Other acquired deformities of limbs (M21) ICD-10-CM

About the M21 Code Range

ICD-10 code section M21 covers other acquired deformities of limbs, specifying various types of deformities affecting arms, legs, wrists, ankles, feet, and hands that develop after birth rather than being congenital. These codes distinguish deformities such as valgus and varus angulation, flexion deformities, foot and wrist drop, and specific conditions like acquired clawhand or clubfoot.

This set includes detailed codes identifying deformities by location and laterality, for example, M21.061 for acquired valgus deformity of the right knee (often called "genu valgum" or "knock-knee") and M21.371 for foot drop, right foot. The synonyms listed help clarify terms that medical coders might encounter, such as "coxa valga" for valgus deformity of the hip (M21.051) or “Bunion” for specific acquired foot deformities (M21.611). Codes like M21.70 cover unequal limb length acquired from injury or disease, important for documenting shortening or length differences in arms or legs. Detailed classifications also address unspecified sites and bilateral conditions. Overall, this section enables precise coding for acquired limb deformities, supporting accurate clinical documentation and billing.