Background In recent years,the number of patients undergoing primary total knee arthroplasty in China has rapidly increased.However,the incidence of primary total knee arthroplasty is unknown.The purpose of this study was to investigate the sex,age and,annual incidence of primary total knee arthroplasty based on 3118 Chinese patients who underwent the procedure during the period of 2000-2011.Methods Total knee arthroplasties were performed on 511 males and 2607 females in our hospital during the period of 2000-2011.The sex,age,and annual incidence of primary total knee arthroplasty were evaluated.Results The annual incidence of primary total knee arthroplasty increased from 35 knees in 2000 to 681 knees in 2011.The average annual percentage increase in incidence was 33.2％.Females accounted for 83.2％ of the patients who underwent primary total knee arthroplasty.In both males and females,the highest incidence was observed in the group aged 65-74 years.Conclusions This study demonstrated a rapid increase in the incidence of primary total knee arthroplasty in our Chinese study population.The sex and age incidence of primary total knee arthroplasty in our study population differed from those reported in West populations.