Premium
Polyethylene cross‐linking by two different methods reduces acetabular liner wear in a hip joint wear simulator
Author(s) -
D'Lima Darryl D.,
Hermida Juan C.,
Chen Peter C.,
Colwell Clifford W.
Publication year - 2003
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1016/s0736-0266(02)00240-1
Subject(s) - polyethylene , cross linked polyethylene , materials science , composite material , irradiation , ultra high molecular weight polyethylene , gravimetric analysis , chemistry , nuclear physics , physics , organic chemistry
Advances in cross‐linking have led to the development of wear resistant ultrahigh molecular weight polyethylene for total joint replacement. This study compared wear reduction by two different cross‐linking methods as measured in a hip wear simulator. One highly cross‐linked polyethylene was treated with 7.5 Mrad gamma irradiation with post‐irradiation annealing and a sterilization dose of 2.5 Mrad (10 Gamma), while the other used 9.5 Mrad warm irradiation with 10 MeV electron‐beam (9.5 EB). Liners of the same design, made from nominally cross‐linked (gamma sterilized) polyethylene were also tested. Gravimetric wear analysis was performed every 500,000 cycles for 5,000,000 cycles. After correcting for weight gain due to water absorption, the nominally cross‐linked liners demonstrated mean wear rates of 15.7 (±1.7) and 12.5 (±1.0) mg/million cycles. Both highly cross‐linked polyethylene liners demonstrated significantly less wear than their respective controls (with mean wear rates of 1.5 (±1.2) and –1.4 (±1.5) mg/million cycles). The 9.5 EB liners gained weight presumably due to increased fluid absorption, in addition to that measured in loaded–soaked control implants. Any wear occurring was therefore assumed to have been more than offset by weight gain. Highly cross‐linked polyethylene was significantly more wear resistant than non‐ or nominally cross‐linked polyethylene. The differences in wear rates between the two highly cross‐linked polyethylene designs (9.5 EB or 10 Gamma) are probably too small to be clinically significant. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.