Fig. 1.

a A 7-year-old boy with right Herring C Perthes’ disease treated with an Atlanta brace. b A year and a half later, severe flattening of the femoral head was present with “hinge abduction”. c Six weeks after valgus extension femoral osteotomy (VGEO) of the affected hip. d Four years later, the neck-shaft angle measured 140°, the boy had resumed full sport activity, and the range of motion of the hip showed only 10° limitation of internal rotation. e Maximum hip abduction was measured to be 40° on the right and 43° on the left (normal) side. The hip was still remodeling, and it was classified as Stulberg II–III. Case 3 in Table 1