2026 ICD-10-CM Diagnosis Code M87.865Other osteonecrosis, left fibula

ICD-10-CM Codes›M00–M99›M86-M90›M87

ICD-10-CM M87.865
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M87.865 is a billable ICD-10-CM diagnosis code for other osteonecrosis, left fibula. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 553 through 554. Coders also document this condition as osteonecrosis of bilateral fibulas. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Aseptic necrosis and osteonecrosis.

Code Identity

ICD-10-CM Code
M87.865
Billable Status
Yes — Valid for Submission
Code Describes
Other osteonecrosis, left fibula
Short Description
Other osteonecrosis, left fibula
Same as the full description in the CMS dataset.
Parent Code
M87.86
Other osteonecrosis, tibia and fibula

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM86-M90Other osteopathies
CategoryM87Osteonecrosis
This CodeM87.865Other osteonecrosis, left fibula

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Osteonecrosis of bilateral fibulas
  • Osteonecrosis of fibula
  • Osteonecrosis of left fibula
  • Osteonecrosis of right fibula

Clinical ClassificationClinical

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

CCSR MUS030
Aseptic necrosis and osteonecrosis
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Osteonecrosis

Osteonecrosis is a disease caused by reduced blood flow to bones in the joints. In people with healthy bones, new bone is always replacing old bone. In osteonecrosis, the lack of blood causes the bone to break down faster than the body can make enough new bone. The bone starts to die and may break down.

Read the full article at MedlinePlus

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

Convert M87.865 to ICD-9-CMHistory

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

ICD-9-CM
733.49 Asept necrosis bone NEC
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 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About M87.865Overview

Is M87.865 (Other osteonecrosis, tibia and fibula) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other osteonecrosis, left fibula on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M87.865 group to?

When other osteonecrosis, left fibula is the principal diagnosis on an inpatient stay, it groups to MS-DRG 553, 554, with relative weights from 0.8301 to 1.2963 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M87.865?

Under the General Equivalence Mappings, other osteonecrosis, left fibula converts to ICD-9-CM 733.49 (asept necrosis bone NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.