Patellofemoral arthritis is a relatively common condition, affecting up to 24% of women and 11% of men over the age of fifty-five years who have symptomatic osteoarthritis of the knee. Isolated patellofemoral arthritis is not as prevalent and has been reported to occur in 9% of radiographs of symptomatic knees in individuals over the age of forty years. Approximately 75% of all patellofemoral arthroplasties are done in women, and the increased frequency of patellofemoral disease may be related to the frequency of knee malalignment and dysplasia in women, although some studies have noted no sex-specific differences in knee kinematics.