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M24.36 vs S83.51

M24.36 (Pathological dislocation of knee, not elsewhere classified) compared with S83.51 (Sprain of anterior cruciate ligament of knee), from the official CMS tabular data.

Summary

These codes can be reported together when both conditions are documented, because S83.51 lists M24.36 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named and chapter.M24.36 is “Pathological dislocation of knee, not elsewhere classified”; S83.51 is “Sprain of anterior cruciate ligament of knee”. M24.36 sits in M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99); S83.51 in S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88).

Registry fact

Can these codes be reported together?

Yes, when both are documented.S83.51 lists M24.36 under Excludes2: “old dislocation of knee (M24.36)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code. M24.36 carries 4 Excludes1 notes covering other codes; the side-by-side table quotes them.

Official rule

Is there an Excludes2 relationship?

Yes.S83.51’s tabular entry: “old dislocation of knee (M24.36)”. The note covers M24.36.

Official ruleGuide: Excludes1 vs Excludes2

Is one more specific?

Not comparable.The codes sit in different categories; specificity is only comparable within one category.

Is one a parent or header code?

Both are headers.Both are non-billable headers, and neither contains the other.

Registry fact

Are there sequencing instructions?

None.Neither entry carries a Code First or Use Additional Code note that names the other.

Official rule

Are there other coding relationships?

None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.

MedCoder-derived

Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels

Can these codes be reported together?

Informational

Excludes2 relationship

S83.51
Sprain of anterior cruciate ligament of knee
↔
M24.36
Pathological dislocation of knee, not elsewhere classified

What we found

Yes, when both are documented.S83.51 carries an Excludes2 note covering M24.36: “old dislocation of knee (M24.36)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

What to review

Report both only when the documentation supports both conditions; otherwise report the one documented.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.

Source / rule

CMS ICD-10-CM tabular instructional notes

Official guidance behind these answers

  • Section I.A.12.b — Excludes2 · applies to: Excludes2

    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 Official Guidelines FY2026

Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum

Side by side

M24.36Pathological dislocation of knee, not elsewhere classifiedS83.51Sprain of anterior cruciate ligament of knee
Billing statusNon-billable header

Report instead: M24.361, M24.362, M24.369

Non-billable header

Report instead: S83.511A, S83.511D, S83.511S, S83.512A, S83.512D

ClassificationM00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99)S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)
DefinitionPathological dislocation of knee, not elsewhere classified is a non-billable ICD-10-CM category code (M24.36).Sprain of anterior cruciate ligament of knee is a non-billable ICD-10-CM category code (S83.51).
7th character—The appropriate 7th character is to be added to each code from category S83
Includes—
avulsion of joint or ligament of knee
laceration of cartilage, joint or ligament of knee
sprain of cartilage, joint or ligament of knee
traumatic hemarthrosis of joint or ligament of knee
Excludes1
congenital dislocation or displacement of joint- see congenital malformations and deformations of the musculoskeletal system (Q65-Q79)
current injury - see injury of joints and ligaments by body region
recurrent dislocation of joint (M24.4-)
current injury - see injury of joint by body region
—
Excludes2
ganglion (M67.4)
snapping knee (M23.8-)
temporomandibular joint disorders (M26.6-)
joints of the spine (M40-M54)
derangement of patella (M22.0-M22.3)
injury of patellar ligament (tendon) (S76.1-)
internal derangement of knee (M23.-)
old dislocation of knee (M24.36)
pathological dislocation of knee (M24.36)
recurrent dislocation of knee (M22.0)
strain of muscle, fascia and tendon of lower leg (S86.-)
burns and corrosions (T20-T32)
frostbite (T33-T34)
injuries of ankle and foot, except fracture of ankle and malleolus (S90-S99)
insect bite or sting, venomous (T63.4)
Code also—
any associated open wound

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on.

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Derived from the official CMS ICD-10-CM tabular data (FY2026). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources