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S82.64XN ICD-10-CM Code: Nondisplaced fracture of lateral malleolus of right fibula, subsequent encounter for open fracture type IIIA, IIIB, or IIIC with nonunion

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

7th character
Required — see the character table on this page
Tabular directives
1 inclusion term · 2 Excludes1 · 7 Excludes2

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

  • MS-DRG 564 — OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITH MCC (MDC 08)
  • MS-DRG 565 — OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITH CC (MDC 08)
  • MS-DRG 566 — OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITHOUT CC/MCC (MDC 08)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for S82.64XN in the official ICD-10-CM tabular list, quoted as published.

Notes without a marker are published on S82.64XN itself; “inherited from” names the category or block whose note applies here.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • fracture of malleolus

Source: inherited from S82

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

7th Character Guide

"The appropriate 7th character is to be added to all codes from category S82"

  • A — initial encounter for closed fracture
  • B — initial encounter for open fracture type I or II
  • C — initial encounter for open fracture type IIIA, IIIB, or IIIC
  • D — subsequent encounter for closed fracture with routine healing
  • E — subsequent encounter for open fracture type I or II with routine healing
  • F — subsequent encounter for open fracture type IIIA, IIIB, or IIIC with routine healing
  • G — subsequent encounter for closed fracture with delayed healing
  • H — subsequent encounter for open fracture type I or II with delayed healing
  • J — subsequent encounter for open fracture type IIIA, IIIB, or IIIC with delayed healing
  • K — subsequent encounter for closed fracture with nonunion
  • M — subsequent encounter for open fracture type I or II with nonunion
  • N — subsequent encounter for open fracture type IIIA, IIIB, or IIIC with nonunion (this page’s code)
  • P — subsequent encounter for closed fracture with malunion
  • Q — subsequent encounter for open fracture type I or II with malunion
  • R — subsequent encounter for open fracture type IIIA, IIIB, or IIIC with malunion
  • S — sequela

How the encounter character is assigned. “Initial encounter” means the patient is receiving active treatment for the condition — it is not limited to the first visit, and a different or new provider giving active treatment still assigns it. “Subsequent encounter” covers care during the healing or recovery phase after active treatment. “Sequela” is for complications or conditions that arise as a direct result of the original condition.

ICD-10-CM Official Guidelines for Coding and Reporting, Section I.C.19.a (paraphrased by MedCoder).

Variant codes in this family

S82.64XA, S82.64XB, S82.64XC, S82.64XD, S82.64XE, S82.64XF, S82.64XG, S82.64XH, S82.64XJ, S82.64XK, S82.64XM, S82.64XN, S82.64XP, S82.64XQ, S82.64XR, S82.64XS

Character meanings are CMS's official 7th-character extensions for this family, as carried in each variant code's official description; variant codes are registry rows. The explanation of how the encounter character is assigned is MedCoder editorial, distinct from the official content above it.

Code Overview

Nondisplaced fracture of lateral malleolus of right fibula, subsequent encounter for open fracture type IIIA, IIIB, or IIIC with nonunion is a billable ICD-10-CM diagnosis code (S82.64XN).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Official Coding Guidelines

Verbatim excerpts from the ICD-10-CM Official Guidelines for Coding and Reporting (CMS/NCHS) that govern this code.

Chapter 19: Injury, poisoning, and certain other consequences of external causes (S00-T88)

c. Coding of Traumatic Fractures The principles of multiple coding of injuries should be followed in coding fractures. Fractures of specified sites are coded individually by site in accordance with both the provisions within categories S02, S12, S22, S32, S42, S49, S52, S59, S62, S72, S79, S82, S89, S92 and the level of detail furnished by medical record content.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

  1. A 7th character applies in this family. Confirm the documented encounter matches the character assigned. See the official 7th-character definitions and this code’s variants
  2. Laterality is coded in this family. Confirm the documented side matches the code — the opposite-side siblings are in the relationships section. See the opposite-side sibling codes
  3. 2 Excludes1 entries — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes
  4. 7 Excludes2 entries — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

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

Other codes that name S82.64XN 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 Excludes1 notes across 2 chapters: M84.3 — Stress fracture (via S82.-), M84.4 — Pathological fracture, not elsewhere classified (via S82.-), S81 — Open wound of knee and lower leg (via S82.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 14 Excludes2 notes across 2 chapters: M23 — Internal derangement of knee (via S82.-), S72 — Fracture of femur (via S82.-), S82.4 — Fracture of shaft of fibula (via S82.6.-), S90 — Superficial injury of ankle, foot and toes (via S82.-), S90-S99 — Injuries to the ankle and foot (S90-S99) (via S82.-), S91 — Open wound of ankle, foot and toes (via S82.-), S92 — Fracture of foot and toe, except ankle (via S82.-), S93 — Dislocation and sprain of joints and ligaments at ankle, foot and toe level (via S82.-), S94 — Injury of nerves at ankle and foot level (via S82.-), S95 — Injury of blood vessels at ankle and foot level (via S82.-), S96 — Injury of muscle and tendon at ankle and foot level (via S82.-), S97 — Crushing injury of ankle and foot (via S82.-), S98 — Traumatic amputation of ankle and foot (via S82.-), S99 — Other and unspecified injuries of ankle and foot (via S82.-).

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

MS-DRG Grouper Relationships (FY2026)

Not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity.

Potential MS-DRG participation — not a DRG assignment.

Named in the grouper logic of 3 MS-DRGs: DRG 564 (MDC 08), DRG 565 (MDC 08), DRG 566 (MDC 08).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):INJ042 — Fracture of lower limb (except hip), subsequent encounter (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same condition, opposite side

Same category and title, differing only in which side of the body is affected.

S82.65XN — Nondisplaced fracture of lateral malleolus of left fibula, subsequent encounter for open fracture type IIIA, IIIB, or IIIC with nonunion (left)Compare S82.64XN vs S82.65XN →, S82.66XN — Nondisplaced fracture of lateral malleolus of unspecified fibula, subsequent encounter for open fracture type IIIA, IIIB, or IIIC with nonunion (unspecified)Compare S82.64XN vs S82.66XN →

Same injury, other encounter phase

Same injury, coded at a different phase of treatment via the 7th character.

S82.64XA — Nondisplaced fracture of lateral malleolus of right fibula, initial encounter for closed fractureCompare S82.64XN vs S82.64XA →, S82.64XB — Nondisplaced fracture of lateral malleolus of right fibula, initial encounter for open fracture type I or II, S82.64XC — Nondisplaced fracture of lateral malleolus of right fibula, initial encounter for open fracture type IIIA, IIIB, or IIIC, S82.64XD — Nondisplaced fracture of lateral malleolus of right fibula, subsequent encounter for closed fracture with routine healing, S82.64XE — Nondisplaced fracture of lateral malleolus of right fibula, subsequent encounter for open fracture type I or II with routine healing, S82.64XF — Nondisplaced fracture of lateral malleolus of right fibula, subsequent encounter for open fracture type IIIA, IIIB, or IIIC with routine healing, S82.64XG — Nondisplaced fracture of lateral malleolus of right fibula, subsequent encounter for closed fracture with delayed healing, S82.64XH — Nondisplaced fracture of lateral malleolus of right fibula, subsequent encounter for open fracture type I or II with delayed healing, S82.64XJ — Nondisplaced fracture of lateral malleolus of right fibula, subsequent encounter for open fracture type IIIA, IIIB, or IIIC with delayed healing, S82.64XK — Nondisplaced fracture of lateral malleolus of right fibula, subsequent encounter for closed fracture with nonunion, S82.64XM — Nondisplaced fracture of lateral malleolus of right fibula, subsequent encounter for open fracture type I or II with nonunion, S82.64XP — Nondisplaced fracture of lateral malleolus of right fibula, subsequent encounter for closed fracture with malunion, S82.64XQ — Nondisplaced fracture of lateral malleolus of right fibula, subsequent encounter for open fracture type I or II with malunion, S82.64XR — Nondisplaced fracture of lateral malleolus of right fibula, subsequent encounter for open fracture type IIIA, IIIB, or IIIC with malunion, S82.64XS — Nondisplaced fracture of lateral malleolus of right fibula, sequela

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Fracture of lower limb (except hip), subsequent encounter).

+4697 more

Contextual Map

Every relationship of S82.64XN 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 S82.64XN with these 11 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

Referenced by Excludes2 notes (14)

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 08 — Diseases and Disorders of the Musculoskeletal System and Connective Tissue[MDC crossing]: “Diseases and Disorders of the Musculoskeletal System and Connective Tissue — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 18,508 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Nearest codes (40)

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

Does S82.64XN require a 7th character?

Yes. The appropriate 7th character is to be added to all codes from category S82.

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
Coding guidelines Official source data
ICD-10-CM Official Guidelines for Coding and Reporting (FY2026), quoted by section 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
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 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

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Nondisplaced fracture of lateral malleolus of right fibula, subsequent encounter for open fracture type IIIA, IIIB, or IIIC with nonunion

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to S82.64XN in its code family, with their registry titles.

View all codes in the S82 family