Spontaneous rupture of extensor tendons, unspecified hand

This code signifies a non-traumatic tear or break in the extensor tendons of an unspecified hand, occurring without an external force or injury. It describes a condition where the tendon spontaneously fails, leading to impaired extension of the fingers or wrist.

Apply this code when documentation clearly states a spontaneous rupture of an extensor tendon in the hand, and the specific hand (right or left) is not identified. This typically occurs in patients with underlying conditions such as rheumatoid arthritis or chronic tenosynovitis that weaken the tendon structure.

• Ensure documentation specifies "spontaneous" and not traumatic rupture; traumatic ruptures are coded differently.
• Avoid using this code if the laterality (right or left hand) is documented; instead, use the more specific M66.241 or M66.242.
• Look for associated underlying conditions (e.g., rheumatoid arthritis) which may require additional coding as a primary or secondary diagnosis.