Abstract
Introduction
The utility of vancomycin powder application into the surgical site has recently shown efficacy in decreasing infections in patients undergoing thoracolumbar spine surgery. The effect on polyethylene wear after intraoperative placement of vancomycin powder at the surgical site of total joint replacements has not been determined. The purpose of this study is to compare wear behavior of material couples of Cobalt Chromium Alloy (CoCr) on ultra high molecular weight polyethylene (UHMWPE) to identical wear couples with vancomycin powder added prior to the start of wear simulation.
Methods
A custom-designed six-station wear simulator was used to establish in vitrowear characteristics of CoCr on UHMWPE on test articles fabricated from materials identical to total knee implants. Three stations included vancomycin powder added to the 36% bovine calf serum solution used in each station. Cyclic articulation simulations were run for 10 million cycles (Mc) at 4 ± 0.3 Hz under a constant axial load of 89N over 25 degrees of flexion-extension. UHMWPE wear was measured using photography, stereomicroscopic examination, and gravimetric measurements at the end of 0.5, 1, 2.5, 5, and 10 Mc.
Results
After photographic and stereomicrographic examination, no significant differences between the UHMWPE wear mark length, width, and area of the vancomycin group and the control group were found at any of the time points. There was no gravimetrically detectable difference in the amount of wear between the two groups. The vancomycin test group lost an average of 0.13 ± 0.07 after 2.5 MC and similarly the control test group lost an average of 0.13 ± 0.15 mg (p = 0.95).
Discussion
The addition of vancomycin powder to CoCr on UHMWPE wear simulator demonstrated no detrimental effects on the prostheses in vitro. Topical vancomycin powder may have a role in infection prevention after total joint arthroplasty. A well designed clinical study is needed to further elucidate this role.
