Does this Patient with Diabetes have Osteomyelitis?

• Diagnosis of lower extremity osteomyelitis in the diabetic patient remains challenging
• Bone biopsy with culture remains the gold standard for diagnosis but is not always obtainable
• What clinical features, therefore, raise the likelihood of osteomyelitis?
• In this review, an ulcer size > 2 cm² (LR 7.2), ability to probe to bone using a sterile stainless steel probe (LR 6.4), and an ESR > 70 mm/h were found to be useful in predicting the presence of osteomyelitis
• Clinical features NOT found to be useful included fever (sensitivity 19%), presence of erythema, swelling, or purulence (LR 1), elevated white blood cell count (sensitvity 14%-54%), and superficial swab culture
• A note about radiographic studies:
  • bony changes on plain films may take up to 2 weeks to develop
  • plain films alone are only marginally useful if positive (LR 2.3)
  • MRI is more accurate than bone scan or plain films
  • If you are going to order a radiographic study, your best bet is the MRI

References

Butalia S, Palda VA, Sargeant RJ, et al. Does this patient with diabetes have osteomyelitis of the lower extremity? JAMA 2008;299:806-13.