PURPOSE: To assess the incidence of lateral retinacular release (LRR), performed to improve patellar tracking in total knee arthroplasty according to tourniquet effect and design of femoral components. MATERIALS AND METHODS: From March 1999 to March 2004, we have evaluated the patellar tracking status based on "no thumb technique" with or without tourniquet inflation and calculated the frequency of LRR respectively in order to assess the tourniquet effect. In addition, we have examined the difference in the frequency of LRR according to the femoral component designs. RESULTS: Among 286 total knee arthroplasties, LRR was need in 241 cases (84.3%) under the inflated tourniquet, but only in 81 cases (28.3%) under deflated tourniquet. In Genesis II prosthesis, LRR was needed in 3 cases (9.7%) among the 31 cases after deflating tourniquet, but in 25 cases (80.6%) with inflating tourniquet. In Scorpio prosthesis, LRR was needed in 52cases (33.8%) among 154 cases after deflating tourniquet, but in 124 cases (80.5%) with inflating tourniquet. In the other prostheses, LRR was needed in 92 cases (91.1%) among 101 cases with inflating tourniquet inflation, but only in 26 cases (25.7%) after deflating tourniquet. CONCLUSION: The tourniquet application altered intraoperative patellofemoral tracking during total knee arthroplasty. The need for LRR should be evaluated after tourniquet deflation and the incidence of LRR is expected to reduce by 56% with this criteria. The frequency of LRR also could be influenced by femoral component designs.