Orthopedic biomaterials

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Orthopedic biomaterials

  1. 1. Orthopedic biomaterials snehal menon Sinhgad college of engineering, pune
  2. 2. Biomaterials Biomaterials orthopedics for
  3. 3. Biomaterials classification
  4. 4. First generation  When synthetic materials were first used in biomedical applications, the only requirement was to ‘achieve a suitable combination of physical properties to match those of the replaced tissue with a minimal toxic response of the host’ (Hench 1980).  They were the ‘first-generation biomaterials’, according to Hench's classification, because they were ‘inert’ so as to reduce the immune response and the foreign body reaction to a minimum.
  5. 5. Second generation  The second generation of biomaterials should be considered to have appeared between 1980 and 2000, and was defined by the development of bioactive materials' ablility to interact with the biological environment to enhance the biological response and the tissue/surface bonding, as well as by the development of bioabsorbable materials' ability to undergo a progressive degradation while new tissue regenerates and heals
  6. 6. Third generation  The third-generation biomaterials are meant to be new materials that are able to stimulate specific cellular responses at the molecular level (Hench & Polak 2002)  These materials' properties should merge with their ability to signal and stimulate specific cellular activity and behaviour  The third generation of biomaterials appeared approximately at the same time as scaffolds for tissue engineering applications started to be developed
  7. 7. Biomaterials in orthopedic surgery  Metallic materials  stainless century)  Ti steel and cobalt–chrome-based alloys (early twentieth and Ti alloys (introduced by the 1940s)  NiTi  The shape memory alloys (1960s) first really successful substitutive joint prosthesis was the total hip prosthesis developed by Charnley in the very late 1950s (Charnley 1960) This was a cemented prosthesis with a stem made of stainless steel.
  8. 8. Hip alloprosthesis (a) Massive proximal femur replacement allograft and patient’s femur. (b) Femoral stem component in place.
  9. 9. Bone plate, introduced in the early 1900s to assist in the healing of skeletal fractures, were among the earliest successful biomedical implants Artificial knee joints are implanted in patients with a diseased joint to alleviate pain and restore function
  10. 10.  Ceramic materials • alumina, zirconia and several porous ceramics • These non-metallic inorganic materials have a limited range of formulations • The microstructure is highly dependent on the applied manufacturing process (maximum temperature, duration of the thermal steps, purity of the powder, size and distribution of the grains and porosity) • It has a clear and direct effect on both the mechanical and biological properties.
  11. 11.  Polymers  silicone rubber, PE, acrylic resins, polyurethanes, polypropylene (PP) and polymethylmethacrylate (PMMA)  polyglycolide (PGA), polylactide (PLA), polydioxanone (PDS), poly(ϵ-caprolactone) (PCL), polyhydroxybutyrate (PHB), polyorthoester, chitosan, poly(2-hydroxyethylmethacrylate) (PHEMA), hyaluronic acid and other hydrogels
  12. 12. Case studies
  13. 13. TOTAL KNEE REPLACEMENT  History • Most hip and knee prosthesis are made of cobalt chrome alloy or of titanium • The polyethylene stainless steel joints fixed to bone with polymethlmethacrylate (PMMA) plastic, often called "bone cement”, is used still widely in the knee with newer techniques to reduce its failure rate • These include mixing under vacuum to prevent air bubbles in the plastic.
  14. 14.  Types • Total condylar knee prosthesis appeared in the 1980s with cobalt-chrome alloy femoral component and high density polyethylene tibial component • The successful designs use the ligaments of the knee to hold the knee in place and merely resurface the arthritic joint
  15. 15. Total condylar knee prosthesis
  16. 16. The surgery Surgical picture of a total knee before wound closure
  17. 17.  Oxidized zirconium • Eleven years in development, the Oxidized Zirconium knee is considered an industry-defining technology • Oxidized Zirconium components are made of a metallic zirconium alloy that is heated to convert the surface to a ceramic (zirconia), the best of both worlds can be achieved • Compared to cobalt chrome, Oxidized Zirconium, in wear simulation testing, reduced the rate of polyethylene wear by 85 percent
  18. 18.  Wear Simulation Comparison of a Zirconia and a Cobalt Chrome Femoral knee Implant • In recent years the major cause of long-term failure of hip and knee total arthroplasties has been identified as originating with wear particles produced at the interface in the synthetic articulating surfaces • Researchers have tested the hypothesis that a zirconia (zirconium oxide) femur would produce less wear of the counterfacing ultra-high molecular weight polyethylene (UHMWPE) insert than a standard cobalt chrome molybdenum femur of similar design • The reduction was due to the increased hardness, scratch resistance and smoothness of the zirconia femurs
  19. 19. THE END

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