Metal levels in cemented total hip arthroplasty. A comparison of well-fixed and loose implants.
In a prospective study, synovial fluid metal levels from stainless steel, cobalt-chromium, and titanium-alloy cemented total hip implants were measured. There were 37 well-fixed and 44 loose hip arthroplasties. Tissue-metal levels were quantitated in the cases revised for loosening. Retrieval analysis for implant wear was performed. Synovial fluid analysis showed a fivefold increase in metal levels of loose compared with well-fixed stainless steel implants. There was a sevenfold increase in metal levels of loose compared with well-fixed cobalt-chromium implants. There was a 21-fold increase in metal levels of loose compared with well-fixed titanium-alloy (Ti-6Al-4V) implants. Tissue-metal levels from revised cobalt-chromium implants averaged 45 micrograms/g dry tissue weight compared to 4,470 micrograms/g dry tissue weight from revised titanium-alloy implants, a 100-fold increase. Implant retrieval analysis showed severe burnishing and scratching in all titanium-alloy femoral heads and extensive burnishing and scratching in the majority of the femoral stems. Well-fixed cemented implants have similar low synovial fluid metal levels. However, when loosening of implants occurs, titanium-alloy implants release disproportionate levels of metal into synovial fluid and local tissues compared to stainless steel or cobalt-chromium.
Brien
W W
WW
Department of Orthopaedic Surgery, University of Southern California, Los Angeles 90033-4608.
Salvati
E A
EA
Betts
F
F
Bullough
P
P
Wright
T
T
Rimnac
C
C
Buly
R
R
Garvin
K
K
D000497:Alloys; D002484:Cementation; D002857:Chromium / Q000032:analysis; D002858:Chromium Alloys; D003035:Cobalt / Q000032:analysis; D006622:Hip Prosthesis; D006801:Humans; D008670:Metals / Q000032:analysis*; D009532:Nickel / Q000032:analysis; D011446:Prospective Studies; D011475:Prosthesis Failure; D013193:Stainless Steel; D013582:Synovial Fluid / Q000737:chemistry*; D014025:Titanium / Q000032:analysis; D014639:Vanadium / Q000032:analysis
D000497:Alloys; D002858:Chromium Alloys; D008670:Metals; D014639:Vanadium; D002857:Chromium; D013193:Stainless Steel; C031462:titanium alloy (TiAl6V4); D003035:Cobalt; D009532:Nickel; D014025:Titanium