS, Muratoglu OK. The effects of high dose irradiation on the cross-linking of vitamin E-blended ultra high molecular weight polyethylene. Biomaterials 2008:29;3557-60. Traynor A, Simpson D, Collins S. ECiMa ™ for low wear, optimal mechanical properties and oxidation resistance of hip bearings. Total 4. Hip Arthroplasty – Wear Behaviour of Different Articulations, EFORT Reference in Orthopaedics and Traumatology, Springer: ISBN 978-3-642-27360-5, 2012. 5. Competitor literature review.

Vitamin E Technology Locking in life