ICD-10-CM Tabular Index · Chapter 13 · FY 2026 M23

Internal derangement of knee (M23) ICD-10-CM

The M23 code range covers internal derangement of knee with 148 ICD-10-CM diagnosis codes. 111 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.

✓ Built from the official CMS FY 2026 datasetEffective Oct 1, 2025 – Sep 30, 2026
148
Diagnosis Codes
111
Billable Codes
M23
Code Range
M20–M25
Parent Section

Type 1 Excludes

A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.

Type 2 Excludes

A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

ICD-10-CM

Codes in the M23 Range 148 codes · 111 billable

148 of 148 shown
  • M23 Internal derangement of kneeNon-billable
  • M23.0 Cystic meniscusNon-billable
  • M23.00 Cystic meniscus, unspecified meniscusNon-billable
  • M23.000 Cystic meniscus, unspecified lateral meniscus, right knee
  • M23.001 Cystic meniscus, unspecified lateral meniscus, left knee
  • M23.002 Cystic meniscus, unspecified lateral meniscus, unspecified knee
  • M23.003 Cystic meniscus, unspecified medial meniscus, right knee
  • M23.004 Cystic meniscus, unspecified medial meniscus, left knee
  • M23.005 Cystic meniscus, unspecified medial meniscus, unspecified knee
  • M23.006 Cystic meniscus, unspecified meniscus, right knee
  • M23.007 Cystic meniscus, unspecified meniscus, left knee
  • M23.009 Cystic meniscus, unspecified meniscus, unspecified knee
  • M23.01 Cystic meniscus, anterior horn of medial meniscusNon-billable
  • M23.011 Cystic meniscus, anterior horn of medial meniscus, right knee
  • M23.012 Cystic meniscus, anterior horn of medial meniscus, left knee
  • M23.019 Cystic meniscus, anterior horn of medial meniscus, unspecified knee
  • M23.02 Cystic meniscus, posterior horn of medial meniscusNon-billable
  • M23.021 Cystic meniscus, posterior horn of medial meniscus, right knee
  • M23.022 Cystic meniscus, posterior horn of medial meniscus, left knee
  • M23.029 Cystic meniscus, posterior horn of medial meniscus, unspecified knee
  • M23.03 Cystic meniscus, other medial meniscusNon-billable
  • M23.031 Cystic meniscus, other medial meniscus, right knee
  • M23.032 Cystic meniscus, other medial meniscus, left knee
  • M23.039 Cystic meniscus, other medial meniscus, unspecified knee
  • M23.04 Cystic meniscus, anterior horn of lateral meniscusNon-billable
  • M23.041 Cystic meniscus, anterior horn of lateral meniscus, right knee
  • M23.042 Cystic meniscus, anterior horn of lateral meniscus, left knee
  • M23.049 Cystic meniscus, anterior horn of lateral meniscus, unspecified knee
  • M23.05 Cystic meniscus, posterior horn of lateral meniscusNon-billable
  • M23.051 Cystic meniscus, posterior horn of lateral meniscus, right knee
  • M23.052 Cystic meniscus, posterior horn of lateral meniscus, left knee
  • M23.059 Cystic meniscus, posterior horn of lateral meniscus, unspecified knee
  • M23.06 Cystic meniscus, other lateral meniscusNon-billable
  • M23.061 Cystic meniscus, other lateral meniscus, right knee
  • M23.062 Cystic meniscus, other lateral meniscus, left knee
  • M23.069 Cystic meniscus, other lateral meniscus, unspecified knee
  • M23.2 Derangement of meniscus due to old tear or injuryNon-billable
  • M23.20 Derangement of unspecified meniscus due to old tear or injuryNon-billable
  • M23.200 Derangement of unspecified lateral meniscus due to old tear or injury, right knee
  • M23.201 Derangement of unspecified lateral meniscus due to old tear or injury, left knee
  • M23.202 Derangement of unspecified lateral meniscus due to old tear or injury, unspecified knee
  • M23.203 Derangement of unspecified medial meniscus due to old tear or injury, right knee
  • M23.204 Derangement of unspecified medial meniscus due to old tear or injury, left knee
  • M23.205 Derangement of unspecified medial meniscus due to old tear or injury, unspecified knee
  • M23.206 Derangement of unspecified meniscus due to old tear or injury, right knee
  • M23.207 Derangement of unspecified meniscus due to old tear or injury, left knee
  • M23.209 Derangement of unspecified meniscus due to old tear or injury, unspecified knee
  • M23.21 Derangement of anterior horn of medial meniscus due to old tear or injuryNon-billable
  • M23.211 Derangement of anterior horn of medial meniscus due to old tear or injury, right knee
  • M23.212 Derangement of anterior horn of medial meniscus due to old tear or injury, left knee
  • M23.219 Derangement of anterior horn of medial meniscus due to old tear or injury, unspecified knee
  • M23.22 Derangement of posterior horn of medial meniscus due to old tear or injuryNon-billable
  • M23.221 Derangement of posterior horn of medial meniscus due to old tear or injury, right knee
  • M23.222 Derangement of posterior horn of medial meniscus due to old tear or injury, left knee
  • M23.229 Derangement of posterior horn of medial meniscus due to old tear or injury, unspecified knee
  • M23.23 Derangement of other medial meniscus due to old tear or injuryNon-billable
  • M23.231 Derangement of other medial meniscus due to old tear or injury, right knee
  • M23.232 Derangement of other medial meniscus due to old tear or injury, left knee
  • M23.239 Derangement of other medial meniscus due to old tear or injury, unspecified knee
  • M23.24 Derangement of anterior horn of lateral meniscus due to old tear or injuryNon-billable
  • M23.241 Derangement of anterior horn of lateral meniscus due to old tear or injury, right knee
  • M23.242 Derangement of anterior horn of lateral meniscus due to old tear or injury, left knee
  • M23.249 Derangement of anterior horn of lateral meniscus due to old tear or injury, unspecified knee
  • M23.25 Derangement of posterior horn of lateral meniscus due to old tear or injuryNon-billable
  • M23.251 Derangement of posterior horn of lateral meniscus due to old tear or injury, right knee
  • M23.252 Derangement of posterior horn of lateral meniscus due to old tear or injury, left knee
  • M23.259 Derangement of posterior horn of lateral meniscus due to old tear or injury, unspecified knee
  • M23.26 Derangement of other lateral meniscus due to old tear or injuryNon-billable
  • M23.261 Derangement of other lateral meniscus due to old tear or injury, right knee
  • M23.262 Derangement of other lateral meniscus due to old tear or injury, left knee
  • M23.269 Derangement of other lateral meniscus due to old tear or injury, unspecified knee
  • M23.3 Other meniscus derangementsNon-billable
  • M23.30 Other meniscus derangements, unspecified meniscusNon-billable
  • M23.300 Other meniscus derangements, unspecified lateral meniscus, right knee
  • M23.301 Other meniscus derangements, unspecified lateral meniscus, left knee
  • M23.302 Other meniscus derangements, unspecified lateral meniscus, unspecified knee
  • M23.303 Other meniscus derangements, unspecified medial meniscus, right knee
  • M23.304 Other meniscus derangements, unspecified medial meniscus, left knee
  • M23.305 Other meniscus derangements, unspecified medial meniscus, unspecified knee
  • M23.306 Other meniscus derangements, unspecified meniscus, right knee
  • M23.307 Other meniscus derangements, unspecified meniscus, left knee
  • M23.309 Other meniscus derangements, unspecified meniscus, unspecified knee
  • M23.31 Other meniscus derangements, anterior horn of medial meniscusNon-billable
  • M23.311 Other meniscus derangements, anterior horn of medial meniscus, right knee
  • M23.312 Other meniscus derangements, anterior horn of medial meniscus, left knee
  • M23.319 Other meniscus derangements, anterior horn of medial meniscus, unspecified knee
  • M23.32 Other meniscus derangements, posterior horn of medial meniscusNon-billable
  • M23.321 Other meniscus derangements, posterior horn of medial meniscus, right knee
  • M23.322 Other meniscus derangements, posterior horn of medial meniscus, left knee
  • M23.329 Other meniscus derangements, posterior horn of medial meniscus, unspecified knee
  • M23.33 Other meniscus derangements, other medial meniscusNon-billable
  • M23.331 Other meniscus derangements, other medial meniscus, right knee
  • M23.332 Other meniscus derangements, other medial meniscus, left knee
  • M23.339 Other meniscus derangements, other medial meniscus, unspecified knee
  • M23.34 Other meniscus derangements, anterior horn of lateral meniscusNon-billable
  • M23.341 Other meniscus derangements, anterior horn of lateral meniscus, right knee
  • M23.342 Other meniscus derangements, anterior horn of lateral meniscus, left knee
  • M23.349 Other meniscus derangements, anterior horn of lateral meniscus, unspecified knee
  • M23.35 Other meniscus derangements, posterior horn of lateral meniscusNon-billable
  • M23.351 Other meniscus derangements, posterior horn of lateral meniscus, right knee
  • M23.352 Other meniscus derangements, posterior horn of lateral meniscus, left knee
  • M23.359 Other meniscus derangements, posterior horn of lateral meniscus, unspecified knee
  • M23.36 Other meniscus derangements, other lateral meniscusNon-billable
  • M23.361 Other meniscus derangements, other lateral meniscus, right knee
  • M23.362 Other meniscus derangements, other lateral meniscus, left knee
  • M23.369 Other meniscus derangements, other lateral meniscus, unspecified knee
  • M23.4 Loose body in kneeNon-billable
  • M23.40 Loose body in knee, unspecified knee
  • M23.41 Loose body in knee, right knee
  • M23.42 Loose body in knee, left knee
  • M23.5 Chronic instability of kneeNon-billable
  • M23.50 Chronic instability of knee, unspecified knee
  • M23.51 Chronic instability of knee, right knee
  • M23.52 Chronic instability of knee, left knee
  • M23.6 Other spontaneous disruption of ligament(s) of kneeNon-billable
  • M23.60 Other spontaneous disruption of unspecified ligament of kneeNon-billable
  • M23.601 Other spontaneous disruption of unspecified ligament of right knee
  • M23.602 Other spontaneous disruption of unspecified ligament of left knee
  • M23.609 Other spontaneous disruption of unspecified ligament of unspecified knee
  • M23.61 Other spontaneous disruption of anterior cruciate ligament of kneeNon-billable
  • M23.611 Other spontaneous disruption of anterior cruciate ligament of right knee
  • M23.612 Other spontaneous disruption of anterior cruciate ligament of left knee
  • M23.619 Other spontaneous disruption of anterior cruciate ligament of unspecified knee
  • M23.62 Other spontaneous disruption of posterior cruciate ligament of kneeNon-billable
  • M23.621 Other spontaneous disruption of posterior cruciate ligament of right knee
  • M23.622 Other spontaneous disruption of posterior cruciate ligament of left knee
  • M23.629 Other spontaneous disruption of posterior cruciate ligament of unspecified knee
  • M23.63 Other spontaneous disruption of medial collateral ligament of kneeNon-billable
  • M23.631 Other spontaneous disruption of medial collateral ligament of right knee
  • M23.632 Other spontaneous disruption of medial collateral ligament of left knee
  • M23.639 Other spontaneous disruption of medial collateral ligament of unspecified knee
  • M23.64 Other spontaneous disruption of lateral collateral ligament of kneeNon-billable
  • M23.641 Other spontaneous disruption of lateral collateral ligament of right knee
  • M23.642 Other spontaneous disruption of lateral collateral ligament of left knee
  • M23.649 Other spontaneous disruption of lateral collateral ligament of unspecified knee
  • M23.67 Other spontaneous disruption of capsular ligament of kneeNon-billable
  • M23.671 Other spontaneous disruption of capsular ligament of right knee
  • M23.672 Other spontaneous disruption of capsular ligament of left knee
  • M23.679 Other spontaneous disruption of capsular ligament of unspecified knee
  • M23.8 Other internal derangements of kneeNon-billable
  • M23.8X Other internal derangements of kneeNon-billable
  • M23.8X1 Other internal derangements of right knee
  • M23.8X2 Other internal derangements of left knee
  • M23.8X9 Other internal derangements of unspecified knee
  • M23.9 Unspecified internal derangement of kneeNon-billable
  • M23.90 Unspecified internal derangement of unspecified knee
  • M23.91 Unspecified internal derangement of right knee
  • M23.92 Unspecified internal derangement of left knee

About the M23 Code Range

The ICD-10 code section M23 covers internal derangement of the knee, which includes various conditions affecting the knee's meniscus and ligaments, such as cysts, tears, loose bodies, and chronic instability. These codes provide precise classification for different types of knee joint disorders involving structural damage or dysfunction.

This section details a range of specific diagnoses like M23.0 for cystic meniscus conditions, with subcodes distinguishing between lateral and medial meniscus cysts, and their locations (right or left knee). It also includes codes such as M23.2 for meniscus derangement due to old tears or injuries, with terms like "bucket handle tear" linked to these codes. For example, the chronic instability of the knee (code M23.5) covers long-standing ligament disruptions, including anterior and posterior cruciate ligaments, which might be referred to by synonyms like "old disruption of ligament of knee." Other codes address spontaneous ligament ruptures and loose bodies within the knee joint. Medical coders can use these distinct codes for accurate documentation of knee injuries and degenerative changes, helping care providers capture detailed knee pathology under the ICD-10 framework.

Questions About This Page

How many billable codes are in the M23 range?

Of the 148 codes in this range, 111 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.

What does the M23 range classify?

The range classifies internal derangement of knee. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.

Related References

All ICD-10-CM ChaptersAll of Chapter 13ICD-10-CM Code LookupMS-DRG ReferenceMedicare Code EditsPOA Exempt Codes

Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.