Orthopedic Coding Alert

Don’t miss this Excludes2 note.

A complete rupture of the Achilles’ tendon often occurs spontaneously during sports, without a pre-existing tendonitis. A complete rupture requires surgery to reconstruct the torn edges of the tendon or sometimes repair the tendon back to the bone. 

You should report this condition with one of the following ICD-10-CM codes:

• M66.361, Spontaneous rupture of flexor tendons, right lower leg
• M66.362, ... left lower leg
• M66.369, ... unspecified lower leg.

ICD-10-CM gives you three codes based on anatomical site (right lower leg, left lower leg, and unspecified).

Documentation: Your physician most likely already documents the side of the Achilles tendon rupture, so now have you a way of specifying this with a diagnosis code. Although you have a code for unspecified, you should always code to the highest specificity.

Here is how you will find these codes in the Alphabetic Index:

Rupture, ruptured

- tendon (traumatic) —see Strain
- - nontraumatic (spontaneous)
- - - flexor M66.30
- - - - lower leg M66.36-

Coder tips: Underneath the M66 (Spontaneous rupture of synovium and tendon) category, you will find the following notations:

• Note: a spontaneous rupture is one that occurs when a normal force is applied to tissues that are inferred to have less than normal strength
• Excludes2: rotator cuff syndrome (M75.1) and rupture where an abnormal force is applied to normal tissue - see injury of tendon by body region.