M20.021 Boutonnière deformity of right finger(s)

Billable ICD-10-CM code, FY2026.

Applies from M20 Acquired deformities of fingers and toes

Excludes1 (never code together)

• acquired absence of fingers and toes (Z89.-)
• congenital absence of fingers and toes (Q71.3-, Q72.3-)
• congenital deformities and malformations of fingers and toes (Q66.-, Q68-Q70, Q74.-)

Applies from M20.0 Deformity of finger(s)

Excludes1 (never code together)

• clubbing of fingers (R68.3)
• palmar fascial fibromatosis [Dupuytren] (M72.0)
• trigger finger (M65.3)

MS-DRG index

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

Approximate ICD-9-CM (GEMs)

• 736.21 Boutonniere deformity (approximate)

Code annotations containing back-references to M20.021

Back-references to M20

• Type 2 Excludes: M21 Other acquired deformities of limbs ("acquired deformities of fingers or toes (M20.-)")
• 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

• M20.01 Mallet finger
• M20.011 Mallet finger of right finger(s)
• M20.012 Mallet finger of left finger(s)
• M20.019 Mallet finger of unspecified finger(s)
• M20.02 Boutonniere deformity
• M20.021 Boutonniere deformity of right finger(s) (this code)
• M20.022 Boutonniere deformity of left finger(s)
• M20.029 Boutonniere deformity of unspecified finger(s)
• M20.03 Swan-neck deformity
• M20.031 Swan-neck deformity of right finger(s)
• M20.032 Swan-neck deformity of left finger(s)