2026 ICD-10-CM Diagnosis Code M86.662Other chronic osteomyelitis, left tibia and fibula

ICD-10-CM Codes›M00–M99›M86-M90›M86

ICD-10-CM M86.662
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M86.662 is a billable ICD-10-CM diagnosis code for other chronic osteomyelitis, left tibia and fibula. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 485 through 487, 539 through 541. Coders also document this condition as chronic osteomyelitis of left lower leg. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Osteomyelitis.

Code Identity

ICD-10-CM Code
M86.662
Billable Status
Yes — Valid for Submission
Code Describes
Other chronic osteomyelitis, left tibia and fibula
Short Description
Other chronic osteomyelitis, left tibia and fibula
Same as the full description in the CMS dataset.
Parent Code
M86.66
Other chronic osteomyelitis, tibia and fibula

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM86-M90Other osteopathies
CategoryM86Osteomyelitis
This CodeM86.662Other chronic osteomyelitis, left tibia and fibula

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Chronic osteomyelitis of left lower leg
  • Chronic osteomyelitis of left tibia
  • Chronic osteomyelitis of lower leg
  • Chronic osteomyelitis of tibia
  • Osteomyelitis of left tibia

Clinical ClassificationClinical

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

CCSR MUS002
Osteomyelitis
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Bone Infections

Like other parts of the body, bones can get infected. The infections are usually bacterial, but can also be fungal. They may spread to the bone from nearby skin or muscles, or from another part of the body through the bloodstream.

Read the full article at MedlinePlus

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

Convert M86.662 to ICD-9-CMHistory

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

ICD-9-CM
730.16 Chr osteomyelit-l/leg
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 M86.662Overview

Is M86.662 (Other chronic osteomyelitis, tibia and fibula) a billable code?

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

What MS-DRG does M86.662 group to?

When other chronic osteomyelitis, left tibia and fibula is the principal diagnosis on an inpatient stay, it groups to MS-DRG 485, 486, 487, 539, 540, 541, with relative weights from 0.7715 to 3.2271 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M86.662?

Under the General Equivalence Mappings, other chronic osteomyelitis, left tibia and fibula converts to ICD-9-CM 730.16 (chr osteomyelit-l/leg). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.