METALS FOR TJA PAST PRESENT AND FUTURE 1900-19401940-196019701980199020002010 Stainless steel Cobalt-Chromium Alloy Titanium Oxinium Selection criteria 1--Inertness/Biocompatibility Strength Lower modulus I Scratch-resist. Lubrication Non-Allergen
METALS FOR TJA: METALS FOR TJA: PAST, PRESENT, AND FUTURE PAST, PRESENT, AND FUTURE 1900 -1940 1940 -1960 1970 1980 1990 2000 2010 Stainless Steel Stainless Steel Cobalt -Chromium Alloy Chromium Alloy Titanium Titanium Oxinium Oxinium Selection Criteria Selection Criteria Inertness/Biocompatibility Inertness/Biocompatibility Strength Strength Lower Modulus Lower Modulus Scratch Scratch -resist. resist. Lubricatious Lubricatious Non -Allergen. Allergen
ORTHOPAEDIC METALS ADVANTAGES DISADVANTAGES Stainless Strength Potential for corrosion Steel Ease of manuf. High mod of elasticity Availability Cobalt- Strength High mod, of elasticity Chromium Rel. wear resist Titanium Strength Poor wear resistance Low modulus Corrosion resist Oxinium Scratch-resist Low modulus
ORTHOPAEDIC METALS ORTHOPAEDIC METALS ADVANTAGES ADVANTAGES DISADVANTAGES DISADVANTAGES Stainless Stainless Strength Strength Potential for corrosion Potential for corrosion Steel Ease of Ease of manuf. High mod. of elasticity High mod. of elasticity Availability Availability Cobalt - Strength Strength High mod. of elasticity High mod. of elasticity Chromium Chromium Rel. wear resist. . wear resist. Titanium Titanium Strength Strength Poor wear resistance Poor wear resistance Low modulus Low modulus Corrosion resist. Corrosion resist. Oxinium Oxinium Scratch Scratch -resist. resist. ? Low modulus Low modulus
Composition of Orthopaedic metals cr(27·30% N(10-17%) Mo(2-4% c(0.03% N(25%) Mn. P S, Si, (-2.8% total) Fe, C, Mn, Si Fe Co (-3 Stainless steel Cobalt Alloy (316L) A(5.5·6.5% (F75) V354%0) Nb(25%) Fe, C, O(-046% total) Ti Titanium Oxinium Ti·6A|-4V) ASTM B550
Oxinium ASTM B550 ASTM B550 Zr Nb (2.5%) Composition of Orthopaedic Metals Composition of Orthopaedic Metals
How is the ceramic surface produced on Oxinium?: Oxidation process Wrought zirconium alloy device is heated in air Metal transforms as oxide grows; not a coating Zirconium Oxide zirconia ceramic)is 5 um thick. Oxygen Diffusion Zirconium metal alloy is heated in air Original Surface Oxygen diffuses into the metal surface Ceramic Oxide Surface becomes enriched in oxygen Oxygen Enriched Metal Surface transforms to ceramic oxide Metal substrate G. Hunter. s&n
Metal Substrate How is the Ceramic Surface Produced on Oxinium?: Oxidation Process • Wrought zirconium alloy device is heated in air. • Metal transforms as oxide grows; not a coating. • Zirconium Oxide (Zirconia ceramic) is ~5 µm thick. Oxygen Enriched Metal Original Surface Air Oxygen 500oC Diffusion Ceramic Oxide Oxygen Enriched Metal Zirconium metal alloy is heated in air Oxygen diffuses into the metal surface Surface becomes enriched in oxygen Surface transforms to ceramic oxide G. Hunter, S&N
Co-Cr allOY VERSUS Zr-Nb alloy THICKNESS OF THE OXIDE Chromium oxide 0.01um Co-Cr alloy 500 times thicker Ceramic Zirconium oxide m Oxinium Zr-Nb alloy Metal
Co-Cr ALLOY VERSUS Cr ALLOY VERSUS Zr-Nb ALLOY: Nb ALLOY: THICKNESS OF THE OXIDE THICKNESS OF THE OXIDE Co-Cr alloy Cr alloy Chromium oxide 0.01 µm 500 times thicker 500 times thicker Zr-Nb alloy Nb alloy Zirconium oxide 5 µm Ceramic Metal Oxinium