How useful is ultrasonography in suspected acute osteomyelitis?

Sonographically detected subperiosteal fluid and periosteal irregularity have recently been proposed as diagnostic features of osteomyelitis. The purpose of this study was to determine the diagnostic accuracy of ultrasonography for suspected osteomyelitis. Nineteen patients were investigated prospectively with high-resolution ultrasonography for the presence of subperiosteal fluid or cortical irregularity. Diagnosis was established by surgery (three cases) or by results of other tests and clinical follow-up. Sixteen patients were diagnosed as having osteomyelitis, with positive ultrasonography in ten (sensitivity = 63%). Two ultrasonographic studies were false-positive; diagnostic accuracy was 58%. Thus, ultrasonographic results may be potentially misleading, emphasizing the importance of clinical judgment and results of other tests.