The presence of necrosis, crepitus, and foul odor in a diabetic foot ulcer indicates a severe soft tissue infection, likely necrotizing fasciitis or gas gangrene. This condition requires immediate surgical debridement to remove all necrotic tissue and halt the spread of infection. Intravenous broad-spectrum antibiotics are essential to control systemic infection and sepsis. Delay in surgical intervention significantly increases mortality and limb loss risk. Conservative measures alone are insufficient due to rapid progression. Early aggressive treatment is crucial for patient survival and limb salvage.

Reference: Harrison's Principles of Internal Medicine, Kasper et al., 20th Edition.