Other secondary osteonecrosis of unspecified carpus

This code signifies bone death in an unspecified carpal bone that is not due to primary causes, but rather secondary to another underlying condition. This osteonecrosis results from an interruption of blood supply to the carpal bone, leading to cellular death and potential collapse of the bone structure.

Apply this code when documentation indicates avascular necrosis of a carpal bone, and the etiology is clearly secondary (e.g., trauma, steroid use, systemic disease), but the specific carpal bone affected is not specified. Supporting documentation would include imaging reports (X-ray, MRI) confirming osteonecrosis and physician notes detailing the secondary cause.

• Ensure the documentation explicitly states "secondary" osteonecrosis; otherwise, consider primary osteonecrosis codes.
• Avoid using this code if the specific carpal bone (e.g., lunate, scaphoid) is identified; instead, use a more specific code from the M87.33- subcategory.
• Always code the underlying secondary condition first, as it is the etiology of the osteonecrosis.