M21.764 Unequal limb length (acquired), left fibula

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 M21.7 Unequal limb length (acquired)

Notes

• The site used should correspond to the shorter limb

MS-DRG index

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

Approximate ICD-9-CM (GEMs)

• 736.81 Unequal leg length (acquired) (approximate)

Code annotations containing back-references to M21.764

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

• M21.759 Unequal limb length (acquired), unspecified femur
• M21.76 Unequal limb length (acquired), tibia and fibula
• M21.761 Unequal limb length (acquired), right tibia
• M21.762 Unequal limb length (acquired), left tibia
• M21.763 Unequal limb length (acquired), right fibula
• M21.764 Unequal limb length (acquired), left fibula (this code)
• M21.769 Unequal limb length (acquired), unspecified tibia and fibula
• M21.8 Other specified acquired deformities of limbs
• M21.80 Other specified acquired deformities of unspecified limb
• M21.82 Other specified acquired deformities of upper arm
• M21.821 Other specified acquired deformities of right upper arm