Orthopaedic bone cement: do we know what we are using?
Bone cements produced by different manufacturers vary in their mechanical properties and antibiotic elution characteristics. Small changes in the formulation of a bone cement, which may not be apparent to surgeons, can also affect these properties. The supplier of Palacos bone cement with added gentamicin changed in 2005. We carried out a study to examine the mechanical characteristics and antibiotic elution of Schering-Plough Palacos, Heraeus Palacos and Depuy CMW Smartset bone cements. Both Heraeus Palacos and Smartset bone cements performed significantly better than Schering-Plough Palacos in terms of mechanical characteristics, with and without additional vancomycin (p < 0.001). All cements show a deterioration in flexural strength with increasing addition of vancomycin, albeit staying above ISO minimum levels. Both Heraeus Palacos and Smartset elute significantly more gentamicin cumulatively than Schering-Plough Palacos. Smartset elutes significantly more vancomycin cumulatively than Heraeus Palacos. The improved antibiotic elution characteristics of Smartset and Heraeus Palacos are not associated with a deterioration in mechanical properties. Although marketed as the 'original' Palacos, Heraeus Palacos has significantly altered mechanical and antibiotic elution characteristics compared with the most commonly-used previous version.
Bridgens
J
J
Northern General Hospital, Herries Road, Sheffield S5 7AU, UK. jpbridgens@doctors.org.uk
Davies
S
S
Tilley
L
L
Norman
P
P
Stockley
I
I
D000900:Anti-Bacterial Agents / Q000032:analysis*; D019643:Arthroplasty, Replacement; D001843:Bone Cements / Q000032:analysis*; D005839:Gentamicins / Q000032:analysis; D006245:Hardness Tests; D006801:Humans; D008422:Materials Testing; D019904:Polymethyl Methacrylate / Q000032:analysis*; D013223:Statistics as Topic; D013314:Stress, Mechanical; D014640:Vancomycin / Q000032:analysis; D016474:Weight-Bearing / Q000502:physiology*
D000900:Anti-Bacterial Agents; D001843:Bone Cements; D005839:Gentamicins; D014640:Vancomycin; D019904:Polymethyl Methacrylate