Consequences of particles formation Increase in total surface area Local tissue response and release...
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Transcript of Consequences of particles formation Increase in total surface area Local tissue response and release...
Consequences of particles formation
Increase in total surface areaLocal tissue response and release of cytokines involved in bone resorption
Biological response
B.F. Morrey, Biological, Material, and Mechanical Considerations of Joint Replacement, 1993B.F. Morrey, Biological, Material, and Mechanical Considerations of Joint Replacement, 1993
Local tissue responseBiological response
Consequences of particles formation
Increase in total surface areaLocal tissue response and release of cytokines involved in bone resorptionSystemic effects
Biological response
Hip prosthesis implantedHip prosthesis implanted 2-year post-2-year post-opop
Systemic effect of metal particles– blood and urine
I. Milošev, P. Campbell, V. Pišot, J.Orhop. Res., 23 (2005) 526-535
Biological response
Consequences of particles formation
Increase in total surface areaLocal tissue response and release of cytokines involved in bone resorptionSystemic effects Transport of particles to distant organsPotential for carcinogenesis and hypersensitivity
Biological response
Metal sensitivity
Skin test for metal sensitivity are not correlative and are unable to predict delayed metal hypersensitivity !
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
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.
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 specialistDr. Maja Remškar, Jožef Stefan Institute
Thank you
www.ceramtec.comwww.wmt.com
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.
Primary hip and knee total hip replacements at the Valdoltra
Orthopaedic Hospital
676
942
67122 133 156 162 175
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351 412460
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925
1041
908913829
724686664673635649
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1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008
Knee prostheses Hip prostheses
Femoral head Femoral stem, Femoral stem Femoral head, Fracture plate femoral head acetabular inlay acetabular inlay
Stainlesssteel
Cobalt-base alloys
Titanium-base alloys
Ceramics
+priceavailability
Wear resistanceCorrosion resistanceFatique resistance
Corrosion resistance Elastic modulusFatique resistance Specific densityBiocompatibility
Wear resistanceCorrosion resistance Specific densityBiocompatibility
-Elastic modulusBiocompatibility
Elastic modulusBiocompatibility
Elastic modulusBiocompatibility
Elastic modulusFracture
Origin of wear debris and their transport in the bodyA – Cemented prostheses; B – Uncemented prostheses
H.-G. Willert, et al., “Biological, Material and Mechanical Considerations of Joint Replacement”, 1993
Wear debris
wear debris particles
Bone cement particles
origin: femoral stem acetabular cup
Wear debris
Cortical boneCancellous bone
Bone cementPolyethylene
Metal
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
Wear debris
Hip prosthesis explantedHip prosthesis explanted 2-year post-2-year post-opop
Systemic effect of metal particles– blood and urine
I. Milošev, P. Campbell, V. Pišot, J.Orhop. Res., 23 (2005) 526-535
Biological response
days post-op
0 100 200 300 400 500 600 700 800
Ser
um C
o (u
g/L)
0,0
0,1
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control group
0 200 400 600 8000,0
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Ca-P-O-particle
Different composition of particles arises from the formation of solid lubricating layer at the surface containing denatured proteins and metal oxides.
I. Milošev, M. Remškar, J. Biomed. Mater. Res., in press