2027 ICD-10-CM Diagnosis Code M23Internal derangement of knee

ICD-10-CM Codes›M00–M99›M20-M25›M23

ICD-10-CM M23
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

M23 is a non-billable ICD-10-CM category code for internal derangement of knee, so it cannot be submitted on claims. Use a more specific code from this category instead, such as M23.000, M23.001, M23.002, and M23.003.

Code Identity

ICD-10-CM Code
M23
Billable Status
No — Non-Billable Category
Code Describes
Internal derangement of knee
Short Description
Internal derangement of knee
Same as the full description in the CMS dataset.
Chapter
M20-M25
Other joint disorders

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM20-M25Other joint disorders
CategoryM23Internal derangement of knee
This CodeM23Internal derangement of knee

Specific Coding for Internal derangement of kneeOverview

Non-specific codes like M23 require more characters. Use one of these billable codes instead:

  • M23.0 for Cystic meniscus

  • M23.00 for Cystic meniscus, unspecified meniscus

  • M23.01 for Cystic meniscus, anterior horn of medial meniscus

  • M23.02 for Cystic meniscus, posterior horn of medial meniscus

  • M23.03 for Cystic meniscus, other medial meniscus

  • M23.04 for Cystic meniscus, anterior horn of lateral meniscus

  • M23.05 for Cystic meniscus, posterior horn of lateral meniscus

  • M23.06 for Cystic meniscus, other lateral meniscus

  • M23.2 for Derangement of meniscus due to old tear or injury

  • M23.20 for Derangement of unspecified meniscus due to old tear or injury

  • M23.21 for Derangement of anterior horn of medial meniscus due to old tear or injury

  • M23.22 for Derangement of posterior horn of medial meniscus due to old tear or injury

  • M23.23 for Derangement of other medial meniscus due to old tear or injury

  • M23.24 for Derangement of anterior horn of lateral meniscus due to old tear or injury

  • M23.25 for Derangement of posterior horn of lateral meniscus due to old tear or injury

  • M23.26 for Derangement of other lateral meniscus due to old tear or injury

  • M23.3 for Other meniscus derangements

  • M23.30 for Other meniscus derangements, unspecified meniscus

  • M23.31 for Other meniscus derangements, anterior horn of medial meniscus

  • M23.32 for Other meniscus derangements, posterior horn of medial meniscus

  • M23.33 for Other meniscus derangements, other medial meniscus

  • M23.34 for Other meniscus derangements, anterior horn of lateral meniscus

  • M23.35 for Other meniscus derangements, posterior horn of lateral meniscus

  • M23.36 for Other meniscus derangements, other lateral meniscus

  • M23.4 for Loose body in knee

  • Use M23.40 for Loose body in knee, unspecified knee

  • Use M23.41 for Loose body in knee, right knee

  • Use M23.42 for Loose body in knee, left knee

  • M23.5 for Chronic instability of knee

  • Use M23.50 for Chronic instability of knee, unspecified knee

  • Use M23.51 for Chronic instability of knee, right knee

  • Use M23.52 for Chronic instability of knee, left knee

  • M23.6 for Other spontaneous disruption of ligament(s) of knee

  • M23.60 for Other spontaneous disruption of unspecified ligament of knee

  • M23.61 for Other spontaneous disruption of anterior cruciate ligament of knee

  • M23.62 for Other spontaneous disruption of posterior cruciate ligament of knee

  • M23.63 for Other spontaneous disruption of medial collateral ligament of knee

  • M23.64 for Other spontaneous disruption of lateral collateral ligament of knee

  • M23.67 for Other spontaneous disruption of capsular ligament of knee

  • M23.8 for Other internal derangements of knee

  • M23.8X for Other internal derangements of knee

  • M23.9 for Unspecified internal derangement of knee

  • Use M23.90 for Unspecified internal derangement of unspecified knee

  • Use M23.91 for Unspecified internal derangement of right knee

  • Use M23.92 for Unspecified internal derangement of left knee

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to M23: its own notes plus those printed at block M00-M25, block M20-M25, and Chapter 13. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Block M00-M25 applies to 2,249 codes
  • Disorders affecting predominantly peripheral (limb) joints

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

On M23 itself
  • current injury - see injury of knee and lower leg (S80-S89)
  • recurrent dislocation or subluxation of joints (M24.4)
  • recurrent dislocation or subluxation of patella (M22.0-M22.1)
From Block M20-M25 Other joint disorders applies to 719 codes
From Chapter 13 (M00-M99) Diseases of the musculoskeletal system and connective tissue applies to 6,687 codes
  • arthropathic psoriasis (L40.5-)
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • compartment syndrome (traumatic) (T79.A-)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Notes

General instructions on how these codes are used.

From Chapter 13 (M00-M99) Diseases of the musculoskeletal system and connective tissue applies to 6,687 codes
  • Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name M23, its category, or a range that includes it.

Excludes2 2

These codes carry an Excludes2 note naming M23: its condition is not part of those codes, and both may be reported when the patient has both.

  • M24.1 Other articular cartilage disorders
    internal derangement of knee (M23.-)
  • S83 Dislocation and sprain of joints and ligaments of knee
    internal derangement of knee (M23.-)

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.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About M23Overview

What is the ICD-10 code for internal derangement of knee?

M23 is the ICD-10-CM category for internal derangement of knee, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is M23 (Internal derangement of knee) a billable code?

No. This is a category header that groups the codes for internal derangement of knee, and headers cannot be submitted on claims. Claims for internal derangement of knee need a more specific code from this category, such as M23.000, M23.001, and M23.002.

Can M23 be reported with M24.66?

Not as a rule. The Excludes1 note on M23 lists "ankylosis (M24.66)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).