Osteonecrosis in diseases classified elsewhere, unsp site

This code signifies the death of bone tissue due to a loss of blood supply, occurring as a secondary manifestation of another underlying disease process. It indicates that the specific anatomical location of the osteonecrosis has not been documented or is not specified.

Use this code when documentation confirms osteonecrosis is present and is explicitly linked to another systemic disease (e.g., lupus, sickle cell anemia, chronic steroid use), but the affected bone site is not identified. This code is appropriate when the physician's notes state "osteonecrosis secondary to [disease], site unspecified."

• Always sequence the underlying systemic disease first, as this code represents a manifestation.
• Avoid using this code if a specific anatomical site of osteonecrosis is documented; instead, use the more specific M90.5- subcategory code.
• Query the provider for a more specific site if possible to improve coding accuracy and specificity.