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Question: A patient came in to see a provider due to foot pain. The provider listed “pes planus” as the diagnosis. When I look up that phrase in the ICD-10-CM code book, there’s an Excludes1 note for the congenital version of the condition. How do I know which code to pick?

Montana Subscriber

Answer: In a situation like this, you’re looking for a clinical distinction, and not just a coding distinction. If you cannot find previous references to pes planus (or flat feet) in the notation, where the provider mentions whether the condition is congenital or acquired, then you should query for more information.

Once you have what you need, go to the ICD-10-CM code book.

Looking up pes planus is tricky, because it’s the bracketed name for the condition of flat foot. So, if you look up flat foot, you’ll find it under the parent code M21 (Other acquired deformities of limbs). You’ll find M21.4- (Flat foot [pes planus] (acquired)), but, as you mentioned, you’ll find an Excludes1 note for congenital flat feet, which points you toward Q66.5- (Congenital pes planus). These codes all require an additional character to describe laterality.

If the provider says the condition is congenital for the patient, choose a code from the Q66.5- family. If the provider says the condition has been acquired, look to M21.4-.

Rachel Dorrell, MA, MS, CPC-A, CPPM, Production Editor, AAPC