[Ultrasonography of acute osteomyelitis of the long bones in children. Diagnostic and prognostic value].

Between 1991 and 1994, ultrasonography was used to investigate 90 consecutive children with acute osteomyelitis. Ultrasonographic findings were analyzed taking into account the time elapsed from first symptoms. Outcome in 47 children who were treated and followed for at least 6 months was also studied. Deep soft tissue swelling adjacent to the affected bone was found to be an early but nonspecific sign which persisted all along the course of the disease. Periosteal elevation smaller than 3 mm, secondary to exsudation or septic fluid, confirmed the disease in earliest stage and was the most frequent ultrasonographic sign in first three days of disease. Treated at that stage, total resolution was obtained in 66% of patients and stabilization, in 34% of cases, without any evolution toward chronicity. Acute osteomyelitis with subperiosteal abscess progressed toward stabilization in 66% of cases and toward chronic osteomyelitis in 8% of cases. 32% of subperiosteal abscess were ruptured; in such situation, progression to chronicity was observed in 26% of patients. Since ultrasonography has been used in our institution for the diagnosis of acute osteomyelitis, the rate of evolution to chronicity spectacularly dropped from 63% to 11%. The main advantage of ultrasonography is an earlier detection of subperiosteal collection that indicates surgical drainage without any delay.