Idiopathic aseptic necrosis of unspecified fibula

This code signifies the death of bone tissue in the fibula due to a lack of blood supply, without an identifiable cause such as trauma or infection. This condition, also known as avascular necrosis or osteonecrosis, leads to bone collapse and joint destruction over time. The "unspecified" designation indicates that the laterality (left or right fibula) is not documented.

Apply this code when documentation clearly states idiopathic aseptic necrosis of the fibula, and the medical record does not specify which fibula is affected. This diagnosis is typically made based on imaging studies (e.g., MRI, X-ray) and exclusion of other causes.

• Ensure the documentation explicitly states "idiopathic" or "aseptic" and specifies the fibula as the affected bone.
• Avoid using this code if the laterality (left or right fibula) is documented; instead, use the more specific codes M87.061 or M87.062.
• Query the provider if the cause of the aseptic necrosis is known (e.g., post-traumatic, drug-induced) to select a more specific code from the M87 category.