Spontaneous rupture of flexor tendons, unsp ankle and foot

This code signifies a non-traumatic tear of a flexor tendon in an unspecified ankle or foot. It indicates that the tendon rupture occurred without an external force or injury, often due to degenerative changes, inflammatory conditions, or overuse.

Apply this code when documentation clearly states a "spontaneous" or "atraumatic" rupture of a flexor tendon in the ankle or foot, without specifying laterality. This code is appropriate when the physician's notes confirm the absence of an acute injury or external trauma as the cause of the rupture.

• Ensure documentation explicitly states "spontaneous" or "atraumatic" to differentiate from traumatic ruptures.
• Avoid using this code if laterality (right or left) of the ankle/foot is specified; instead, use the more specific M66.371, M66.372, or M66.373.
• Query the provider if the cause of the rupture is unclear or if trauma is mentioned, to determine if a traumatic tendon injury code (e.g., S96.-) is more appropriate.