Orthopaedic implant components as a source of

nanoparticlesIngrid Milošev

Jožef Stefan Institute, Ljubljana, andJožef Stefan Institute, Ljubljana, andValdoltra Orthopaedic Hospital, Ankaran, SloveniaValdoltra Orthopaedic Hospital, Ankaran, Slovenia

Conference on Nano-Safety, Conference on Nano-Safety, Ljubljana, 22-24 April 2009Ljubljana, 22-24 April 2009

Number of implants and devices for USA (global numbers 2-3 times higher)

Type of implant Number

Intraocular implants

Intraocular lenses 2.500.000

Contact lenses 30.000.000

Cardiovascular implants

Pace makers 400.000

Vascular grafts 300.000

Stents 1.500.000

Heart valves 100.000

Orthopaedic implants

Total hip replacements

250.000

Total knee replacements

250.000

Dental implants 910.000

Biomaterial Science, B.D. Ratner, A.S. Hoffman, F.J. Schoen, J.E. Lemons, 2004Biomaterial Science, B.D. Ratner, A.S. Hoffman, F.J. Schoen, J.E. Lemons, 2004

Indications for total hip replacement: - osteoarthritis- osteoarthritis secondary to dysplasia- aseptic femoral head necrosis- rheumatoid arthritis- post-traumatic arthritis

Radigraph image of THR: (A) Post implantation (B) Prior revision surgery – aseptic loosening with

osteolytic zones along the stem and changed cup position

Animation: http://www.wmt.com/

Survivorship curve is a long-term indicator of the successfulness

of a particular prosthesis.

Data are created based in the Valdoltra

Register of hip and knee prostheses.

fu12,5010,007,505,002,500,00

Cum

Sur

viva

l

1,00

0,95

0,90

0,85

0,80

MP-censoredMM-censoredMPMM

proteza

Time in situ / yearsTime in situ / years

Cu

mu

lati

ve s

urv

ivors

hip

Cu

mu

lati

ve s

urv

ivors

hip

At 12 years post-op, 90% At 12 years post-op, 90% of prostheses still of prostheses still

implantedimplanted

826 hip revision operations in the period from 2002 to 2007

585

183

258

144

6748

30 26 23 8 19 20

0

100

200

300

400

500

600

700

Loosening Looseningof acetab.

part

Looseningof femoral

part

Looseningof bothparts

Deepinfection

Fracture ofthe femur

Dislocation Two-stagerevision

Osteolysisof femoral

part

Pain Fracture ofthe

prosthesis

Other

Reason for revision

Num

ber

of r

evis

ions

71%

Aseptic loosening related to the formation of wear debris and consequent osteolysis is reason for revision in >70%.

Origin of wearSurface wear damageWear particles

Polyethylene particles Metal particlesCement particles

Novel bearing combinationsMetal-on-metalCeramic-on-ceramic

Biological consideration of particulate debris

Introduction

Polyethylene particles

origin: acetabular cup,acetabular inlay

Wear debris

e f

Mode 1: two primary bearing surfaces (a,b)

Mode 2: primary surface moving against a

secondary surface (c, d)

Mode 3: primary surfaces including third particles

interposed (e, f)

d

ba

c

e f

Metal particlesFor SEM analysis – filtrate the bottom layer through 0.2 um polycarbonate filter paper and coat with gold

Polyethylene particles• For SEM analysis - filtrate the top layer through 0.2 um polycarbonate filter paper and coat with gold

Isolation procedureby NaOH digestion