Fig. 4

a Type 4 lesion in a 28-year-old man. The entire femur was affected by fibrous dysplasia. The neck-shaft angle was 130°. Varus deformity was present in the proximal femoral shaft. The shaft cortex was thinner than normal. b The deformity was corrected with single-level valgus osteotomy at the vertex of the deformity. The femur alignment was restored to normal. c The osteotomy had not healed 9 months after the operation. d The osteotomy had not healed 16 months after the operation. e The two distal interlocking screws were removed 16 months after the osteotomy. f The osteotomy site healed 9 months after removing the screws. There was no recurrence or progression of the deformity 10 years later