2027 ICD-10-CM Diagnosis Code M21.061Valgus deformity, not elsewhere classified, right knee
ICD-10-CM Codes›M00–M99›M20-M25›M21
- Billable — Valid for Submission
- Not Chronic
M21.061 is a billable ICD-10-CM diagnosis code for valgus deformity, not elsewhere classified, right knee. 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. Coders also document this condition as acquired deformity of left knee. 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 deformity of left knee
- Acquired deformity of right knee
- Acquired genu valgum
- Acquired genu valgum of bilateral knees
- Acquired valgus deformity of joint of lower limb
- Acquired valgus deformity of right knee
- Bilateral acquired deformity of knee regions
- Knee joint valgus deformity
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to M21.061: its own notes plus those printed at M21.0, 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 M21.061, its category, or a range that includes it.
Excludes1 2
These codes carry an Excludes1 note naming M21.061: they are not reported together with it, unless the two conditions are unrelated.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
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).
Patient EducationClinical
Knee Injuries and Disorders
Your knee joint is made up of bone, cartilage, ligaments and fluid. Muscles and tendons help the knee joint move. When any of these structures is hurt or diseased, you have knee problems. Knee problems can cause pain and difficulty walking.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M21.061 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M21.061Overview
What is the ICD-10 code for valgus deformity, not elsewhere classified, right knee?
The ICD-10-CM code for valgus deformity, not elsewhere classified, right knee is M21.061 (sometimes written as M21061). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is M21.061 (Valgus deformity, not elsewhere classified, knee) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report valgus deformity, not elsewhere classified, right knee on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does M21.061 group to?
When valgus deformity, not elsewhere classified, right knee 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 M21.061 be reported with Q66.6?
Not as a rule. The Excludes1 note at M21.0, which applies to M21.061, lists "metatarsus valgus (Q66.6)". 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 M21.061?
Under the General Equivalence Mappings, valgus deformity, not elsewhere classified, right knee converts to ICD-9-CM 736.41 (genu valgum). The mapping is approximate, so confirm the match fits the documentation.
