M21.3Wrist or foot drop (acquired)

M21.3 is the ICD-10-CM diagnosis code for wrist or foot drop (acquired). 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 2 subcodes must be used instead.

Within M21 (other acquired deformities of limbs), M21.3 is specifically for wrist or foot drop (acquired). Related codes cover valgus deformity, not elsewhere classified (M21.0), varus deformity, not elsewhere classified (M21.1), flexion deformity (M21.2), Flat foot [pes planus] (acquired) (M21.4), acquired clawhand, clubhand, clawfoot and clubfoot (M21.5), other acquired deformities of foot (M21.6), 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: M21.33 ((acquired)) and M21.37 ((acquired)).

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