Iatrogenic surface damage during femoral component impaction in total knee arthroplasty

Application of prosthesis components during knee arthroplasty surgery involves impacting the femoral component using an impaction device and a heavy mallet. This could damage the component and may therefore be of concern to knee surgeons. Using a drop tower with a set-up that mimics the impaction generated clinically when a surgeon hits the femoral component, we investigated the possible surface damage to the femoral component. Three parameters were obtained and compared with a contact profilometer to characterize the roughness: Ra, Rpk and Rz. The effect of the impacts on the contour of the femoral components was also investigated. After 3 series of impactions, no difference in surface roughness of the femoral component important enough to increase the wear rate could be detected neither for Cobalt Chrome or Oxidized Zirconium components. Our study therefore indicates that impacting the femoral component during TKA does not alter the component's surface roughness.