There is no known way to prevent Legge-Calve-Perthes disease.
About 50% of children, even with no treatment, will do well. The other half of affected children may have arthritis even as teenagers. The older the child at the time of onset, the worse the outcome. Prognosis is especially poor if the femoral head cannot fit securely in the pelvis.
Legge-Calve-Perthes disease is not contagious, and poses no risk to others.