Osteoarthritis is the most common disease of the elderly and is usually characterized by medial knee wear, so years of osteoarthritis can lead to inversion deformity of the knee, causing severe pain and difficulty walking. A 74-year-old female patient with osteoarthritis with bilateral inversion deformity X-ray shows severe medial wear on both knees, and full-length radiographs suggest severe inversion deformity Bilateral simultaneous knee arthroplasty, with weight-bearing on the third day after surgery, the inversion deformity disappeared and normal force was restored One week after surgery Knee function recovery Bilateral simultaneous knee arthroplasty The knee inversion deformity disappeared and the normal force line was restored on the third day after surgery.