Is M21 a billable code?
No. M21 is a header code that groups 124 more specific codes. Use one of the billable codes listed on this page instead.
ICD-10-CM FY2027 diagnosis code
M21: Other acquired deformities of limbs
Header code: not billableValid for dates of service October 1, 2026 to September 30, 2027
M21 groups related diagnoses under other acquired deformities of limbs. It cannot be used on a claim by itself. Choose the billable code below that matches the patient's record.
Billable codes under M21
- M21.00Valgus deformity, not elsewhere classified, unspecified site
- M21.021Valgus deformity, not elsewhere classified, right elbow
- M21.022Valgus deformity, not elsewhere classified, left elbow
- M21.029Valgus deformity, not elsewhere classified, unspecified elbow
- M21.051Valgus deformity, not elsewhere classified, right hip
- M21.052Valgus deformity, not elsewhere classified, left hip
- M21.059Valgus deformity, not elsewhere classified, unspecified hip
- M21.061Valgus deformity, not elsewhere classified, right knee
- M21.062Valgus deformity, not elsewhere classified, left knee
- M21.069Valgus deformity, not elsewhere classified, unspecified knee
- M21.071Valgus deformity, not elsewhere classified, right ankle
- M21.072Valgus deformity, not elsewhere classified, left ankle
- M21.079Valgus deformity, not elsewhere classified, unspecified ankle
- M21.10Varus deformity, not elsewhere classified, unspecified site
- M21.121Varus deformity, not elsewhere classified, right elbow
- M21.122Varus deformity, not elsewhere classified, left elbow
- M21.129Varus deformity, not elsewhere classified, unspecified elbow
- M21.151Varus deformity, not elsewhere classified, right hip
- M21.152Varus deformity, not elsewhere classified, left hip
- M21.159Varus deformity, not elsewhere classified, unspecified hip
- M21.161Varus deformity, not elsewhere classified, right knee
- M21.162Varus deformity, not elsewhere classified, left knee
- M21.169Varus deformity, not elsewhere classified, unspecified knee
- M21.171Varus deformity, not elsewhere classified, right ankle
- M21.172Varus deformity, not elsewhere classified, left ankle
- M21.179Varus deformity, not elsewhere classified, unspecified ankle
- M21.20Flexion deformity, unspecified site
- M21.211Flexion deformity, right shoulder
- M21.212Flexion deformity, left shoulder
- M21.219Flexion deformity, unspecified shoulder
- M21.221Flexion deformity, right elbow
- M21.222Flexion deformity, left elbow
- M21.229Flexion deformity, unspecified elbow
- M21.231Flexion deformity, right wrist
- M21.232Flexion deformity, left wrist
- M21.239Flexion deformity, unspecified wrist
- M21.241Flexion deformity, right finger joints
- M21.242Flexion deformity, left finger joints
- M21.249Flexion deformity, unspecified finger joints
- M21.251Flexion deformity, right hip
- M21.252Flexion deformity, left hip
- M21.259Flexion deformity, unspecified hip
- M21.261Flexion deformity, right knee
- M21.262Flexion deformity, left knee
- M21.269Flexion deformity, unspecified knee
- M21.271Flexion deformity, right ankle and toes
- M21.272Flexion deformity, left ankle and toes
- M21.279Flexion deformity, unspecified ankle and toes
- M21.331Wrist drop, right wrist
- M21.332Wrist drop, left wrist
- M21.339Wrist drop, unspecified wrist
- M21.371Foot drop, right foot
- M21.372Foot drop, left foot
- M21.379Foot drop, unspecified foot
- M21.40Flat foot [pes planus] (acquired), unspecified foot
- M21.41Flat foot [pes planus] (acquired), right foot
- M21.42Flat foot [pes planus] (acquired), left foot
- M21.511Acquired clawhand, right hand
- M21.512Acquired clawhand, left hand
- M21.519Acquired clawhand, unspecified hand
- M21.521Acquired clubhand, right hand
- M21.522Acquired clubhand, left hand
- M21.529Acquired clubhand, unspecified hand
- M21.531Acquired clawfoot, right foot
- M21.532Acquired clawfoot, left foot
- M21.539Acquired clawfoot, unspecified foot
- M21.541Acquired clubfoot, right foot
- M21.542Acquired clubfoot, left foot
- M21.549Acquired clubfoot, unspecified foot
- M21.611Bunion of right foot
- M21.612Bunion of left foot
- M21.619Bunion of unspecified foot
- M21.621Bunionette of right foot
- M21.622Bunionette of left foot
- M21.629Bunionette of unspecified foot
- M21.6X1Other acquired deformities of right foot
- M21.6X2Other acquired deformities of left foot
- M21.6X9Other acquired deformities of unspecified foot
- M21.70Unequal limb length (acquired), unspecified site
- M21.721Unequal limb length (acquired), right humerus
- M21.722Unequal limb length (acquired), left humerus
- M21.729Unequal limb length (acquired), unspecified humerus
- M21.731Unequal limb length (acquired), right ulna
- M21.732Unequal limb length (acquired), left ulna
- M21.733Unequal limb length (acquired), right radius
- M21.734Unequal limb length (acquired), left radius
- M21.739Unequal limb length (acquired), unspecified ulna and radius
- M21.751Unequal limb length (acquired), right femur
- M21.752Unequal limb length (acquired), left femur
- M21.759Unequal limb length (acquired), unspecified femur
- M21.761Unequal limb length (acquired), right tibia
- M21.762Unequal limb length (acquired), left tibia
- M21.763Unequal limb length (acquired), right fibula
- M21.764Unequal limb length (acquired), left fibula
- M21.769Unequal limb length (acquired), unspecified tibia and fibula
- M21.80Other specified acquired deformities of unspecified limb
- M21.821Other specified acquired deformities of right upper arm
- M21.822Other specified acquired deformities of left upper arm
- M21.829Other specified acquired deformities of unspecified upper arm
- M21.831Other specified acquired deformities of right forearm
- M21.832Other specified acquired deformities of left forearm
- M21.839Other specified acquired deformities of unspecified forearm
- M21.851Other specified acquired deformities of right thigh
- M21.852Other specified acquired deformities of left thigh
- M21.859Other specified acquired deformities of unspecified thigh
- M21.861Other specified acquired deformities of right lower leg
- M21.862Other specified acquired deformities of left lower leg
- M21.869Other specified acquired deformities of unspecified lower leg
- M21.90Unspecified acquired deformity of unspecified limb
- M21.921Unspecified acquired deformity of right upper arm
- M21.922Unspecified acquired deformity of left upper arm
- M21.929Unspecified acquired deformity of unspecified upper arm
- M21.931Unspecified acquired deformity of right forearm
- M21.932Unspecified acquired deformity of left forearm
- M21.939Unspecified acquired deformity of unspecified forearm
- M21.941Unspecified acquired deformity of hand, right hand
- M21.942Unspecified acquired deformity of hand, left hand
- M21.949Unspecified acquired deformity of hand, unspecified hand
- M21.951Unspecified acquired deformity of right thigh
- M21.952Unspecified acquired deformity of left thigh
- M21.959Unspecified acquired deformity of unspecified thigh
- M21.961Unspecified acquired deformity of right lower leg
- M21.962Unspecified acquired deformity of left lower leg
- M21.969Unspecified acquired deformity of unspecified lower leg
M21 questions
What does M21 mean?
M21 is the ICD-10-CM code for Other acquired deformities of limbs. It is in chapter 13, Diseases of the musculoskeletal system and connective tissue (M00-M99).
Code titles come from the official ICD-10-CM files published by the CDC National Center for Health Statistics. Always check payer rules and the clinical record before billing.