Idiopathic aseptic necrosis of unspecified foot

This code signifies the spontaneous death of bone tissue in an unspecified foot due to a lack of blood supply, without an identifiable cause such as trauma or infection. This condition, also known as avascular necrosis, leads to bone collapse and subsequent arthritis.

Apply this code when documentation clearly indicates idiopathic avascular necrosis affecting any part of the foot, and the specific foot (right or left) is not specified. This diagnosis is typically made based on imaging studies (e.g., MRI, X-ray) showing bone infarction and clinical symptoms like pain and limited mobility.

• Ensure documentation specifies "idiopathic" or "aseptic" necrosis to differentiate from other causes.
• Avoid using this code if the specific foot (right or left) is documented; instead, use the more specific M87.071 or M87.072.
• Always review the patient's medical record for any underlying conditions that might explain the necrosis, as this could lead to a more specific code.