Surface Damage of Patellar Components Used in Total Knee Arthroplasty
BACKGROUND:Patellofemoral complications are a common cause of failure of total knee replacement. In this study, we examined eighty-five patellar components that had been retrieved for a variety of reasons after a mean of 71.9 months in vivo. The objective of this study was to identify factors contributing to surface damage of patellar components in total knee replacements.
METHODS: The retrieved patellar components were of three primary designs: dome-shaped, sombrero-shaped, and pseudo-anatomic. Five zones on each specimen were evaluated for five different types of damage (creep, pitting, delamination, abrasion, and burnishing). The severity of the damage was assigned a score of 0 to 4, with 0 indicating no damage and 4 indicating extreme damage. The extent of the damage was also assigned a score of 0 to 4, with 0 indicating 0% and 4 indicating 76% to 100%. An asymmetry ratio was calculated for each damage pattern to evaluate the uniformity of the distribution of the damage across each component.