Classification of subacute osteomyelitis: type 1, central metaphyseal lesion; type 2, eccentric metaphyseal lesion with cortical erosion; type 3, diaphyseal cortical lesion; type 4, diaphyseal lesion with periosteal new bone formation, but without definite bony lesion; type 5, primary subacute epiphyseal osteomyelitis; and type 6, subacute osteomyelitis crossing physis to involve metaphysis and epiphysis.