Spontaneous rupture of flexor tendons, unspecified site

This code signifies a non-traumatic tear of a flexor tendon that occurs without an identifiable external force or injury. It indicates a spontaneous disruption of the tendon fibers responsible for bending a joint, where the specific anatomical location of the rupture is not documented.

Apply this code when documentation clearly states a spontaneous rupture of a flexor tendon, but the physician has not specified the exact body region (e.g., hand, wrist, foot). This code is appropriate when the etiology is degenerative or idiopathic, rather than acute trauma.

• Avoid using this code if the rupture is due to an acute injury; instead, select a code from the S66, S76, S86, or S96 series for traumatic tendon injuries.
• Always seek clarification from the provider if the site of the flexor tendon rupture is not specified, as more specific codes are available (e.g., M66.31-M66.39).
• Do not use this code for extensor tendon ruptures; refer to codes within the M66.2- series for spontaneous extensor tendon ruptures.