M23.0 ICD-10-CM Code: Cystic meniscus

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for M23.0 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on M23.0 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for M23.0

MedCoder structured workflow — derived from this code’s own official record

Before you code M23.0

1. M23.0 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).

   ReviewM23.00, M23.01, M23.02, M23.03, M23.04, M23.05, M23.06

   See the relationships section · Guide: How to choose an ICD-10-CM code →

2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with M23.0. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

   See the official tabular notes

Choose the right path

1. Does the documentation support one of the more specific codes beneath M23.0?
   Yes → Select that code and continue the checks below on its own page.
   No → M23.0 cannot be reported as written; query for the specificity its subcategory needs.

   ReviewM23.00, M23.01, M23.02, M23.03, M23.04, M23.05, M23.06

2. Does the documentation support a condition named in M23.0’s Excludes1 note?
   Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
   No → Continue.

   ReviewM24.66, M21, M93.2

Consider M23.0. Then confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement

Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

Official instructions as workflow

• Excludes1 — check before selecting M23.0(3 notes)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with M23.0: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

  CompareM24.66, M21, M93.2

  See the official tabular notes · Guidelines I.A.12.a

• Excludes2 — not part of M23.0(4 notes)

  Coding workflow: The conditions named in this note are not included in M23.0. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

  CompareM24.4

  See the official tabular notes · Guidelines I.A.12.b

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Don’t confuse M23.0 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of M23.0 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• M24.66— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of ankylosis moves the case to M24.66; the two are not reported together unless documented as unrelated.

  Full comparison: M23.0 vs M24.66 →

• M21— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of deformity of knee moves the case to M21; the two are not reported together unless documented as unrelated.

  Full comparison: M23.0 vs M21 →

• M93.2— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of osteochondritis dissecans moves the case to M93.2; the two are not reported together unless documented as unrelated.

  Full comparison: M23.0 vs M93.2 →

• S80— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of current injury - see injury of knee and lower leg adds S80; it is not part of this code and both may be reported when both are documented.

  Full comparison: M23.0 vs S80 →

• S89— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of current injury - see injury of knee and lower leg adds S89; it is not part of this code and both may be reported when both are documented.

  Full comparison: M23.0 vs S89 →

• M24.4— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of recurrent dislocation or subluxation of joints adds M24.4; it is not part of this code and both may be reported when both are documented.

  Full comparison: M23.0 vs M24.4 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

• Not billable as written — a more specific code is required: M23.000, M23.001, M23.002, M23.003, M23.004.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name M23.0 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 3 Excludes2 notes across 2 chapters: M24.1 — Other articular cartilage disorders (via M23.-), M24.2 — Disorder of ligament (via M23.-), S83 — Dislocation and sprain of joints and ligaments of knee (via M23.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Related Codes

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Derangement”; these codes share that main term but sit in a different category of the Tabular List.

M24.10 — Other articular cartilage disorders, unspecified site (joint, articular cartilage), M24.11 — Other articular cartilage disorders, shoulder (joint, articular cartilage, shoulder), M24.12 — Other articular cartilage disorders, elbow (joint, articular cartilage, elbow), M24.13 — Other articular cartilage disorders, wrist (joint, articular cartilage, wrist), M24.14 — Other articular cartilage disorders, hand (joint, articular cartilage, hand), M24.15 — Other articular cartilage disorders, hip (joint, articular cartilage, hip), M24.17 — Other articular cartilage disorders, ankle and foot (joint, articular cartilage, foot), M24.19 — Other articular cartilage disorders, other specified site (joint, articular cartilage, specified site NEC), M24.80 — Other specific joint derangements of unspecified joint, not elsewhere classified (joint, specified type NEC), M24.81 — Other specific joint derangements of shoulder, not elsewhere classified (joint, specified type NEC, shoulder), M24.82 — Other specific joint derangements of elbow, not elsewhere classified (joint, specified type NEC, elbow), M24.83 — Other specific joint derangements of wrist, not elsewhere classified (joint, specified type NEC, wrist), M24.84 — Other specific joint derangements of hand, not elsewhere classified (joint, specified type NEC, hand joint), M24.85 — Other specific joint derangements of hip, not elsewhere classified (joint, specified type NEC, hip), M24.87 — Other specific joint derangements of ankle and foot, not elsewhere classified (joint, specified type NEC, ankle), M24.89 — Other specific joint derangement of other specified joint, not elsewhere classified (joint, specified type NEC, specified site NEC), M24.9 — Joint derangement, unspecified (joint), M26.69 — Other specified disorders of temporomandibular joint (joint, temporomandibular)

Contextual Map

Every relationship of M23.0 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run M23.0 with these 3 related codes in Claim Check

Hierarchy

• M00-M99 — Chapter 13: Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) (M00-M99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00-M25 — Arthropathies[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M20-M25 — Other joint disorders[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes2 notes

• M24.1 — Other articular cartilage disorders[Excludes2](via M23.-): “internal derangement of knee (M23.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• M24.2 — Disorder of ligament[Excludes2](via M23.-): “internal derangement of knee (M23.5-M23.8X9)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S83 — Dislocation and sprain of joints and ligaments of knee[Excludes2](via M23.-): “internal derangement of knee (M23.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Nearest codes (40)

• M23 — Internal derangement of knee[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M23.00 — Cystic meniscus, unspecified meniscus[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M23.000 — Cystic meniscus, unspecified lateral meniscus, right knee[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M23.001 — Cystic meniscus, unspecified lateral meniscus, left knee[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M23.002 — Cystic meniscus, unspecified lateral meniscus, unspecified knee[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M23.003 — Cystic meniscus, unspecified medial meniscus, right knee[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M23.004 — Cystic meniscus, unspecified medial meniscus, left knee[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M23.005 — Cystic meniscus, unspecified medial meniscus, unspecified knee[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 32 more

Change history

• FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Common coding questions

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to M23.0 in its code family, with their registry titles.

• M23 — Internal derangement of knee
• M23.00 — Cystic meniscus, unspecified meniscus
• 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

View all codes in the M23 family