Idiopathic aseptic necrosis of right tibia

This code signifies the spontaneous death of bone tissue in the right tibia due to a lack of blood supply, without an identifiable underlying cause such as trauma, infection, or systemic disease. This condition, also known as osteonecrosis or avascular necrosis, leads to bone collapse and joint destruction over time.

Apply this code when documentation explicitly states idiopathic aseptic necrosis affecting the right tibia. Supporting documentation should include imaging reports (e.g., MRI, X-ray) confirming osteonecrosis and a physician's note ruling out secondary causes. This code is appropriate for both initial diagnosis and subsequent encounters for this specific condition.

• Ensure "idiopathic" or "primary" is documented; otherwise, investigate for a secondary cause.
• Verify laterality (right tibia) is clearly stated in the medical record.
• Do not confuse with osteomyelitis or stress fractures, which have different etiologies.