Other secondary osteonecrosis, unspecified foot

This code signifies the death of bone tissue in an unspecified foot due to an underlying condition, rather than a primary bone disease or trauma. It indicates that the osteonecrosis is a consequence of another medical issue, such as steroid use, alcoholism, or systemic lupus erythematosus. The specific bone affected within the foot is not documented or known.

Apply this code when documentation clearly states "secondary osteonecrosis" affecting an unspecified foot, and the underlying cause is identified but the precise location within the foot is not specified. This is appropriate when imaging reports confirm osteonecrosis but cannot pinpoint a specific tarsal, metatarsal, or phalangeal bone.

• Always code the underlying systemic condition causing the secondary osteonecrosis first.
• Avoid using this code if a more specific anatomical site within the foot (e.g., talus, navicular) is documented; instead, use a more precise M87.37- subcategory.
• Ensure documentation differentiates between primary (idiopathic) osteonecrosis (M87.1-) and secondary osteonecrosis.