Spontaneous rupture of extensor tendons, left hand

This code signifies a non-traumatic tear or break in the extensor tendons located in the left hand. This rupture occurs without an external force or injury, often due to underlying degenerative changes, inflammatory conditions, or chronic overuse. It typically results in impaired extension of the fingers or wrist.

Apply this code when documentation clearly indicates a spontaneous (non-traumatic) rupture of one or more extensor tendons in the patient's left hand. This diagnosis is supported by clinical examination findings consistent with extensor tendon disruption and often confirmed by imaging studies such as ultrasound or MRI.

• Differentiate from traumatic ruptures (S66.4-S66.5 series) which require an external injury.
• Ensure laterality (left hand) is explicitly documented; do not assume.
• If the rupture is due to an underlying systemic disease (e.g., rheumatoid arthritis), code the underlying condition first, followed by this code.