Polyethylene Damage Mechanisms
in Total Hip & Total knee Surgeries
Dr.Sandeep Agrawal,
Bone Joint Surgeon,
Agrasen Hos...
Polyethylene Damage Mechanisms
 Delamination
 Adhesive/Abrasive
2
Wear
 Pitting
 Creep
 Cold Flow
Delamination
Delamination
 Delamination occurs due to initiation
and propagation of subsurface cracks
and can result in the removal...
Crack
 Tibial insert subjected to compressive stresses immediately
under the contact area, with a peak stress at a dept...
Delamination
 Primary cause of most polyethylene-related
total knee failures
 result in loss of geometric conformity ...
WEAR :
motion between surfaces  loss of
material from the surfaces of the prosthesis
plastic deformation
CREEP  impl...
Wear
8
Adhesive wear
Abrasive wear
Transfer wear
Fatigue wear
Third body wear
Adhesive/Abrasive Wear
contributes to implant failure mainly by
generating particulate debris that
results in periprost...
Abrasive wear
Generation of wear debris from the
cutting and removal of the soft
polyethylene articular surface by hard...
Adhesive Wear
 Adhesive wear causes removal of
small particles of wear debris, usually
a few micrometers or smaller in...
Adhesive Wear
 M-G I PE s/p 10y/o
 Lace or ripple ,are
the likely
precursors to
adhesive/abrasive
wear
lace rippl...
Adhesive Wear
 Occurs at primary articulations, i.e.,
the tibiofemoral and patellofemoral
articulations, and at backsi...
Pitting
 Pitting is another fatigue-related
phenomenon
 results from the coalescence
of shallow subsurface cracks
o...
Creep
 Permanent deformation resulting from
prolonged application of a stress
below the elastic limit
Creep
 Deformation that occurs over period of time
when a material is subjected to constant
stress at constant tempera...
Cold flow
 Permanent deformation of plastics
remaining after load applied at
temperature below distortion
temperature...
Cold flow
 The distortion, deformation, or
dimensional change which takes
place in materials under continuous
load at...
Polyethylene Damage Mechanisms
 extent of oxidative embrittlement of the
polyethylene resulting from gamma
sterilizati...
method of sterilization of
polyethylene components
 gamma irradiation in air 55% Delamination
reaction of oxygen with ...
resin type and the consolidation
method affect the delamination
resistance
 Himont 1900 polyethylene resin in
combina...
Application of crosslinking technology
in total knee replacement
 high-dose radiation used to achieve a
high crosslink...
Application of crosslinking technology
in total knee replacement
 The preliminary in vitro knee simulator
testing of h...
of 23

Polyethylene Damage Mechanisms in Total Hip & Total knee Surgeries ,DR.SANDEEP AGRAWAL Agrasen Fracture Hospital Gondia Maharashtra

Polyethylene Damage Mechanisms in Total Hip & Total knee Surgeries ,DR.SANDEEP AGRAWAL Agrasen Fracture Hospital Gondia Maharashtra Cause for Failure or Revision for Joint Replacement surgeries THR , TKR Hip Knee Pain Instability
Published on: Mar 4, 2016
Published in: Health & Medicine      
Source: www.slideshare.net


Transcripts - Polyethylene Damage Mechanisms in Total Hip & Total knee Surgeries ,DR.SANDEEP AGRAWAL Agrasen Fracture Hospital Gondia Maharashtra

  • 1. Polyethylene Damage Mechanisms in Total Hip & Total knee Surgeries Dr.Sandeep Agrawal, Bone Joint Surgeon, Agrasen Hospital, Gondia Maharashtra India drsandeep123@gmail.com 09960122234
  • 2. Polyethylene Damage Mechanisms  Delamination  Adhesive/Abrasive 2 Wear  Pitting  Creep  Cold Flow
  • 3. Delamination
  • 4. Delamination  Delamination occurs due to initiation and propagation of subsurface cracks and can result in the removal of large (>0.5-mm) flakes of polyethylene wear debris.  Crack initiation and propagation occur when materials fatigue following repetitive stresses.
  • 5. Crack  Tibial insert subjected to compressive stresses immediately under the contact area, with a peak stress at a depth of 1 to 2 mm below the surface  Stresses outside the contact area are reversed and are tensile in nature.  As a result, during the rolling-sliding motion of the femoral component, subsurface region of polyethylene is subjected to completely reversing cycles of stress, i.e., compression and tension.  This fluctuating stress environment is precursor to fatigue, leading to the initiation and propagation of cracks in the material.
  • 6. Delamination  Primary cause of most polyethylene-related total knee failures  result in loss of geometric conformity  alter pattern of load distribution  eventually result in accelerated implant failure by disengagement or fracture of tibial insert or wear-through .
  • 7. WEAR : motion between surfaces  loss of material from the surfaces of the prosthesis plastic deformation CREEP  implant shape change, not causing loss of material or producing particulate debris 7
  • 8. Wear 8 Adhesive wear Abrasive wear Transfer wear Fatigue wear Third body wear
  • 9. Adhesive/Abrasive Wear contributes to implant failure mainly by generating particulate debris that results in periprosthetic osteolysis
  • 10. Abrasive wear Generation of wear debris from the cutting and removal of the soft polyethylene articular surface by hard asperities on the femoral component By hard third-body particles, such as bone chips or bone-cement particles
  • 11. Adhesive Wear  Adhesive wear causes removal of small particles of wear debris, usually a few micrometers or smaller in size  It is initiated by orientation and strain hardening of the implant surface
  • 12. Adhesive Wear  M-G I PE s/p 10y/o  Lace or ripple ,are the likely precursors to adhesive/abrasive wear lace ripple
  • 13. Adhesive Wear  Occurs at primary articulations, i.e., the tibiofemoral and patellofemoral articulations, and at backside,and tibial post-cam articulation of posterior stabilized total knee designs
  • 14. Pitting  Pitting is another fatigue-related phenomenon  results from the coalescence of shallow subsurface cracks or cracks initiated on the surface  occurs mostly on the articular surfaces, does not result in a substantial loss of material.
  • 15. Creep  Permanent deformation resulting from prolonged application of a stress below the elastic limit
  • 16. Creep  Deformation that occurs over period of time when a material is subjected to constant stress at constant temperature  In metals, creep usually occurs only at elevated temperatures.  Creep at room temperature is more common in plastic materials and is called cold flow or deformation under load.
  • 17. Cold flow  Permanent deformation of plastics remaining after load applied at temperature below distortion temperature is removed.  It is an alternate term for creep in plastics (ASTM D-674) and rubber (ASTM D-530).
  • 18. Cold flow  The distortion, deformation, or dimensional change which takes place in materials under continuous load at temperatures within the working range (cold flow is not due to heat softening).
  • 19. Polyethylene Damage Mechanisms  extent of oxidative embrittlement of the polyethylene resulting from gamma sterilization in air  stress state of the components implant design PS designs generally have more conforming articulating surfaces than CR type, lower stress levels polyethylene thickness thicker inserts provide more cushioning and lower stresses in the polyethylene than do thinner ones soft-tissue stability component alignment
  • 20. method of sterilization of polyethylene components  gamma irradiation in air 55% Delamination reaction of oxygen with the residual free radicals that are generated by gamma irradiation, leads to the degradation of the mechanical properties of polyethylene. embrittlement  ethylene oxide gas 0% Delamination
  • 21. resin type and the consolidation method affect the delamination resistance  Himont 1900 polyethylene resin in combination with direct compression-molding has been shown to have superior resistance to delamination  ram-extruded GUR 4150 resin
  • 22. Application of crosslinking technology in total knee replacement  high-dose radiation used to achieve a high crosslink density  followed by melting to eliminate the residual free radicals  substantially increases the delamination resistance of polyethylene after accelerated aging
  • 23. Application of crosslinking technology in total knee replacement  The preliminary in vitro knee simulator testing of highly crosslinked polyethylenes suggests that these polyethylenes reduce adhesive/abrasive wear and eliminate delamination  Two types of highly crosslinked polyethylene tibial inserts have been in clinical use for more than one year, and there have been no reports of early in vivo complications.

Related Documents