M21.4 — Flat foot [pes planus] (acquired)
M21.4 is a non-billable header ICD-10-CM code for flat foot [pes planus] (acquired). It cannot be billed on its own: choose one of the more specific child codes below.
Excludes1 — never code together
These conditions cannot occur together. Billing both on the same encounter is a denial.
- congenital pes planus (Q66.5-)
Other codes that can never be billed with M21.4
These codes carry an Excludes1 note pointing at M21.4. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading M21.4 alone.
- Q66.5Congenital pes planus
Risk adjustment
M21.4 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.
Code to one of these instead M21.4
3 child codes. Green means billable.
Related codes at this level
Codes that share M21. If M21.4 is not quite right, the correct code is usually one of these.
- M21.0Valgus deformity, not elsewhere classified
- M21.1Varus deformity, not elsewhere classified
- M21.2Flexion deformity
- M21.3Wrist or foot drop (acquired)
- M21.5Acquired clawhand, clubhand, clawfoot and clubfoot
- M21.6Other acquired deformities of foot
- M21.7Unequal limb length (acquired)
- M21.8Other specified acquired deformities of limbs
- M21.9Unspecified acquired deformity of limb and hand
Questions about M21.4
- Is M21.4 a billable ICD-10-CM code?
- No. M21.4 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
- Where does M21.4 sit in the tabular list?
- Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Other joint disorders (M20-M25).
- What cannot be coded together with M21.4?
- M21.4 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.