Radiographic findings include periosteal thickening or elevation, as well as cortical thickening, sclerosis, and irregularity. Other changes include loss of trabecular architecture, osteolysis, and new bone formation. These changes may not be evident until 5-7 days in children and 10-14 days in adults. Plain films show lytic changes after at least 50%-75% of the bone matrix is destroyed. Therefore, negative radiographic studies do not exclude the diagnosis of acute osteomyelitis.