Spontaneous rupture of extensor tendons, right thigh

This code signifies a non-traumatic tear of the extensor tendons located in the right thigh. This typically involves the quadriceps tendon or patellar tendon, occurring without an external force or injury. The rupture leads to a loss of the ability to extend the knee joint.

Apply this code when documentation clearly states a "spontaneous rupture" or "atraumatic rupture" of the extensor tendons in the right thigh. This diagnosis is supported by clinical findings such as a palpable defect, inability to actively extend the knee, and imaging studies (e.g., MRI) confirming the tendon tear without evidence of trauma.

• Ensure the documentation specifies "spontaneous" or "atraumatic" to differentiate from traumatic ruptures.
• Verify the laterality (right thigh) is explicitly stated in the medical record.
• Do not confuse with M66.252 (left thigh) or M66.259 (unspecified thigh).