Antimicrobial agents and low-molecular weight polypeptides affect polyethylene wear in knee simulator testing

• Knee simulator wear tests were performed with six different lubricants.
• The effects of antimicrobial agents on wear were investigated.
• Low-molecular weight polypeptide concentrations were measured.
• Sodium azide and an antibiotic–antimycotic mixture were ineffective.
• A predator bacterium indicated potential use for implant wear testing.

A series of eight wear tests with six different calf serum lubricants were performed on a displacement-controlled knee simulator. The calf serum lubricants varied in constituent fractions, dilutive media, and antimicrobial agent. The difference in low-molecular weight polypeptide concentration was determined in all calf serum lubricants and this allowed exploration of its role in the PE wear process. Sodium azide was not an effective antimicrobial agent. The subsequently used antibiotic–antimycotic mixture was initially effective in eliminating bacterial growth but its efficacy became exhausted as the testing period progressed. In the present pilot study, a predator bacterium Bdellovibrio bacteriovorus was shown to prey on the antibiotic resistant bacterium, suggesting its potential use in knee simulator wear testing.