Decrease in angle of head and neck to shaft of femur (<125 degrees). Thought to be due to a defect in ossification/development of femoral neck. Bilateral in up to 50%. Usually present between ages 2 to 6. Lurching/waddling gait type gait that is not painful – may just be a limp if unilateral. Abduction and internal rotation of leg is restricted. Genu valgum is common.Classification: 1) Congenital 2) Proximal femoral foral deficiency (PFFD) 3) Acquired (eg #, rickets; SCFE) 4) DevelopmentSurgical management indicated if significant/severe.