Orthopedic Coding Alert

Question: My provider is treating a dancer who has pes planovalgus. The surgeon stated it was acquired, but I queried them because their documentation does not state a cause for the acquired flat foot. They do not state in their documentation acquired or congenital, and they do not document “this is what caused the flat foot” (like arthritis due to dancing or something.) I do not see a rubric for “code x if not specified,” so I’m at a loss. Any suggestions? I’ve already inquired, and they say, “It is unknown if they were born with flat feet, without having their pediatric evaluation.” My thinking is to default to congenital unless we know a cause, but maybe I’m wrong?

Pennsylvania Subscriber

Answer: Congenital and acquired flat feet are two different conditions that affect the foot arches. When a patient suffers from flat feet (also called pes planus or colloquially as fallen arches), the arches, or medial borders, of their feet have collapsed, with the entire sole of the foot coming into complete, or near complete, contact with the ground.

Congenital flat feet are present at birth and are caused by abnormalities in the structure of the foot. The ICD-10 code for congenital flat feet is Q66.5- (Congenital pes planus). When coding for congenital flat feet, it’s important to specify the type of flat foot, such as flexible, rigid, or unspecified. Here are some examples for coding congenital flat feet:

• Q66.50 (Congenital pes planus, unspecified foot)
• Q66.51 (… right foot)
• Q66.52 (… left foot)

Additional codes may be used to describe any associated conditions or complications.

Acquired flat feet develop over time and are usually caused by factors such as injury, arthritis, or tendon dysfunction. The ICD-10 code for acquired flat feet is M21.4- (Flat Foot [pes planus] (acquired)):

• M21.40 (Flat Foot [pes planus] (acquired), unspecified foot)
• M21.41 (… right foot)
• M21.42 (… left foot)

When coding for acquired flat feet, it’s important to document the underlying cause or condition that led to their development. Additional codes may be used to describe any associated conditions or complications.

To code the patient’s condition correctly, you may need to query the practitioner to fully understand if the patient acquired this condition later in life or if they were, in fact, born with flat feet.