Idiopathic aseptic necrosis of bone, other site

This code signifies the death of bone tissue due to a lack of blood supply (avascular necrosis) where the underlying cause is unknown (idiopathic) and not due to infection (aseptic). It specifically applies when this condition affects a bone site other than those with more specific codes, such as the femoral head, humeral head, or carpal bones.

Use this code when documentation clearly states idiopathic aseptic necrosis affecting a bone not otherwise specified, such as the tibia, fibula, or metatarsals. Supporting documentation will typically include imaging reports (MRI, X-ray) confirming avascular necrosis and clinical notes ruling out trauma, steroid use, or other known causes.

• Ensure the documentation explicitly states "idiopathic" or "avascular necrosis of unknown etiology" to justify this code.
• Always check for more specific codes within the M87.0 subcategory if the affected bone is clearly identified (e.g., M87.01- for femur, M87.02- for humerus).
• Do not use this code if the avascular necrosis is secondary to trauma, drug-induced, or due to other known causes; instead, refer to codes within M87.1-M87.3.