Figure 4 Magnetic resonance imaging (MRI) shows increased acetabular cartilage width in the weight-bearing region following periacetabular osteotomy (PAO): representative cases with bilateral developmental dysplasia of the hip (DDH) (Neusoft Medical image diagnostic reporting system; Neusoft Co Ltd, Shenyang, China). MRI of 2 patients with bilateral developmental dysplasia of the hip show pre- and postoperative changes in acetabular cartilage width. Patient 1: a 25-year-old woman. (A) Preoperatively, the cartilage width in the acetabular weight-bearing area was 20.82 mm in the left hip and 23.24 mm in the right hip. (B) At the 37-month follow-up, the cartilage width increased to 23.71 mm in the left hip and 26.32 mm in the right hip. Patient 2: a 28-year-old woman. (C) Preoperatively, the cartilage width was 18.29 mm in the left hip and 21.66 mm in the right hip. (D) At the 41-month follow-up, the cartilage width increased to 21.90 mm in the left hip and 24.33 mm in the right hip.