Orthopedic Coding Alert

Question: Notes indicate that the provider performed a level-three new patient evaluation and management (E/M) service for a patient with acquired unequal limb length. What is the proper ICD-10 code for unequal limb length?

Utah Subscriber

Answer: If you're unable to get more information - specifically, the anatomy and laterality of the limb length - then you'll append M21.70 (Unequal limb length (acquired), unspecified site) to 99203 (Office or other outpatient visit for the evaluation and management of a new patient, which requires these 3 key components: a detailed history; a detailed examination; medical decision making of low complexity ...).

You should, however, scour the encounter notes for evidence of the unequal limb, as ICD-10 breaks the condition into the following diagnosis groups:

• M21.72- - Unequal limb length (acquired), humerus
• M21.73- - Unequal limb length (acquired), ulna and radius
• M21.75- - Unequal limb length (acquired), femur
• M21.76- - Unequal limb length (acquired), tibia and fibula

Note: Once you get the correct limb, you can make your ICD-10 code even more specific by adding a sixth digit that represents the laterality of the injury. Apply the diagnosis code to the side of the body with the shorter limb. So, if a patient suffered from unequal limb length with a shorter right humerus, you'd report M21.721 (Unequal limb length (acquired), right humerus).