Other acquired deformities of limbs (M21) ICD-10-CM
The M21 code range covers other acquired deformities of limbs with 172 ICD-10-CM diagnosis codes. 124 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
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
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.
Codes in the M21 Range 172 codes · 124 billable
- M21 Other acquired deformities of limbsNon-billable
- M21.0 Valgus deformity, not elsewhere classifiedNon-billable
- M21.00 Valgus deformity, not elsewhere classified, unspecified site
- M21.02 Valgus deformity, not elsewhere classified, elbowNon-billable
- 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, hipNon-billable
- 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, kneeNon-billable
- 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, ankleNon-billable
- 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 classifiedNon-billable
- M21.10 Varus deformity, not elsewhere classified, unspecified site
- M21.12 Varus deformity, not elsewhere classified, elbowNon-billable
- 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, hipNon-billable
- 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 hip
- M21.16 Varus deformity, not elsewhere classified, kneeNon-billable
- 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, ankleNon-billable
- 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 deformityNon-billable
- M21.20 Flexion deformity, unspecified site
- M21.21 Flexion deformity, shoulderNon-billable
- M21.211 Flexion deformity, right shoulder
- M21.212 Flexion deformity, left shoulder
- M21.219 Flexion deformity, unspecified shoulder
- M21.22 Flexion deformity, elbowNon-billable
- M21.221 Flexion deformity, right elbow
- M21.222 Flexion deformity, left elbow
- M21.229 Flexion deformity, unspecified elbow
- M21.23 Flexion deformity, wristNon-billable
- M21.231 Flexion deformity, right wrist
- M21.232 Flexion deformity, left wrist
- M21.239 Flexion deformity, unspecified wrist
- M21.24 Flexion deformity, finger jointsNon-billable
- 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, hipNon-billable
- M21.251 Flexion deformity, right hip
- M21.252 Flexion deformity, left hip
- M21.259 Flexion deformity, unspecified hip
- M21.26 Flexion deformity, kneeNon-billable
- M21.261 Flexion deformity, right knee
- M21.262 Flexion deformity, left knee
- M21.269 Flexion deformity, unspecified knee
- M21.27 Flexion deformity, ankle and toesNon-billable
- 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)Non-billable
- M21.33 Wrist drop (acquired)Non-billable
- M21.331 Wrist drop, right wrist
- M21.332 Wrist drop, left wrist
- M21.339 Wrist drop, unspecified wrist
- M21.37 Foot drop (acquired)Non-billable
- 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)Non-billable
- 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 clubfootNon-billable
- M21.51 Acquired clawhandNon-billable
- M21.511 Acquired clawhand, right hand
- M21.512 Acquired clawhand, left hand
- M21.519 Acquired clawhand, unspecified hand
- M21.52 Acquired clubhandNon-billable
- M21.521 Acquired clubhand, right hand
- M21.522 Acquired clubhand, left hand
- M21.529 Acquired clubhand, unspecified hand
- M21.53 Acquired clawfootNon-billable
- M21.531 Acquired clawfoot, right foot
- M21.532 Acquired clawfoot, left foot
- M21.539 Acquired clawfoot, unspecified foot
- M21.54 Acquired clubfootNon-billable
- M21.541 Acquired clubfoot, right foot
- M21.542 Acquired clubfoot, left foot
- M21.549 Acquired clubfoot, unspecified foot
- M21.6 Other acquired deformities of footNon-billable
- M21.61 BunionNon-billable
- M21.611 Bunion of right foot
- M21.612 Bunion of left foot
- M21.619 Bunion of unspecified foot
- M21.62 BunionetteNon-billable
- M21.621 Bunionette of right foot
- M21.622 Bunionette of left foot
- M21.629 Bunionette of unspecified foot
- M21.6X Other acquired deformities of footNon-billable
- 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)Non-billable
- M21.70 Unequal limb length (acquired), unspecified site
- M21.72 Unequal limb length (acquired), humerusNon-billable
- 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 radiusNon-billable
- 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), femurNon-billable
- 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 fibulaNon-billable
- 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 limbsNon-billable
- M21.80 Other specified acquired deformities of unspecified limb
- M21.82 Other specified acquired deformities of upper armNon-billable
- 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 forearmNon-billable
- 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 thighNon-billable
- 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 legNon-billable
- 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 handNon-billable
- M21.90 Unspecified acquired deformity of unspecified limb
- M21.92 Unspecified acquired deformity of upper armNon-billable
- 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 forearmNon-billable
- 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 handNon-billable
- 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 thighNon-billable
- 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 legNon-billable
- 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
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the M21 range.
Bunion
Abnormal swelling of the inner aspect of the first metatarsal head affecting the first METATARSOPHALANGEAL JOINT.
Bunion, Tailor's
Abnormal swelling of the outer aspect of the fifth metatarsal head affecting the fifth METATARSOPHALANGEAL JOINT.
Genu Valgum
An inward slant of the thigh in which the knees are close together and the ankles far apart. Genu valgum can develop due to skeletal and joint dysplasias (e.g., OSTEOARTHRITIS; HURLER SYNDROME); and malnutrition (e.g., RICKETS; FLUORIDE POISONING).
About the M21 Code Range
These are acquired changes in the shape of limbs and hands, including unequal limb length and changes to the feet.
The groups first separate deformities by type and affected joint: valgus (M21.0), varus (M21.1) and flexion (M21.2). Other groups distinguish wrist from foot drop (M21.3), flat foot by side (M21.4), and hand and foot deformities by type (M21.5, M21.6). Unequal limb length is divided by affected bone (M21.7). The remaining groups distinguish specified from unspecified deformities by limb region (M21.8, M21.9).
Questions About This Page
How many billable codes are in the M21 range?
Of the 172 codes in this range, 124 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the M21 range classify?
The range classifies other acquired deformities of limbs. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
