2021 ICD-10-CM Diagnosis Code M21.961

Unspecified acquired deformity of right lower leg

    2016 2017 2018 2019 2020 2021 Billable/Specific Code
  • M21.961 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
  • The 2021 edition of ICD-10-CM M21.961 became effective on October 1, 2020.
  • This is the American ICD-10-CM version of M21.961 - other international versions of ICD-10 M21.961 may differ.
The following code(s) above M21.961 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to M21.961:
  • M00-M99
    2021 ICD-10-CM Range M00-M99

    Diseases of the musculoskeletal system and connective tissue

    Note
    • Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition
    Type 2 Excludes
    • arthropathic psoriasis (L40.5-)
    • certain conditions originating in the perinatal period (P04-P96)
    • certain infectious and parasitic diseases (A00-B99)
    • compartment syndrome (traumatic) (T79.A-)
    • complications of pregnancy, childbirth and the puerperium (O00-O9A)
    • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
    • endocrine, nutritional and metabolic diseases (E00-E88)
    • injury, poisoning and certain other consequences of external causes (S00-T88)
    • neoplasms (C00-D49)
    • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
    Diseases of the musculoskeletal system and connective tissue
  • M20-M25
    2021 ICD-10-CM Range M20-M25

    Other joint disorders

    Type 2 Excludes
    Other joint disorders
  • M21
    ICD-10-CM Diagnosis Code M21

    Other acquired deformities of limbs

      2016 2017 2018 2019 2020 2021 Non-Billable/Non-Specific Code
    Type 1 Excludes
    • acquired absence of limb (Z89.-)
    • congenital absence of limbs (Q71-Q73)
    • congenital deformities and malformations of limbs (Q65-Q66, Q68-Q74)
    Type 2 Excludes
    • acquired deformities of fingers or toes (M20.-)
    • coxa plana (M91.2)
    Other acquired deformities of limbs
Approximate Synonyms
  • Acquired deformity of bilateral ankles
  • Acquired deformity of bilateral feet
  • Acquired deformity of bilateral knees
  • Acquired deformity of bilateral lower legs
  • Acquired deformity of right ankle
  • Acquired deformity of right foot
  • Acquired deformity of right knee
  • Acquired deformity of right lower leg
  • Deformity of bilateral feet due to rheumatoid arthritis
  • Deformity of right foot due to rheumatoid arthritis
  • Equinus deformity of bilateral feet
  • Equinus deformity of right foot
  • Plantarflexion deformity of bilateral feet
  • Plantarflexion deformity of right foot
  • Rheumatoid deformity of bilateral feet
  • Rheumatoid deformity of right foot
ICD-10-CM M21.961 is grouped within Diagnostic Related Group(s) (MS-DRG v38.0):
  • 564 Other musculoskeletal system and connective tissue diagnoses with mcc
  • 565 Other musculoskeletal system and connective tissue diagnoses with cc
  • 566 Other musculoskeletal system and connective tissue diagnoses without cc/mcc

Convert M21.961 to ICD-9-CM

Code History
  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
  • 2021 (effective 10/1/2020): No change
ICD-10-CM Codes Adjacent To M21.961
M21.939 Unspecified acquired deformity of unspecified forearm
M21.94 Unspecified acquired deformity of hand
M21.941 …… right hand
M21.942 …… left hand
M21.949 …… 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
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
M22 Disorder of patella
M22.0 Recurrent dislocation of patella
M22.00 …… unspecified knee
M22.01 …… right knee
M22.02 …… left knee
M22.1 Recurrent subluxation of patella
M22.10 …… unspecified knee
M22.11 …… right knee

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.