Effect of vancomycin-containing lubricant on vitamin E-stabilized UHMWPE wear in an in vitro total knee simulator: a pilot study

Abstract Topical vancomycin in primary total knee arthroplasty remains an investigational and controversial strategy because clinical evidence regarding infection prevention and wound complications is conflicting. This pilot study explored whether prolonged exposure to vancomycin-containing serum lubricant was associated with altered gravimetric wear of vitamin E-stabilized ultra-high-molecular-weight polyethylene (UHMWPE) tibial inserts. Eight identical bicondylar total knee arthroplasty systems were evaluated in two condition-specific four-station simulator runs: serum control and vancomycin-containing lubricant. In each run, three inserts underwent dynamic loading for 5.0 million cycles and one insert served as the shared load-soak control. For the exposed condition, 1 g of crystalline vancomycin was dissolved in 10 mL of distilled water and added to the serum lubricant to achieve a final lubricant volume of 300 mL, corresponding to a nominal vancomycin concentration of 3.33 mg/mL. The complete lubricant was renewed every 0.5 million cycles. Inserts were preconditioned in serum without vancomycin, and serial micro-CT handling was performed only in the vancomycin condition. The mean measured wear rate was 2.21 ± 0.92 mg/million cycles in the vancomycin-containing lubricant condition and 6.80 ± 3.07 mg/million cycles in the serum control condition, corresponding to a mean between-condition difference of − 4.59 mg/million cycles. All three wear-rate estimates for the serum control condition exceeded those obtained with vancomycin-containing lubricant. Because the two conditions were evaluated in separate simulator runs and differed in preconditioning and micro-CT handling, the observed between-condition difference cannot be attributed specifically to vancomycin. These findings should therefore be interpreted as preliminary descriptive evidence and do not permit conclusions regarding non-inferiority, clinical safety, or infection-prevention efficacy.