ICDcodes.org
FY2027

M21.20 — Flexion deformity, unspecified site

BillableUnspecified

Is M21.20 billable?

Yes, but M21.20 is an unspecified code. M21.20 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, M21.20 is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting M21.20 — the more specific alternatives are listed below.

M21.20 at a glance

CodeM21.20
DescriptionFlexion deformity, unspecified site
BillableYes
Code setICD-10-CM FY2027
Valid for encountersOctober 1, 2026 – September 30, 2027

Which MS-DRGs does M21.20 group to?

M21.20 sits in MDC 08 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.

  • 564Other Musculoskeletal System and Connective Tissue Diagnoses with MCCmedical
  • 565Other Musculoskeletal System and Connective Tissue Diagnoses with CCmedical
  • 566Other Musculoskeletal System and Connective Tissue Diagnoses without CC/MCCmedical

How is M21.20 listed in the Alphabetic Index?

These are the routes through the Alphabetic Index that lead to M21.20. They show the wording a clinician may have documented, which often differs from the Tabular description.

  • Deformity › flexion
  • Flexion › deformity, joint
  • Deformity › limb › flexion

Excludes1 — never code together — inherited from M21

The conditions below can never be reported together with M21.20 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.

  • acquired absence of limb (Z89.-)
  • congenital absence of limbs (Q71-Q73)
  • congenital deformities and malformations of limbs (Q65-Q66, Q68-Q74)

Excludes2 — not included here — inherited from Chapter 13

The conditions below are not part of M21.20, but a patient may have both at the same time. When documentation supports it, M21.20 and the excluded code may both 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)

Excludes2 — not included here — inherited from M20-M25

The conditions below are not part of M21.20, but a patient may have both at the same time. When documentation supports it, M21.20 and the excluded code may both be reported.

  • joints of the spine (M40-M54)

Excludes2 — not included here — inherited from M21

The conditions below are not part of M21.20, but a patient may have both at the same time. When documentation supports it, M21.20 and the excluded code may both be reported.

  • acquired deformities of fingers or toes (M20.-)
  • coxa plana (M91.2)

How long has M21.20 existed?

M21.20 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.

Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.

Which conditions are coded to M21.20?

What other codes are in the M21.2 family? (7)