Abstract： INTRODUCTION Restoring mechanical alignment and soft tissue balance in total knee arthroplasty (TKA) for valgus knees depend on the origin of deformity and soft tissue status.[1-3] Valgus deformity can exist during knee flexion besides extension,which could lead to patellofemoraljoint instability and soft tissue imbalance in the flexion gap,and thus complicate the surgical procedures.Valgus deformity during knee flexion can be measured by radiographic analysis using long-film radiograph and computed tomography (CT) scans.[4] It usually results from a bone defect in the posterior part of the lateral femoral condyle (measured on CT scan) or valgus deformity in the tibia (measured on long-film radiograph).However,it is difficult to inspect this deformity during the physical examination.