M21.10 Varus deformity, not elsewhere classified, unspecified site

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 M21.1 Varus deformity, not elsewhere classified

Excludes1 (never code together)

• metatarsus varus (Q66.22-)
• tibia vara (M92.51-)

MS-DRG index

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

Approximate ICD-9-CM (GEMs)

• 736.9 Acquired deformity of limb, site unspecified (approximate)

Code annotations containing back-references to M21.10

Back-references to M21.1

• Type 1 Excludes: Q66 Congenital deformities of feet ("varus deformities (acquired) (M21.1-)")

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)")

Diagnosis Index entries for M21.10

• Deformity › varus NEC

Nearby codes

• M21.07 Valgus deformity, not elsewhere classified, ankle
• M21.071 Valgus deformity, not elsewhere classified, right ankle
• M21.072 Valgus deformity, not elsewhere classified, left ankle
• M21.079 Valgus deformity, not elsewhere classified, unspecified ankle
• M21.1 Varus deformity, not elsewhere classified
• M21.10 Varus deformity, not elsewhere classified, unspecified site (this code)
• M21.12 Varus deformity, not elsewhere classified, elbow
• M21.121 Varus deformity, not elsewhere classified, right elbow
• M21.122 Varus deformity, not elsewhere classified, left elbow
• M21.129 Varus deformity, not elsewhere classified, unspecified elbow
• M21.15 Varus deformity, not elsewhere classified, hip