Update on the diagnosis and management of osteomyelitis.

Osteomyelitis can be classified by duration, pathogenesis, location, extent, and host status. Bone infections are currently classified by the Waldvogel or the Cierny-Mader classification. Because the Waldvogel classification is an etiologic system and the Cierny-Mader classification is descriptive, both classifications can be simultaneously used. The Cierny-Mader classification is based on the anatomy of the bone infection and the physiology of the host. Cierny-Mader staging allows stratification of long bone osteomyelitis and the development of comprehensive treatment guidelines for each stage. Current trends in long bone osteomyelitis therapy emphasize early diagnosis and aggressive treatment. Radiographs and bone cultures are the mainstays of diagnosis. Imaging with radionuclide scans, computerized tomography, and magnetic resonance imaging are used when the diagnosis of osteomyelitis is equivocal or to help guage the extent bone and soft tissue infection. Surgical treatment involves débridement of necrotic bone and tissue, obtaining appropriate cultures, managing dead space, and, when necessary, obtaining bone stability. Medical therapy includes improving any host deficiencies, initial antibiotic selection, and antibiotic modification based on culture results. Antibiotic delivery has expanded to include effective oral agents and local therapy with antibiotics mixed in polymethylmethacrylate. Cierny-Mader staging was developed to describe long bone osteomyelitis. This staging system has to be modified to describe diabetic foot osteomyelitis and vertebral osteomyelitis. Osteomyelitis in patients with diabetes mellitus involves the bones of the feet or ankles. The vascular and neurologic status of the patient must be carefully accessed. Patients may be managed with local débridement surgery or ablative surgery plus 2 to 4 weeks of antibiotic therapy depending on whether all of the osteomyelitis is surgically removed. If the patient does not wish surgery or is not a surgical candidate, suppressive antibiotic therapy can be used. Vertebral osteomyelitis is usually hematogenous in origin. The diagnosis is made by bone cultures, histology, and radiographs. Magnetic resonance imaging and technetium scans are useful in making the diagnosis and in gauging the extent of the bone and soft tissue infection. Therapy requires parenteral antibiotic therapy and may include early surgery and stabilization. The choice of an antibiotic therapy is guided by the bone biopsy or débridement culture results.