Other infective (teno)synovitis, unspecified ankle and foot

This code signifies inflammation of the synovial membrane and/or tendon sheath in an unspecified ankle or foot, caused by an infectious agent other than a specific bacterial or viral pathogen. It represents a non-specific infective process affecting these structures in the lower extremity.

Apply this code when documentation indicates infective tenosynovitis or synovitis of the ankle or foot, but the specific infectious organism is not identified or is not one with a more specific ICD-10-CM code. This code is appropriate when the laterality (right or left) of the affected ankle/foot is not specified in the medical record.

• Ensure documentation clearly states "infective" and not just "inflammatory" to differentiate from non-infectious tenosynovitis.
• Avoid this code if a more specific infectious agent (e.g., staphylococcal, gonococcal) is identified; use the appropriate organism-specific code.
• Prioritize codes specifying laterality (e.g., M65.171, M65.172) if documented. Only use the "unspecified" code when laterality is truly unknown.