M21.839 Other specified acquired deformities of unspecified forearm

Billable ICD-10-CM code, FY2026.

Applies from M21 Other acquired deformities of limbs

Excludes1 (never code together)

• acquired absence of limb (Z89.-)
• congenital absence of limbs (Q71-Q73)
• congenital deformities and malformations of limbs (Q65-Q66, Q68-Q74)

Excludes2 (not included here)

• acquired deformities of fingers or toes (M20.-)
• coxa plana (M91.2)

Applies from M21.8 Other specified acquired deformities of limbs

Excludes2 (not included here)

• coxa plana (M91.2)

MS-DRG index

Defines the logic of DRG(s) 564-566 in MDC 08.

Approximate ICD-9-CM (GEMs)

• 736.09 Other acquired deformities of forearm, excluding fingers (approximate)

Code annotations containing back-references to M21.839

Back-references to M21

• Type 1 Excludes: M23 Internal derangement of knee ("deformity of knee (M21.-)")
• Type 2 Excludes: M24.5 Contracture of joint ("acquired deformities of limbs (M20-M21)")
• Type 2 Excludes: M25 Other joint disorder, not elsewhere classified ("acquired deformities of limb (M20-M21)")
• Type 2 Excludes: M95 Other acquired deformities of musculoskeletal system and connective tissue ("acquired deformities of limbs (M20-M21)")
• Type 1 Excludes: Z89 Acquired absence of limb ("acquired deformities of limbs (M20-M21)")

Nearby codes

• M21.822 Other specified acquired deformities of left upper arm
• M21.829 Other specified acquired deformities of unspecified upper arm
• M21.83 Other specified acquired deformities of forearm
• M21.831 Other specified acquired deformities of right forearm
• M21.832 Other specified acquired deformities of left forearm
• M21.839 Other specified acquired deformities of unspecified forearm (this code)
• M21.85 Other specified acquired deformities of thigh
• M21.851 Other specified acquired deformities of right thigh
• M21.852 Other specified acquired deformities of left thigh
• M21.859 Other specified acquired deformities of unspecified thigh
• M21.86 Other specified acquired deformities of lower leg