2026 ICD-10-CM Diagnosis Code M23.641Other spontaneous disruption of lateral collateral ligament of right knee

ICD-10-CM Codes›M00–M99›M20-M25›M23

ICD-10-CM M23.641
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M23.641 is a billable ICD-10-CM diagnosis code for other spontaneous disruption of lateral collateral ligament of right knee. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 562 through 563. Coders also document this condition as chronic rupture of lateral collateral ligament of bilateral knee joints. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified joint disorders.

Code Identity

ICD-10-CM Code
M23.641
Billable Status
Yes — Valid for Submission
Code Describes
Other spontaneous disruption of lateral collateral ligament of right knee
Short Description
Oth spon disruption of lateral collat ligament of right knee
Parent Code
M23.64
Other spontaneous disruption of lateral collateral ligament of knee

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM20-M25Other joint disorders
CategoryM23Internal derangement of knee
This CodeM23.641Other spontaneous disruption of lateral collateral ligament of right knee

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Chronic rupture of lateral collateral ligament of bilateral knee joints
  • Chronic rupture of lateral collateral ligament of knee joint
  • Chronic rupture of lateral collateral ligament of left knee
  • Chronic rupture of lateral collateral ligament of right knee
  • Rupture of lateral collateral ligament of knee

Clinical ClassificationClinical

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

CCSR MUS007
Other specified joint disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Knee Injuries and Disorders

Your knee joint is made up of bone, cartilage, ligaments and fluid. Muscles and tendons help the knee joint move. When any of these structures is hurt or diseased, you have knee problems. Knee problems can cause pain and difficulty walking.

Read the full article at MedlinePlus

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

Convert M23.641 to ICD-9-CMHistory

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

ICD-9-CM
717.89 Int derangement knee 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 M23.641Overview

Is M23.641 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other spontaneous disruption of lateral collateral ligament of right knee on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M23.641 group to?

When other spontaneous disruption of lateral collateral ligament of right knee is the principal diagnosis on an inpatient stay, it groups to MS-DRG 562, 563, with relative weights from 0.8955 to 1.4248 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M23.641?

Under the General Equivalence Mappings, other spontaneous disruption of lateral collateral ligament of right knee converts to ICD-9-CM 717.89 (int derangement knee 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.