Effect of head surface roughness and sterilization on wear of UHMWPE acetabular cups.
The impact of femoral head surface roughness on wear of gamma-irradiation sterilized (3 MRad in nitrogen, crosslinked) and nonsterilized (not crosslinked) UHMWPE acetabular cups has been evaluated. Gravimetric wear testing was performed in a hip joint simulator for 2 x 10(6) cycles. CoCrMo heads were used with different surface roughness (R(a) = 15 nm and R(a) = 400 nm). The surface roughness after wear test was unchanged for the roughened heads, whereas the initially smooth heads showed a few scratches. The roughened heads increased the wear of the acetabular cups 2-fold. The gamma-irradiated cups tested against rough heads underwent the highest wear. The absorption of water was highest for the gamma-irradiated cups (0.0204% compared to 0.0031% after 85 days). Raman spectroscopy showed small but significant crystallinity changes in the wear zone, where the gamma-irradiated cups with the most extensive abrasion increased in crystallinity, whereas the nonsterilized cups underwent a crystallinity decrease.
Jedenmalm
A
A
Royal Institute of Technology (KTH), School of Chemical Science and Engineering, Fiber and Polymer Technology, SE-100 44 Stockholm, Sweden.
Affatato
S
S
Taddei
P
P
Leardini
W
W
Gedde
U W
UW
Fagnano
C
C
Viceconti
M
M
D000042:Absorption; D000077:Acetabulum; D005270:Femur Head; D005720:Gamma Rays; D006621:Hip Joint; D006801:Humans; D008422:Materials Testing / Q000379:methods; D011095:Polyethylenes / Q000592:standards*; D013242:Sterilization / Q000379:methods*; D013499:Surface Properties; D014800:Vitallium; D014867:Water
D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene; D014867:Water; D014800:Vitallium