ICD-10-CM Code M21

Other acquired deformities of limbs

Version 2020 Non-Billable Code

Not Valid for Submission

M21 is a "header" nonspecific and non-billable code code, consider using a code with a higher level of specificity for a diagnosis of other acquired deformities of limbs. The code is NOT valid for the year 2020 for the submission of HIPAA-covered transactions.

ICD-10:M21
Short Description:Other acquired deformities of limbs
Long Description:Other acquired deformities of limbs

Consider the following ICD-10 codes with a higher level of specificity:

  • M21.0 - Valgus deformity, not elsewhere classified
  • M21.00 - Valgus deformity, not elsewhere classified, unspecified site
  • M21.02 - Valgus deformity, not elsewhere classified, elbow
  • M21.021 - Valgus deformity, not elsewhere classified, right elbow
  • M21.022 - Valgus deformity, not elsewhere classified, left elbow
  • M21.029 - Valgus deformity, not elsewhere classified, unspecified elbow
  • M21.05 - Valgus deformity, not elsewhere classified, hip
  • M21.051 - Valgus deformity, not elsewhere classified, right hip
  • M21.052 - Valgus deformity, not elsewhere classified, left hip
  • M21.059 - Valgus deformity, not elsewhere classified, unspecified hip
  • M21.06 - Valgus deformity, not elsewhere classified, knee
  • M21.061 - Valgus deformity, not elsewhere classified, right knee
  • M21.062 - Valgus deformity, not elsewhere classified, left knee
  • M21.069 - Valgus deformity, not elsewhere classified, unspecified knee
  • 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
  • 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
  • M21.151 - Varus deformity, not elsewhere classified, right hip
  • M21.152 - Varus deformity, not elsewhere classified, left hip
  • M21.159 - Varus deformity, not elsewhere classified, unspecified
  • M21.16 - Varus deformity, not elsewhere classified, knee
  • M21.161 - Varus deformity, not elsewhere classified, right knee
  • M21.162 - Varus deformity, not elsewhere classified, left knee
  • M21.169 - Varus deformity, not elsewhere classified, unspecified knee
  • M21.17 - Varus deformity, not elsewhere classified, ankle
  • M21.171 - Varus deformity, not elsewhere classified, right ankle
  • M21.172 - Varus deformity, not elsewhere classified, left ankle
  • M21.179 - Varus deformity, not elsewhere classified, unspecified ankle
  • M21.2 - Flexion deformity
  • M21.20 - Flexion deformity, unspecified site
  • M21.21 - Flexion deformity, shoulder
  • M21.211 - Flexion deformity, right shoulder
  • M21.212 - Flexion deformity, left shoulder
  • M21.219 - Flexion deformity, unspecified shoulder
  • M21.22 - Flexion deformity, elbow
  • M21.221 - Flexion deformity, right elbow
  • M21.222 - Flexion deformity, left elbow
  • M21.229 - Flexion deformity, unspecified elbow
  • M21.23 - Flexion deformity, wrist
  • M21.231 - Flexion deformity, right wrist
  • M21.232 - Flexion deformity, left wrist
  • M21.239 - Flexion deformity, unspecified wrist
  • M21.24 - Flexion deformity, finger joints
  • M21.241 - Flexion deformity, right finger joints
  • M21.242 - Flexion deformity, left finger joints
  • M21.249 - Flexion deformity, unspecified finger joints
  • M21.25 - Flexion deformity, hip
  • M21.251 - Flexion deformity, right hip
  • M21.252 - Flexion deformity, left hip
  • M21.259 - Flexion deformity, unspecified hip
  • M21.26 - Flexion deformity, knee
  • M21.261 - Flexion deformity, right knee
  • M21.262 - Flexion deformity, left knee
  • M21.269 - Flexion deformity, unspecified knee
  • M21.27 - Flexion deformity, ankle and toes
  • M21.271 - Flexion deformity, right ankle and toes
  • M21.272 - Flexion deformity, left ankle and toes
  • M21.279 - Flexion deformity, unspecified ankle and toes
  • M21.3 - Wrist or foot drop (acquired)
  • M21.33 - Wrist drop (acquired)
  • M21.331 - Wrist drop, right wrist
  • M21.332 - Wrist drop, left wrist
  • M21.339 - Wrist drop, unspecified wrist
  • M21.37 - Foot drop (acquired)
  • M21.371 - Foot drop, right foot
  • M21.372 - Foot drop, left foot
  • M21.379 - Foot drop, unspecified foot
  • M21.4 - Flat foot [pes planus] (acquired)
  • M21.40 - Flat foot [pes planus] (acquired), unspecified foot
  • M21.41 - Flat foot [pes planus] (acquired), right foot
  • M21.42 - Flat foot [pes planus] (acquired), left foot
  • M21.5 - Acquired clawhand, clubhand, clawfoot and clubfoot
  • M21.51 - Acquired clawhand
  • M21.511 - Acquired clawhand, right hand
  • M21.512 - Acquired clawhand, left hand
  • M21.519 - Acquired clawhand, unspecified hand
  • M21.52 - Acquired clubhand
  • M21.521 - Acquired clubhand, right hand
  • M21.522 - Acquired clubhand, left hand
  • M21.529 - Acquired clubhand, unspecified hand
  • M21.53 - Acquired clawfoot
  • M21.531 - Acquired clawfoot, right foot
  • M21.532 - Acquired clawfoot, left foot
  • M21.539 - Acquired clawfoot, unspecified foot
  • M21.54 - Acquired clubfoot
  • M21.541 - Acquired clubfoot, right foot
  • M21.542 - Acquired clubfoot, left foot
  • M21.549 - Acquired clubfoot, unspecified foot
  • M21.6 - Other acquired deformities of foot
  • M21.61 - Bunion
  • M21.611 - Bunion of right foot
  • M21.612 - Bunion of left foot
  • M21.619 - Bunion of unspecified foot
  • M21.62 - Bunionette
  • M21.621 - Bunionette of right foot
  • M21.622 - Bunionette of left foot
  • M21.629 - Bunionette 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 - Unequal limb length (acquired), 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
  • M21.739 - Unequal limb length (acquired), unspecified ulna and radius
  • M21.75 - Unequal limb length (acquired), femur
  • M21.751 - Unequal limb length (acquired), right femur
  • M21.752 - Unequal limb length (acquired), left femur
  • 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
  • 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
  • M21.822 - Other specified acquired deformities of left upper arm
  • M21.829 - Other specified acquired deformities of unspecified upper arm
  • M21.83 - Other specified acquired deformities of forearm
  • M21.831 - Other specified acquired deformities of right forearm
  • M21.832 - Other specified acquired deformities of left forearm
  • M21.839 - Other specified acquired deformities of unspecified forearm
  • M21.85 - Other specified acquired deformities of thigh
  • M21.851 - Other specified acquired deformities of right thigh
  • M21.852 - Other specified acquired deformities of left thigh
  • M21.859 - Other specified acquired deformities of unspecified thigh
  • M21.86 - Other specified acquired deformities of lower leg
  • M21.861 - Other specified acquired deformities of right lower leg
  • M21.862 - Other specified acquired deformities of left lower leg
  • M21.869 - Other specified acquired deformities of unspecified lower leg
  • M21.9 - Unspecified acquired deformity of limb and hand
  • M21.90 - Unspecified acquired deformity of unspecified limb
  • M21.92 - Unspecified acquired deformity of upper arm
  • M21.921 - Unspecified acquired deformity of right upper arm
  • M21.922 - Unspecified acquired deformity of left upper arm
  • M21.929 - Unspecified acquired deformity of unspecified upper arm
  • M21.93 - Unspecified acquired deformity of forearm
  • M21.931 - Unspecified acquired deformity of right forearm
  • M21.932 - Unspecified acquired deformity of left forearm
  • M21.939 - Unspecified acquired deformity of unspecified forearm
  • M21.94 - Unspecified acquired deformity of hand
  • M21.941 - Unspecified acquired deformity of hand, right hand
  • 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
  • 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

Tabular List of Diseases and Injuries

The Tabular List of Diseases and Injuries is a list of ICD-10 codes, organized "head to toe" into chapters and sections with guidance for inclusions, exclusions, descriptions and more. The following references are applicable to the code M21:

Type 1 Excludes

Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
  • acquired absence of limb Z89
  • congenital absence of limbs Q71 Q73
  • congenital deformities and malformations of limbs Q65 Q66 Q68 Q74

Type 2 Excludes

Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
  • acquired deformities of fingers or toes M20
  • coxa plana M91.2

Code Classification

  • Diseases of the musculoskeletal system and connective tissue (M00–M99)
    • Other joint disorders (M20-M25)
      • Other acquired deformities of limbs (M21)

Code History

  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016
    (First year ICD-10-CM implemented into the HIPAA code set)
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020

Information for Patients


Joint Disorders

A joint is where two or more bones come together, like the knee, hip, elbow, or shoulder. Joints can be damaged by many types of injuries or diseases, including

  • Arthritis - inflammation of a joint. It causes pain, stiffness, and swelling. Over time, the joint can become severely damaged.
  • Bursitis - inflammation of a fluid-filled sac that cushions the joint
  • Dislocations - injuries that force the ends of the bones out of position

Treatment of joint problems depends on the cause. If you have a sports injury, treatment often begins with the RICE (Rest, Ice, Compression, and Elevation) method to relieve pain, reduce swelling, and speed healing. Other possible treatments include pain relievers, keeping the injured area from moving, rehabilitation, and sometimes surgery. For arthritis, injuries, or other diseases, you may need joint replacement surgery to remove the damaged joint and put in a new one.

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases


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