M21.959 Unspecified acquired deformity of unspecified thigh

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)

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

Code annotations containing back-references to M21.959

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

• M21.942 Unspecified acquired deformity of hand, left hand
• M21.949 Unspecified acquired deformity of hand, unspecified hand
• M21.95 Unspecified acquired deformity of thigh
• M21.951 Unspecified acquired deformity of right thigh
• M21.952 Unspecified acquired deformity of left thigh
• M21.959 Unspecified acquired deformity of unspecified thigh (this code)
• M21.96 Unspecified acquired deformity of lower leg
• M21.961 Unspecified acquired deformity of right lower leg
• M21.962 Unspecified acquired deformity of left lower leg
• M21.969 Unspecified acquired deformity of unspecified lower leg