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

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

Ceramic particles

origin:

femoral headacetabular inlay

Wear debris

www.endoplus.comwww.endoplus.com

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

231

351 412460

587

925

1041

908913829

724686664673635649

0

200

400

600

800

1000

1200

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

Diffusely distributed lymphocytic infiltrates

Perivascular lymphocytic

infiltrates

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

Ceramic wear particles

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

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

0,2

0,3

0,4

0,5

0,6

0,7

0,8

control group

0 200 400 600 8000,0

0,2

0,4

0,6

0,8

Cr-O-particle Ti-particle

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

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

a

c

b

a

c

b