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S83.105S vs T84.023

S83.105S (Unspecified dislocation of left knee, sequela) compared with T84.023 (Instability of internal left knee prosthesis), from the official CMS tabular data.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Summary

These codes can be reported together when both conditions are documented, because S83.105S lists T84.023 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named and billing status.S83.105S is “Unspecified dislocation of left knee, sequela”; T84.023 is “Instability of internal left knee prosthesis”. T84.023 is a non-billable header; S83.105S is billable.

Registry fact

Can these codes be reported together?

Yes, when both are documented.S83.105S lists T84.023 under Excludes2: “instability of knee prosthesis (T84.022, T84.023)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

Yes.S83.105S’s tabular entry: “instability of knee prosthesis (T84.022, T84.023)”. The note covers T84.023.

Official ruleGuide: Excludes1 vs Excludes2

Is one a parent or header code?

One is a header.T84.023 is a non-billable header, but S83.105S is not one of its subdivisions.

Registry fact

Nothing found in 3 other checks; 1 check does not apply
Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code.

Official rule

Is one more specific?

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

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

S83.105S
Unspecified dislocation of left knee, sequela
↔
T84.023
Instability of internal left knee prosthesis

What we found

Yes, when both are documented.S83.105S carries an Excludes2 note covering T84.023: “instability of knee prosthesis (T84.022, T84.023)”

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 FY2027

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

Similar descriptions do not make codes interchangeable. The documentation and the official instructions decide which code applies.

Official descriptionDiffers
S83.105S

Unspecified dislocation of left knee, sequela

T84.023

Instability of internal left knee prosthesis

StatusDiffers
S83.105S
Billable
T84.023
Non-billable header

A header is not reported on a claim; a code beneath it is.

Report instead: T84.023A, T84.023D, T84.023S

Excludes2Differs
S83.105S
  • instability of knee prosthesis (T84.022, T84.023)
  • 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)
T84.023
  • failure and rejection of transplanted organs and tissues (T86.-)
  • fracture of bone following insertion of orthopedic implant, joint prosthesis or bone plate (M96.6)
  • any encounters with medical care for postprocedural conditions in which no complications are present, such as:
  • artificial opening status (Z93.-)
  • closure of external stoma (Z43.-)
  • fitting and adjustment of external prosthetic device (Z44.-)
  • burns and corrosions from local applications and irradiation (T20-T32)
  • complications of surgical procedures during pregnancy, childbirth and the puerperium (O00-O9A)
  • mechanical complication of respirator [ventilator] (J95.850)
  • poisoning and toxic effects of drugs and chemicals (T36-T65 with fifth or sixth character 1-4 or 6)
  • postprocedural fever (R50.82)
  • specified complications classified elsewhere, such as:
  • cerebrospinal fluid leak from spinal puncture (G97.0)
  • colostomy malfunction (K94.0-)
  • disorders of fluid and electrolyte imbalance (E86-E87)
  • functional disturbances following cardiac surgery (I97.0-I97.1)
  • intraoperative and postprocedural complications of specified body systems (D78.-, E36.-, E89.-, G97.3-, G97.4, H59.3-, H59.-, H95.2-, H95.3, I97.4-, I97.5, J95.6-, J95.7, K91.6-, L76.-, M96.-, N99.-)
  • ostomy complications (J95.0-, K94.-, N99.5-)
  • postgastric surgery syndromes (K91.1)
  • postlaminectomy syndrome NEC (M96.1)
  • postmastectomy lymphedema syndrome (I97.2)
  • postsurgical blind-loop syndrome (K91.2)
  • ventilator associated pneumonia (J95.851)
Use additional codeDiffers
S83.105S

None at this code

T84.023
  • code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
  • code(s) to identify the specified condition resulting from the complication
  • code to identify devices involved and details of circumstances (Y62-Y82)
Code alsoDiffers
S83.105S
  • any associated open wound
T84.023

None at this code

CategoryDiffers
S83.105S

S83 Dislocation and sprain of joints and ligaments of knee

T84.023

T84 Complications of internal orthopedic prosthetic devices, implants and grafts

ChapterSame for both

S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)

IncludesDiffers
S83.105S
  • 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
  • traumatic rupture of joint or ligament of knee
  • traumatic subluxation of joint or ligament of knee
  • traumatic tear of joint or ligament of knee
T84.023

None at this code

7th characterDiffers
S83.105S
  • The appropriate 7th character is to be added to each code from category S83
T84.023
  • The appropriate 7th character is to be added to each code from category T84

No Excludes1 and Code first note at either code.

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. In a row that differs, each code’s own notes are listed under it, and the notes every code shares are listed once beneath them.

Edit this comparisonCheck a whole claim

Derived from the official CMS ICD-10-CM tabular data (FY2027). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources