2026 ICD-10-CM Diagnosis Code M00.261Other streptococcal arthritis, right knee

ICD-10-CM Codes›M00–M99›M00-M02›M00

ICD-10-CM M00.261
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M00.261 is a billable ICD-10-CM diagnosis code for other streptococcal arthritis, right 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Infective arthritis.

Code Identity

ICD-10-CM Code
M00.261
Billable Status
Yes — Valid for Submission
Code Describes
Other streptococcal arthritis, right knee
Short Description
Other streptococcal arthritis, right knee
Same as the full description in the CMS dataset.
Parent Code
M00.26
Other streptococcal arthritis, knee

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM00-M02Infectious arthropathies
CategoryM00Pyogenic arthritis
This CodeM00.261Other streptococcal arthritis, right knee

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Arthritis of bilateral knee joints caused by bacteria
  • Arthritis of left knee caused by bacteria
  • Arthritis of right knee caused by bacteria
  • Bilateral infective arthritis of knees
  • Streptococcal arthritis of bilateral knees
  • Streptococcal arthritis of knee
  • Streptococcal arthritis of left knee
  • Streptococcal arthritis of right knee

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 M00.261 to ICD-9-CMHistory

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

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
041.09 Other streptococcus
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 M00.261Overview

Is M00.261 (Other streptococcal arthritis, knee) a billable code?

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

What MS-DRG does M00.261 group to?

When other streptococcal arthritis, right 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 M00.261?

Under the General Equivalence Mappings, other streptococcal arthritis, right knee converts to ICD-9-CM 711.06 (pyogen arthritis-l/leg) and 041.09 (other streptococcus). 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.