Flat foot [pes planus] (acquired)
Flat foot [pes planus] (acquired)
M21.4 is a header (parent) code in the ICD-10-CM hierarchy. It is not billable for claim submission. Use one of the billable child codes listed below.
Billable codes in this category
Each of the codes below is billable. Choose the one that most accurately describes the patient's diagnosis.
Acquired flat foot (pes planus) affecting an unspecified foot — meaning laterality was not documented or cannot be determined from the record.
Acquired collapse of the medial longitudinal arch of the right foot, coded specifically when pes planus developed after birth due to injury, tendon dysfunction, arthritis, or other acquired cause — not a structural anomaly present at birth.
Acquired collapse of the medial longitudinal arch of the left foot, documented as developing after birth due to an identifiable cause such as posterior tibial tendon dysfunction, trauma, or arthritis — not a congenital structural variant.
Inclusion & exclusion notes
Excludes 1 (mutually exclusive — never code together)
- congenital pes planus (Q66.5-)