2027 ICD-10-CM Diagnosis Code M21.862Other specified acquired deformities of left lower leg
ICD-10-CM Codes›M00–M99›M20-M25›M21
- Billable — Valid for Submission
- Not Chronic
M21.862 is a billable ICD-10-CM diagnosis code for other specified acquired deformities of left lower leg. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 564 through 566. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Acquired deformities (excluding foot).
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acquired bilateral genu recurvatum
- Acquired deformity of left knee
- Acquired deformity of left lower leg
- Acquired deformity of right knee
- Acquired deformity of right lower leg
- Acquired genu recurvatum
- Acquired genu recurvatum of left knee
- Acquired genu recurvatum of right knee
- Acquired internal tibial torsion
- Acquired internal torsion of tibia of bilateral lower limbs
- Acquired internal torsion of tibia of left lower limb
- Acquired internal torsion of tibia of right lower limb
- Bilateral acquired deformity of knee regions
- Bilateral acquired deformity of lower legs
- Internal tibial torsion
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to M21.862: its own notes plus those printed at M21.8, M21, block M00-M25, block M20-M25, and Chapter 13. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- Disorders affecting predominantly peripheral (limb) joints
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- 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)
Notes
General instructions on how these codes are used.
- Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name M21.862, its category, or a range that includes it.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Leg Injuries and Disorders
Your legs are made up of bones, blood vessels, muscles, and other connective tissue. They are important for motion and standing. Playing sports, running, falling, or having an accident can damage your legs. Common leg injuries include sprains and strains, joint dislocations, and fractures (broken bones).
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M21.862 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M21.862Overview
What is the ICD-10 code for other specified acquired deformities of left lower leg?
The ICD-10-CM code for other specified acquired deformities of left lower leg is M21.862 (sometimes written as M21862). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is M21.862 (Other specified acquired deformities of lower leg) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report other specified acquired deformities of left lower leg on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does M21.862 group to?
When other specified acquired deformities of left lower leg is the principal diagnosis on an inpatient stay, it groups to MS-DRG 564, 566, 565, with relative weights from 0.7374 to 1.4909 depending on complications. Higher weights mean higher Medicare reimbursement.
Can M21.862 be reported with a code from Z89?
Not as a rule. The Excludes1 note at M21, which applies to M21.862, lists "acquired absence of limb (Z89.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
What is the ICD-9 equivalent of M21.862?
Under the General Equivalence Mappings, other specified acquired deformities of left lower leg converts to ICD-9-CM 736.6 (acq knee deformity NEC). The mapping is approximate, so confirm the match fits the documentation.
