In Cierny-Mader classification of chronic osteomyelitis, a Stage III lesion in a Class B (compromised) host describes:

• A Medullary osteomyelitis confined to the endosteal surface in a healthy patient
• B Diffuse osteomyelitis involving both cortices with mechanical instability in a healthy patient
• C Localized cortical sequestrum or dead-bone segment in a patient with vascular insufficiency ✓
• D Superficial infection limited to the cortical bone surface in a compromised host

Explanation

Cierny-Mader combines anatomical stage (I–IV) with physiological class: I = medullary, II = superficial, III = localized (cortical sequestrum, stable), IV = diffuse (both cortices, unstable). Class A = normal host; Class B = compromised (local — BL, or systemic — BS); Class C = treatment worse than disease. Stage III/Class B = localized cortical sequestrum in a compromised host (e.g. diabetic with peripheral vascular disease). Stage IV/Class B would have diffuse involvement with instability. The Cierny-Mader system guides surgical planning — Stage III/B typically requires sequestrectomy, debridement, and dead-space management.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.