M21.6Other acquired deformities of foot

M21.6 is the ICD-10-CM diagnosis code for other acquired deformities of foot. It belongs to category M21 (other acquired deformities of limbs), block M20-M25 (other joint disorders) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

Within M21, choose M21.6 (Other acquired deformities of foot) only when documentation doesn't support a more specific option: valgus deformity, not elsewhere classified (M21.0), varus deformity, not elsewhere classified (M21.1), flexion deformity (M21.2), wrist or foot drop (acquired) (M21.3), Flat foot [pes planus] (acquired) (M21.4), acquired clawhand, clubhand, clawfoot and clubfoot (M21.5), unequal limb length (acquired) (M21.7), other specified acquired deformities of limbs (M21.8) and 1 more.

To report this condition, pick the subcode that matches the documentation: M21.61 (Bunion), M21.62 (bunionette) and M21.6X (foot).

The conditions in its Excludes2 note aren't part of M21.6, but may be coded alongside it if the patient has both: deformities of toe (acquired) (M20.1-M20.6-).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.