Adductor canal block and femoral nerve block are the most commonly used nerve blocks for pain control after total knee arthroplasty. The block area for adductor canal is a sensory branch near the knee area, which can potentially reduce the effect of motor blockage of quadriceps muscle. We try to proof adductor canal block can reduce the pain level after surgery effectively and preserve the muscle power of quadriceps muscle. Therefore, the rehabilitation course can be reduced and further lowering the risks of falling and complications.

Inclusion Criteria:

• Age at least 50 years old, not exceed 100 years old
• Diagnosed Primary Knee Osteoarthritis
• Accepted Total Knee Arthroplasty

Exclusion Criteria:

• Diagnosed Osteonecrosis
• Diagnosed inflammatory Arthritis、Rheumatoid Arthritis
• Accepted Revision Total Knee Arthroplasty
• Quadriceps muscle rupture, suture or repair history
• Neurological or orthopedic disorders that could affect quadriceps muscle power
• Allergy to amide anesthetics
• Patients who cannot obey or follow directions