cadera / hip - Active Congress.......

MARTES / TUESDAY
44
tional/control polyethlene 57,112,132 . Some,
however, report increased wear in highly
cross-linked polyethylene when articulated
against roughened femoral heads. 56
• In Vivo/ Clinical Data
• Highly Cross-linked, Thermally Stabilized
Polyethylene
• Clinical data scant (Martell et al.) 87
- Minimum 2 year follow-up of 39 crosslinked
(gamma XRT in N 2 ), thermally stabilized
(annealed) polyethylene inserts
- Linear wear (in vivo) 0.14mm/yr
- Volumetric wear (in vivo) 0.54mm 3 /yr
- Both linear and volumetric wear rates
were signifi cantly less compared to control
conventional polyethylene
• Highly Cross-linked Polyethylene without
Thermal Treatment
• Oonishi et al. 158
- Cross-linked with 100 Mrads of Gamma
radiation in air
- Cobalt-Chrome femoral heads
- Long-term wear rates
• 290um/year for non cross-linked (higher
than historically reported)
• 60um/year for cross-linked
• 79% reduction in wear
• Wroblewski et al. 214
- Chemically cross-linked with saline
process
- Ceramic (Alumina) Femoral Heads
- 19 patients with up to 8.3 yr. follow-up
• Extremely low wear (0.22mm/year)
• Question if wear rate secondary to ceramic
femoral head or highly cross-linked
polyethylene
• Grobbelaar et al. 75
- Cross-linked with 10 Mrads Gamma radiation
immersed in acetylene gas
- 30mm Chrome Cobalt Heads
- 14-21 yr follow-up
• “Lack of measurable wear”
D. Potential Advantages of Highly Crosslinked
Polyethylene
57,75,112,132-134, 146,147,158,209,214
• Decreased wear