Other acute osteomyelitis, unspecified tibia and fibula

This code signifies an acute inflammatory process of the bone and bone marrow affecting the lower leg, specifically the tibia and/or fibula, where the exact cause or type of osteomyelitis is not specified. It indicates a recent onset infection, rather than a chronic condition.

Apply this code when documentation clearly states "acute osteomyelitis" of the tibia, fibula, or both, but lacks further specificity regarding the organism or specific type (e.g., hematogenous, contiguous). This code is appropriate when the medical record does not differentiate between the left or right lower leg.

• Ensure documentation specifies "acute" to differentiate from chronic osteomyelitis (M86.2-).
• If the specific organism causing the osteomyelitis is identified, a secondary code from B95-B97 should be assigned.
• Avoid using this code if laterality (left or right) is documented; instead, choose a more specific code from M86.161-M86.163.