M21.7 – Unequal limb length (acquired)
ICD-10-CM 2027 diagnosis code · Other joint disorders
ICD-10-CM code
M21.7
- Code
M21.7(claims format:M217)- Description
- Unequal limb length (acquired)
- Billable
- No – use a more specific code below
- Valid for
- Dates of service October 1, 2026 – September 30, 2027 (FY2027)
- Chapter
- 13. Diseases of the musculoskeletal system and connective tissue (M00-M99)
- Block
- M20-M25 Other joint disorders
- Parent codes
- M21
Billable codes under M21.7
M21.7 is a header code and cannot be used on claims. Choose the most specific code:
- M21.70 – Unequal limb length (acquired), unspecified siteBillable
- M21.72 – Unequal limb length (acquired), humerusHeader (more codes below)
- M21.73 – Unequal limb length (acquired), ulna and radiusHeader (more codes below)
- M21.75 – Unequal limb length (acquired), femurHeader (more codes below)
- M21.76 – Unequal limb length (acquired), tibia and fibulaHeader (more codes below)
Notes for M21.7
Notes:
- The site used should correspond to the shorter limb
Notes inherited from parent codes
Instructional notes at a category or block level apply to every code below it.
M21 – Other acquired deformities of limbs
Excludes1 (not coded here):
Block M20-M25
Related codes in M21
- M21.0 – Valgus deformity, not elsewhere classifiedHeader
- M21.1 – Varus deformity, not elsewhere classifiedHeader
- M21.2 – Flexion deformityHeader
- M21.3 – Wrist or foot drop (acquired)Header
- M21.4 – Flat foot [pes planus] (acquired)Header
- M21.5 – Acquired clawhand, clubhand, clawfoot and clubfootHeader
- M21.6 – Other acquired deformities of footHeader
- M21.8 – Other specified acquired deformities of limbsHeader
- M21.9 – Unspecified acquired deformity of limb and handHeader
Frequently asked questions
What is ICD-10 code M21.7?
M21.7 is the ICD-10-CM code for unequal limb length (acquired), in the block M20-M25 (Other joint disorders).
Is M21.7 a billable code?
No. M21.7 is a header code with more specific child codes; report one of the billable codes listed above.
What category does M21.7 belong to?
It belongs to category M21 – Other acquired deformities of limbs.
Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.