Within the female population, ethnicity was shown to have a Significant influence on the outcome of TKA as inferior results were reported by both Hispanic and African-American patients when compared to Caucasians. This effect is particularly marked in African-American women whose Knee Society Scores were 13% lower at follow-up compared to Caucasians. The differences in the perception of pain noted by the various ethnic groups proved to be a principal factor for outcomes following TKA among women. This study demonstrates that the ethnicity must be considered in assessing outcomes. Within the female population TKA appears to be less successful in Hispanic and African-American patients.