2021 ICD-10-CM Diagnosis Code M21.7

Unequal limb length (acquired)

    2016 2017 2018 2019 2020 2021 Non-Billable/Non-Specific Code
  • M21.7 should not be used for reimbursement purposes as there are multiple codes below it that contain a greater level of detail.
  • The 2021 edition of ICD-10-CM M21.7 became effective on October 1, 2020.
  • This is the American ICD-10-CM version of M21.7 - other international versions of ICD-10 M21.7 may differ.
  • The site used should correspond to the shorter limb
The following code(s) above M21.7 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 M21.7:
  • M00-M99
    2021 ICD-10-CM Range M00-M99

    Diseases of the musculoskeletal system and connective tissue

    • 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
Clinical Information
  • A disorder characterized by of a discrepancy between the lengths of the lower or upper extremities.
  • Discrepancy between the lengths of the lower or upper extremities.
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 M21.7
M21.612 …… of left foot
M21.619 …… of unspecified foot
M21.62 Bunionette
M21.621 …… of right foot
M21.622 …… of left foot
M21.629 …… of unspecified foot
M21.6X Other acquired deformities of foot
M21.6X1 Other acquired deformities of right foot
M21.6X2 Other acquired deformities of left foot
M21.6X9 Other acquired deformities of unspecified foot
M21.7 Unequal limb length (acquired)
M21.70 …… unspecified site
M21.72 Unequal limb length (acquired), humerus
M21.721 Unequal limb length (acquired), right humerus
M21.722 Unequal limb length (acquired), left humerus
M21.729 Unequal limb length (acquired), unspecified humerus
M21.73 Unequal limb length (acquired), ulna and radius
M21.731 Unequal limb length (acquired), right ulna
M21.732 Unequal limb length (acquired), left ulna
M21.733 Unequal limb length (acquired), right radius
M21.734 Unequal limb length (acquired), left radius

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