ICD-10-CM 2027
ICD-10 code for limb acquired deformity
From the official ICD-10-CM alphabetic index entry “Deformity › limb (acquired)”. Page updated September 29, 2026.
About coding limb acquired deformity
The ICD-10-CM code for limb acquired deformity is M21.90 (Unspecified acquired deformity of unspecified limb). The official index lists 36 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on M21.90.
Within M21.9, choose M21.90 (unspecified limb) only when documentation doesn't support a more specific option: upper arm (M21.92), forearm (M21.93), hand (M21.94), thigh (M21.95) and lower leg (M21.96).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 564 (Other Musculoskeletal System and Connective Tissue Diagnoses with MCC, relative weight 1.4908), DRG 565 (Other Musculoskeletal System and Connective Tissue Diagnoses with CC, relative weight 0.9783) and DRG 566 (Other Musculoskeletal System and Connective Tissue Diagnoses without CC/MCC, relative weight 0.7378), in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific limb acquired deformity codes (official index)
- clawfoot M21.53 — Acquired clawfoot
- clawhand M21.51 — Acquired clawhand
- congenital Q68.1 — Congenital deformity of finger(s) and hand
- clubfoot M21.54 — Acquired clubfoot
- clubhand M21.52 — Acquired clubhand
- congenital, except reduction deformity Q74.9 — Unspecified congenital malformation of limb(s)
- flat foot M21.4 — Flat foot [pes planus] (acquired)
- flexion M21.20 — Flexion deformity, unspecified site
- ankle M21.27 — Flexion deformity, ankle and toes
- elbow M21.22 — Flexion deformity, elbow
- finger M21.24 — Flexion deformity, finger joints
- hip M21.25 — Flexion deformity, hip
- knee M21.26 — Flexion deformity, knee
- shoulder M21.21 — Flexion deformity, shoulder
- toe M21.27 — Flexion deformity, ankle and toes
- wrist M21.23 — Flexion deformity, wrist
- foot
- claw
- club
- drop M21.37 — Foot drop (acquired)
- flat
- specified NEC M21.6X — Other acquired deformities of foot
- forearm M21.93 — Unspecified acquired deformity of forearm
- hand M21.94 — Unspecified acquired deformity of hand
- lower leg M21.96 — Unspecified acquired deformity of lower leg
- specified type NEC M21.80 — Other specified acquired deformities of unspecified limb
- forearm M21.83 — Other specified acquired deformities of forearm
- lower leg M21.86 — Other specified acquired deformities of lower leg
- thigh M21.85 — Other specified acquired deformities of thigh
- upper arm M21.82 — Other specified acquired deformities of upper arm
- thigh M21.95 — Unspecified acquired deformity of thigh
- unequal length M21.70 — Unequal limb length (acquired), unspecified site
- short site is
- femur M21.75 — Unequal limb length (acquired), femur
- fibula M21.76 — Unequal limb length (acquired), tibia and fibula
- humerus M21.72 — Unequal limb length (acquired), humerus
- radius M21.73 — Unequal limb length (acquired), ulna and radius
- tibia M21.76 — Unequal limb length (acquired), tibia and fibula
- ulna M21.73 — Unequal limb length (acquired), ulna and radius
- upper arm M21.92 — Unspecified acquired deformity of upper arm
- valgus
- varus
- wrist drop M21.33 — Wrist drop (acquired)
Common questions about limb acquired deformity ICD-10 codes
What is the ICD-10 code for limb acquired deformity?
- M21.90 — Unspecified acquired deformity of unspecified limb. More specific codes apply when the documentation supports them: M21.53, M21.51, Q68.1, M21.54 and others below.
What is the ICD-10 code for clawfoot limb acquired deformity?
- M21.53 — Acquired clawfoot (header code; choose a more specific subcode).
What is the ICD-10 code for clawhand limb acquired deformity?
- M21.51 — Acquired clawhand (header code; choose a more specific subcode).
What is the ICD-10 code for clubfoot limb acquired deformity?
- M21.54 — Acquired clubfoot (header code; choose a more specific subcode).
What is the ICD-10 code for clubhand limb acquired deformity?
- M21.52 — Acquired clubhand (header code; choose a more specific subcode).
What is the ICD-10 code for flat foot limb acquired deformity?
- M21.4 — Flat foot [pes planus] (acquired) (header code; choose a more specific subcode).
What is the ICD-10 code for flexion limb acquired deformity?
- M21.20 — Flexion deformity, unspecified site.
Is M21.90 billable?
- Yes. M21.90 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can M21.90 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict M21.90 as a principal diagnosis.
Is M21.90 a CC or MCC?
- No. M21.90 is neither a CC nor an MCC under MS-DRG v44.0.