2026 ICD-10-CM Diagnosis Code M00.869Arthritis due to other bacteria, unspecified knee

ICD-10-CM Codes›M00–M99›M00-M02›M00

ICD-10-CM M00.869
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M00.869 is a billable ICD-10-CM diagnosis code for arthritis due to other bacteria, unspecified knee. 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, 548 through 550. The code is flagged as an unspecified code, since codes identifying laterality exist in the same family. Coders also document this condition as bacterial arthritis of patellofemoral joint. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Infective arthritis.

Code Identity

ICD-10-CM Code
M00.869
Billable Status
Yes — Valid for Submission
Code Describes
Arthritis due to other bacteria, unspecified knee
Short Description
Arthritis due to other bacteria, unspecified knee
Same as the full description in the CMS dataset.
Parent Code
M00.86
Arthritis due to other bacteria, knee

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM00-M02Infectious arthropathies
CategoryM00Pyogenic arthritis
This CodeM00.869Arthritis due to other bacteria, unspecified knee

Code EditsBilling

Medicare Code Editor checks that affect claim validity for M00.869.

Unspecified codes
Unspecified codes exist in the ICD-10-CM classification for circumstances when documentation in the medical record does not provide the level of detail needed to support reporting a more specific code. However, in the inpatient setting, there should generally be very limited and rare circumstances for which the laterality (right, left, bilateral) of a condition is unable to be documented and reported. The following pages contain the list of unspecified ICD-10-CM diagnosis codes for which there is a more specific code to identify laterality (right, left, bilateral) within that code family.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bacterial arthritis of patellofemoral joint
  • Infection of patella
  • Knee pyogenic arthritis
  • Pyogenic bacterial arthritis of knee
  • Pyogenic bacterial arthritis of patella
  • Sesamoiditis
  • Suppurative arthritis caused by bacteria

Clinical ClassificationClinical

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

CCSR INF003
Bacterial infections
Default principal diagnosis: inpatient No · outpatient No
CCSR MUS001
Infective arthritis
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Infectious Arthritis

Most kinds of arthritis cause pain and swelling in your joints. Joints are places where two bones meet, such as your elbow or knee. Infectious arthritis is an infection in the joint. The infection comes from a bacterial, viral, or fungal infection that spreads from another part of the body. Symptoms of infectious arthritis include:

Read the full article at MedlinePlus

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

Convert M00.869 to ICD-9-CMHistory

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

ICD-9-CM
711.06 Pyogen arthritis-l/leg
Approximate The match is approximate rather than exact.
ICD-9-CM
711.06 Pyogen arthritis-l/leg
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
041.89 Oth specf bacteria
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

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 M00.869Overview

Is M00.869 (Arthritis due to other bacteria, knee) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report arthritis due to other bacteria, unspecified knee on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M00.869 group to?

When arthritis due to other bacteria, unspecified knee is the principal diagnosis on an inpatient stay, it groups to MS-DRG 485, 486, 487, 548, 549, 550, with relative weights from 0.8741 to 3.2271 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M00.869?

Under the General Equivalence Mappings, arthritis due to other bacteria, unspecified knee converts to ICD-9-CM 711.06 (pyogen arthritis-l/leg), 711.06 (pyogen arthritis-l/leg), and 041.89 (oth specf bacteria). 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.