Idiopathic aseptic necrosis of unspecified bone

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 the specific bone affected is not documented. It represents a non-infectious bone infarction.

Apply this code when documentation clearly states idiopathic aseptic necrosis but does not specify the affected bone. This is typically used when diagnostic imaging (e.g., MRI, X-ray) confirms avascular necrosis, and a thorough workup has failed to identify a secondary cause.

• Avoid using this code if the affected bone is known; instead, use a more specific code from the M87.0- subcategory.
• Ensure documentation explicitly states "idiopathic" or "aseptic" and that no other underlying cause (e.g., trauma, steroid use, sickle cell disease) has been identified.
• If a specific bone is mentioned, even if the cause is idiopathic, a more precise code (e.g., M87.01- for femur) should be selected.