Osteonecrosis due to previous trauma, unspecified ankle

This code signifies the death of bone tissue in an unspecified ankle joint, resulting from a prior traumatic injury. This condition, also known as avascular necrosis, occurs when the blood supply to the bone is disrupted, leading to bone collapse and potential joint destruction.

Assign this code when documentation clearly states osteonecrosis of the ankle is a direct consequence of a previously sustained trauma. This diagnosis is typically supported by imaging studies (e.g., MRI, X-ray) showing bone necrosis and a documented history of ankle injury.

• Ensure the documentation explicitly links the osteonecrosis to a previous trauma; current trauma would be coded differently.
• Verify laterality if specified in the documentation; this code is for an "unspecified ankle."
• Do not use this code if the osteonecrosis is due to other causes, such as steroid use or alcoholism; specific codes exist for those etiologies.