Knee maturation as a differentiating sign between congenital rubella and cytomegalovirus infections.

Knee epiphyseal maturation is retarded in most neonates with congenital rubella infection, whereas neonates with congenital cytomegalovirus infection have relatively normal maturation. Asse-sment of knee maturation is useful in differentiating rubella from cytomegalovirus infection in the neonate.