A 62-year-old diabetic man has a deep plantar ulcer over the first metatarsal head that probes to bone. Plain radiographs show no destructive change. Inflammatory markers are mildly raised. What is the reference standard investigation to confirm underlying osteomyelitis before planning the extent of debridement?

• A MRI of the foot
• B Three-phase technetium-99m bone scan
• C FDG-PET scan
• D Bone culture and histopathology from a biopsy specimen ✓

Explanation

Bone biopsy with culture and histological examination remains the reference standard for diagnosing diabetic foot osteomyelitis because it identifies the causative organism and distinguishes infection from neuropathic change, directly guiding antibiotic choice and extent of resection. MRI is the most useful imaging modality and is highly sensitive, but marrow edema from neuropathic arthropathy or recent ulceration produces false positives. Bone scans lack specificity in the diabetic foot, and PET is not routinely available or organism-directed.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.