M21.279 Flexion deformity, unspecified ankle and toes

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)

MS-DRG index

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

Approximate ICD-9-CM (GEMs)

• 736.89 Other acquired deformity of other parts of limb (approximate)

Code annotations containing back-references to M21.279

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

• M21.262 Flexion deformity, left knee
• M21.269 Flexion deformity, unspecified knee
• M21.27 Flexion deformity, ankle and toes
• M21.271 Flexion deformity, right ankle and toes
• M21.272 Flexion deformity, left ankle and toes
• M21.279 Flexion deformity, unspecified ankle and toes (this code)
• M21.3 Wrist or foot drop (acquired)
• M21.33 Wrist drop (acquired)
• M21.331 Wrist drop, right wrist
• M21.332 Wrist drop, left wrist
• M21.339 Wrist drop, unspecified wrist