2027 ICD-10-CM Diagnosis Code M89.121Complete physeal arrest, right proximal humerus

ICD-10-CM Codes›M00–M99›M86-M90›M89

ICD-10-CM M89.121
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

M89.121 is a billable ICD-10-CM diagnosis code for complete physeal arrest, right proximal humerus. 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 Other specified bone disease and musculoskeletal deformities.

Code Identity

ICD-10-CM Code
M89.121
Billable Status
Yes — Valid for Submission
Code Describes
Complete physeal arrest, right proximal humerus
Short Description
Complete physeal arrest, right proximal humerus
Same as the full description in the CMS dataset.
Parent Code
M89.12
Physeal arrest, humerus

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM86-M90Other osteopathies
CategoryM89Other disorders of bone
This CodeM89.121Complete physeal arrest, right proximal humerus

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to M89.121: its own notes plus those printed at block M86-M90 and Chapter 13. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Block M86-M90 Other osteopathies applies to 732 codes
  • postprocedural osteopathies (M96.-)

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.

From Chapter 13 (M00-M99) Diseases of the musculoskeletal system and connective tissue applies to 6,687 codes
  • 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.

From Chapter 13 (M00-M99) Diseases of the musculoskeletal system and connective tissue applies to 6,687 codes
  • 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.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MUS028
Other specified bone disease and musculoskeletal deformities
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Bone Diseases

Your bones help you move, give you shape and support your body. They are living tissues that rebuild constantly throughout your life. During childhood and your teens, your body adds new bone faster than it removes old bone. After about age 20, you can lose bone faster than you make bone.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert M89.121 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
733.91 Arrest of bone growth
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About M89.121Overview

What is the ICD-10 code for complete physeal arrest, right proximal humerus?

The ICD-10-CM code for complete physeal arrest, right proximal humerus is M89.121 (sometimes written as M89121). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is M89.121 (Physeal arrest, humerus) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report complete physeal arrest, right proximal humerus on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does M89.121 group to?

When complete physeal arrest, right proximal humerus 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 M89.121 be reported with a code from M96?

Not as a rule. The Excludes1 note at block M86-M90, which applies to M89.121, lists "postprocedural osteopathies (M96.-)". 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 M89.121?

Under the General Equivalence Mappings, complete physeal arrest, right proximal humerus converts to ICD-9-CM 733.91 (arrest of bone growth). The mapping is approximate, so confirm the match fits the documentation.