Diagnostic strategies in osteomyelitis.

Technetium-99 (99Tc) pyrophosphate bone scanning often identifies patients with osteomyelitis before roentgenographic findings appear. However, recent studies have shown that 99Tc bone scanning often gives false-negative results, especially in neonates. The accuracy of computed tomographic scanning and indium-111 leukocyte scanning for diagnosis of early osteomyelitis has not been established. 99Tc bone scanning often gives false-positive results in patients with other conditions leading to bone injury and repair, such as trauma or recent surgery, further limiting the usefulness of this imaging procedure. Newer imaging techniques have not been adequately evaluated to establish their specificity. Because of their high cost and unproved accuracy, these new imaging procedures should not be routinely applied until their usefulness has been established. Bone biopsy remains the procedure of choice for establishing the diagnosis in patients suspected clinically to have osteomyelitis with negative findings on roentgenography and 99Tc bone scanning. Although Staphylococcus aureus is the leading cause of osteomyelitis, other pathogens cause 30 to 40 percent of cases. Aspiration or biopsy of the involved bone is usually required to choose appropriate antibiotic therapy. Bone biopsy is essential in chronic osteomyelitis, since cultures of sinus drainage are unreliable. Osteomyelitis in diabetics with foot infection and in association with decubitus ulcers presents special problems. Radionuclide scanning often give false-positive results in these patients. Proper diagnosis usually requires careful assessment of clinical and roentgenographic findings. Although bone biopsy seems useful in diagnosing osteomyelitis underlying decubitus ulcers, its role in diabetic patients with foot infections is not established. I do not recommend biopsy of foot bones in diabetic patients, since culture of bone biopsy specimens often give unreliable results in these situations because of contamination with ulcer organisms.