Chronic multifocal osteomyelitis, left tibia and fibula

This diagnosis code signifies a persistent, long-standing infection of the bone and bone marrow affecting multiple distinct sites within the left tibia and fibula. It indicates a chronic inflammatory process, often characterized by periods of remission and exacerbation, involving both lower leg bones on the left side.

Use this code when documentation clearly states chronic osteomyelitis affecting multiple foci within the left tibia and fibula. Supporting documentation would include imaging reports (e.g., X-ray, MRI, bone scan) showing multifocal involvement, pathology reports confirming chronic infection, and clinical notes detailing persistent symptoms and treatment for chronic osteomyelitis in these specific bones.

• Ensure the documentation specifies "chronic" and "multifocal" involvement of both the left tibia and fibula.
• Distinguish from acute osteomyelitis (M86.1-) or subacute osteomyelitis (M86.2-).
• Always sequence this code after any underlying cause of the osteomyelitis, if known and documented (e.g., open fracture, surgical complication).