The patient’s severe bilateral knee valgus deformity and abnormal force lines in both lower extremities led to the development of bilateral knee osteoarthritis due to increased wear and tear. Knee joint replacement has very good surgical results for this kind of joint deformity with severe pain, and after the surgery, the patient can return to normal living condition, which fundamentally solves the discomfort of the knee joint and greatly improves the quality of life, thus allowing the elderly to be active and happy in their old age.