2027 ICD-10-CM Diagnosis Code M21.6X9Other acquired deformities of unspecified foot
ICD-10-CM Codes›M00–M99›M20-M25›M21
- Billable — Valid for Submission
- Not Chronic
M21.6X9 is a billable ICD-10-CM diagnosis code for other acquired deformities of unspecified foot. 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 foot deformities.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Abduction deformity of foot
- Absent bone in foot
- Acquired abduction deformity of foot
- Acquired adduction deformity of foot
- Acquired cavovarus deformity of foot
- Acquired cavus deformity of foot
- Acquired dorsiflexed first ray
- Acquired dorsiflexed forefoot
- Acquired dorsiflexion deformity of foot
- Acquired equinus deformity of foot
- Acquired forefoot abductus
- Acquired forefoot adductus
- Acquired hallux valgus due to metatarsus primus varus
- Acquired metatarsus adductus
- Acquired metatarsus primus varus
- Acquired plantar-flexed fifth ray
- Acquired plantar-flexed first ray
- Acquired plantar-flexed forefoot
- Adductus deformity of foot
- Angulation of bone in foot
- Bowing of foot bone
- Calcaneovalgus deformity of foot
- Cavovarus deformity of foot
- Correction of low arch on tiptoe
- Defect of articular cartilage
- Deformity of bone in foot
- Deformity of metatarsal
- Dorsiflexion deformity of foot
- Finding of movement of foot
- Forefoot adductus
- Loss of protective sensation of skin
- Loss of protective sensation of skin of foot
- Osteochondral defect of talus
- Peripheral vascular disease of foot with loss of protective sensation and deformity
- Plantar flexion deformity of midtarsal joint
- Plantarflexion deformity of foot
- Postural calcaneovalgus
- Pronated forefoot
- Pronation deformity of the foot
- Pronation of foot
- Shortening of bone in foot
- Supination deformity of foot
- Supination deformity of forefoot
- Talar tilt
- Toeing-out
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to M21.6X9: its own notes plus those printed at M21.6, 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 M21.6X9, its category, or a range that includes it.
Excludes1 1
These codes carry an Excludes1 note naming M21.6X9: 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.
Patient EducationClinical
Foot Injuries and Disorders
Each of your feet has 26 bones, 33 joints, and more than 100 tendons, muscles, and ligaments. No wonder a lot of things can go wrong. Here are a few common problems:
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M21.6X9 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M21.6X9Overview
What is the ICD-10 code for other acquired deformities of unspecified foot?
The ICD-10-CM code for other acquired deformities of unspecified foot is M21.6X9 (sometimes written as M216X9). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is M21.6X9 (Other acquired deformities of foot) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report other acquired deformities of unspecified foot on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does M21.6X9 group to?
When other acquired deformities of unspecified foot 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 M21.6X9 be reported with a code from Z89?
Not as a rule. The Excludes1 note at M21, which applies to M21.6X9, 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 M21.6X9?
Under the General Equivalence Mappings, other acquired deformities of unspecified foot converts to ICD-9-CM 736.79 (acq ankle-foot def NEC). The mapping is approximate, so confirm the match fits the documentation.
