Idiopathic aseptic necrosis of right femur

This code signifies the death of bone tissue in the right femur due to a lack of blood supply, without an identifiable cause such as trauma or infection. This condition, also known as avascular necrosis (AVN) or osteonecrosis, leads to bone collapse and subsequent arthritis.

Apply this code when documentation explicitly states idiopathic avascular necrosis or osteonecrosis affecting the right femur. Supporting documentation should include imaging findings (e.g., MRI, X-ray) confirming bone death and a physician's assessment ruling out secondary causes.

• Ensure laterality is clearly documented (right vs. left vs. bilateral).
• Distinguish from traumatic osteonecrosis (S72.xx) or osteonecrosis due to other specified causes (M87.1-M87.8).
• Code any associated pathological fractures separately if documented.