M21
Other acquired deformities of limbs
Not billable — category only FY2026 2025-10-01 → 2026-09-30
Exclusions 15 never code together
M21code
Excludes1
M00-M99chapter
Excludes2
- arthropathic psoriasis (L40.5-)L40.5-
- certain conditions originating in the perinatal period (P04-P96)P04-P96
- certain infectious and parasitic diseases (A00-B99)A00-B99
- compartment syndrome (traumatic) (T79.A-)T79.A-
- complications of pregnancy, childbirth and the puerperium (O00-O9A)O00-O9A
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Q00-Q99
- endocrine, nutritional and metabolic diseases (E00-E88)E00-E88
- injury, poisoning and certain other consequences of external causes (S00-T88)S00-T88
- neoplasms (C00-D49)C00-D49
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)R00-R94
Excludes1 — never code together. The excluded condition and this one are mutually exclusive.
Excludes2 — not included here, but the patient may have both. Code both when documented.
Instructional notes 2
Index entries leading here filed at null
No alphabetic index entry points at this code.
Subordinate codes 10
M21.0 Valgus deformity, not elsewhere classified M21.1 Varus deformity, not elsewhere classified M21.2 Flexion deformity M21.3 Wrist or foot drop (acquired) M21.4 Flat foot [pes planus] (acquired) M21.5 Acquired clawhand, clubhand, clawfoot and clubfoot M21.6 Other acquired deformities of foot M21.7 Unequal limb length (acquired) M21.8 Other specified acquired deformities of limbs M21.9 Unspecified acquired deformity of limb and hand
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.