Total knee arthroplasty(TKA) is a successful orthopedic surgery with excellent clinical outcome and survival. However, there are concerns about patient satisfaction in previous reports, and dissatisfaction rate of 15-30% is reported in clinical outcomes(PROMs) of some studies. Therefore, for improving the patient's outcome and satisfaction after total knee arthroplasty, it is necessary to change the design of the conventional total knee arthroplsaty implant. The knee is a joint structure with several dynamic functions, and not only the skeletal structure but also the soft tissue balance plays an important role in the function of the knee joint. New implants are being developed to overcome the limitations of conventional TKA implant, including the Journey II Bi-cruciate substituting total knee system (JII-BCS; Smith & Nephew). JII-BCS implant has normal articular geometry, more anatomical femoral shape, lateral tibial convex geometry, and asymmetrical tibial plateau, anterior and posterior cams, which has been shown in experimental studies to produce nearly normal knee movement by reproducing the actual normal anatomical alignment in vivo.

The clinical results of the kinematic effects of this anatomcally aligned change are insufficient, and there is also a lack of comparative studies with conventional total knee arthroplasty implant. The purpose of this study is to compare outcomes between anatomically aligned TKA(JII-BCS) and conventional TKA(Legion total knee system, Smith & Nephew). This study is a randomized controlled study in patients undergoing same-day bilateral total knee arthroplasty. A patient undergoing same-day bilateral total knee arthroplasty will use a random number to determine the instruments(JII-BCS or Legion), and both knee joints will be operated with the same instruments. Radiologic parameter, patients preference and clinical results was investigated in patients who received TKA during minimum 2 year follow up.

Inclusion Criteria:

• Patients for bilateral total knee arthroplasty
• having medicare insurance

Exclusion Criteria:

• Rheumatoid arthritis
• Other inflammatory arthritis
• Crystal-induced arthritis
• Septic arthritis
• Neuropsychiatric patients
• Previous knee operation history
• Neuropsychiatric patients
• Patients with preoperative severe limitation of motion (Flexion contracture ≥ 20, range of motion ≤ 90)
• Patients with preoperative severe defomity of knee alignment (Varus or valgus angle ≥ 15)
• Severe obese patients (BMI ≥ 40)