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Consequences of particles formation

Biological response. Consequences of particles formation. Increase in total surface area Local tissue response and release of cytokines involved in bone resorption. Biological response. Local tissue response.

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Consequences of particles formation

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  1. Biological response Consequences of particles formation • Increase in total surface area • Local tissue response and release of cytokines involved in bone resorption

  2. Biological response Local tissue response B.F. Morrey, Biological, Material, and Mechanical Considerations of Joint Replacement, 1993

  3. Biological response Consequences of particles formation • Increase in total surface area • Local tissue response and release of cytokines involved in bone resorption • Systemic effects

  4. Biological response Systemic effect of metal particles– blood andurine Hip prosthesis implanted 2-year post-op I. Milošev, P. Campbell, V. Pišot, J.Orhop. Res., 23 (2005) 526-535

  5. Biological response Consequences of particles formation • Increase in total surface area • Local tissue response and release of cytokines involved in bone resorption • Systemic effects • Transport of particles to distant organs • Potential for carcinogenesis and hypersensitivity

  6. Metal sensitivity Skin test for metal sensitivity are not correlative and are unable to predict delayed metal hypersensitivity !

  7. Willert HG et al., Osteologie (2000), World Tribology Forum in Artroplasty (2001) Delayed Type Hypersensitivity (DTH) related to the use of metal-on-metal prostheses: • Diffuse and perivascularly oriented lymphocyte infiltration • Macrophages (sometimes with drop-like inclusions) • Plasma cells* • Infiltrates of B-lymphocytes* • Massive fibrin exudations* • Clinical status: pain

  8. Concluding remarks • Benefits of total joint replacements are most important fot the patient. • We should be aware, however, that loosened implant components are a source of various types of nanoparticles – metal, polyethylene, PMMA and ceramic. • Knowledge on their morphology and composition contributes to the understanding of failure mechanism. • Efforts are directed to the prolongation of life-time of implants by increasing their wear resistance. • Joint collaboration studies between medical and research community are necessary.

  9. Acknowledgments • Orhopaedic surgeons at the Valdoltra Orthopaedic Hospital (V. Pišot, R. Trebše, S. Kovač) • Vesna Levašič, MD, Arthroplasty register • Prof. Andrej Coer, University of Primorska, pathology specialist • Dr. Maja Remškar, Jožef Stefan Institute Thank you

  10. Wear debris Ceramic particles origin: femoral headacetabular inlay www.endoplus.com

  11. Novel bearing combinations Lower wear implies a lower number of wear debris particles and, consequently, a decreased incidence of aseptic loosening. However, other problems may arise. www.wmt.com www.ceramtec.com

  12. Primary hip and knee total hip replacements at the Valdoltra Orthopaedic Hospital

  13. Femoral head Femoral stem, Femoral stem Femoral head, Fracture plate femoral head acetabular inlay acetabular inlay

  14. Diffusely distributed lymphocytic infiltrates Perivascular lymphocytic infiltrates

  15. Wear debris wear debris particles Origin of wear debris and their transport in the body A – Cemented prostheses; B – Uncemented prostheses H.-G. Willert, et al., “Biological, Material and Mechanical Considerations of Joint Replacement”, 1993

  16. Wear debris Cortical bone Cancellous bone Bone cement Polyethylene Metal Bone cement particles origin: femoral stem acetabular cup

  17. Wear debris Ceramic wear particles

  18. Wear debris Procedure for isolation of metal and polyethylene particles from periprosthetic tissue using hydroxide digestion • Digest minced tissue in 5M NaOH at 65oC • Ultrasonicate for 10 minutes • Centrifugate at 6000 rpm for 1h • Top layer contains polyethylene particles • Bottom layer contains metal particles • Hydrolyse at 80oC for 1h • Ultrasonicate for 5 minutes • Add 3 ml of isopropanol • Centrifugate at 6000 rpm for 1 h

  19. Biological response Systemic effect of metal particles– blood andurine Hip prosthesis explanted 2-year post-op I. Milošev, P. Campbell, V. Pišot, J.Orhop. Res., 23 (2005) 526-535

  20. Cr-O-particle Ti-particle

  21. I. Milošev, M. Remškar, J. Biomed. Mater. Res., in press Different composition of particles arises from the formation of solid lubricating layer at the surface containing denatured proteins and metal oxides. Ca-P-O-particle

  22. a Different composition of particles arises from the formation of solid lubricating layer at the surface containing denatured proteins and metal oxides. b c b c a

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