Fig. 2

Three-dimensional measurement of the femoral head coverage, weight-bearing area, and intact area. a The acetabular rim line (in black) for determining the acetabular coverage and acetabular arch line (in red) for determining the weight-bearing area. b The acetabular coverage projected on the femoral head in yellow. c The weight-bearing area projected on the femoral head in yellow. d1–d3 The intact area in yellow of types A, B, and C1 was determined by removing the necrotic area in orange (top view)