<s>[INST] My 4 year old grandson was diagnosed with Legg Perthes(?) today. The ball of the hip joint is completely gone. He woke up in pain weekend before last, could not walk all that day. Symptoms disappeared by next day. Was seen by his Dr. and referred to specialist. The diagnosis was given today. What does this mean and how could this happen so quickly? Parents are very vigilant and careful, little one is very active. [/INST] Legg-Calve-Perthes disease (LCPD) is idiopathic avascular necrosis (osteoporosis) of the capital epiphysis of the femoral head. Etiology is unclear, but it is likely caused by an interruption of the blood supply to the capital femoral epiphysis. There may be an associated hypercoagulability state (factor V Leiden).LCPD commonly presents in patients 3 to 12 years of age, with a mean age of 7 years. It is four to five times more common in boys. Usually LCPD is a self limiting disease, followed through a pediatric orthopedist. Treatment is basically for pain and restoration of the hip movement. Containment is important in treatment. non-surgical containment include casts and orthoses. Whereas surgical containment is accomplished with osteotomies of the proximal femur and pelvis. E short-term prognosis is determined by the magnitude of the femoral head deformity an her healing has completed. It is improved by early diagnosis, good follow-up, and compliance with the treatment plan </s>