Osteonecrosis in diseases classified elsewhere, unsp hand

This code describes the death of bone tissue in an unspecified hand due to an underlying medical condition. This osteonecrosis is a secondary manifestation of another disease process, rather than a primary bone disorder. It indicates localized bone death without specifying the exact bone or joint affected within the hand.

Use this code when documentation clearly states osteonecrosis of the hand, but the specific bone (e.g., scaphoid, lunate) is not identified, and an underlying systemic disease is the cause. This code is appropriate when the medical record explicitly links the osteonecrosis to another classified disease, such as lupus, sickle cell anemia, or corticosteroid use.

• Always sequence the underlying disease causing the osteonecrosis first, as this code is for "diseases classified elsewhere."
• Avoid using this code if a more specific anatomical site within the hand (e.g., M90.541 for right hand, M90.542 for left hand) is documented.
• Ensure the documentation specifies "unspecified hand" or lacks laterality to justify this code over a more specific laterality.