Background: Anterior knee pain(AKP) was a common complication after total knee replacement(TKR). This condition can be occurred in both patellar resurfacing and non-resurfacing technique. An increase in patellar thickness 1 mm or more postoperatively was associated with lower gain in WOMAC score. Objective:To compare AKP and up and down stair function after patellar thickness reduction and patellar non-resurfacing TKR. Materials and Methods:A retrospective comparative study of was designed. All patients who had been TKR since March 2015 and December 2017 were included. The questionnaires of 2 easy questions about pain over patellar region and walking up-down stairs performance were sent to all patients by letters. The patient's characteristics were collected from inpatient medical records. AKP was defi ned as pain scale 3-10. Data were analyzed by t-test and fi sher's exact using STATA 12 (demonstrated version). P-value < 0.05 was considered signifi cant.Results: 60 questionnaires were sent and 49 evaluations were received. 26 patients were patellar non-resurfacing(PNR) group and 23 patients was patellar thickness reduction(PTR) group. Duration after TKR to questionnaires response were 12-43 months. The prevalence of AKP and knee function of up and down stair were not signifi cantly different in both groups. The severity of AKP in PNR group (5.1+1.2) was signifi cant (p-value < 0.01) higher than PTR group (3.4+0.8).Conclusion: Patellar thickness reduction in total knee replacement could reduce the severity of anterior knee pain compared to patellar non-resurfacing technique.