Consequences of particles formation

1
Consequences of particles formation
Biological response

• 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
Consequences of particles formation
Biological response

• 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 and
urine
Hip prosthesis implanted
2-year post-op
I. Miloev, P. Campbell, V. Piot, J.Orhop. Res.,
23 (2005) 526-535
5
Consequences of particles formation
Biological response

• 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. Piot, R. Trebe, S. Kovac)
• Vesna Levaic, MD, Arthroplasty register
• Prof. Andrej Coer, University of Primorska,
  pathology specialist
• Dr. Maja Remkar, Joef Stefan Institute

Thank you
10
Ceramic particles origin femoral
headacetabular inlay
Wear debris
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.ceramtec.com
www.wmt.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
Bone cement particles origin femoral stem
acetabular cup
Wear debris
17
Ceramic wear particles
Wear debris
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 and
urine
Hip prosthesis explanted
2-year post-op
I. Miloev, P. Campbell, V. Piot, J.Orhop. Res.,
23 (2005) 526-535
20
Cr-O-particle
Ti-particle
21
I. Miloev, M. Remkar, 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