Other secondary osteonecrosis, left fibula

This code signifies the death of bone tissue in the left fibula due to an underlying medical condition or external factor, rather than a primary idiopathic cause. This bone death results from a loss of blood supply to the affected area, leading to structural collapse and potential joint dysfunction.

Apply this code when documentation explicitly states osteonecrosis of the left fibula is secondary to another condition, such as corticosteroid use, trauma, sickle cell disease, or alcoholism. Ensure the physician's notes clearly differentiate it from primary (idiopathic) osteonecrosis.

• Confirm the laterality is specifically "left" and the bone is the "fibula."
• Always code the underlying cause of the secondary osteonecrosis first, if known and documented.
• Distinguish carefully from primary osteonecrosis (M87.0-) and other specified osteonecrosis (M87.8-).