M84.40XP ICD-10-CM Code: Pathological fracture, unspecified site, subsequent encounter for fracture with malunion
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Inpatient Payment Groups (MS-DRG)
MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0, 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.
Official Registry Overview & Definition
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for M84.40XP in the official ICD-10-CM tabular list.
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).
- collapsed vertebra NEC (M48.5) Compare M84.40XP vs M48.5 →
- pathological fracture in neoplastic disease (M84.5-) Compare M84.40XP vs M84.5 →
- pathological fracture in osteoporosis (M80.-) Compare M84.40XP vs M80 →
- pathological fracture in other disease (M84.6-) Compare M84.40XP vs M84.6 →
- stress fracture (M84.3-) Compare M84.40XP vs M84.3 →
- traumatic fracture (S12.-, S22.-, S32.-, S42.-, S52.-, S62.-, S72.-, S82.-, S92.-) Compare M84.40XP vs S12 →
Excludes2 — Not Included Here
Conditions not covered by this code, but which may be reported alongside it when both are present.
- personal history of (healed) pathological fracture (Z87.311) Compare M84.40XP vs Z87.311 →
- traumatic fracture of bone-see fracture, by site
Change history
No changes recorded for this code — unchanged since the FY2016 baseline of the change ledger.
Verify Before Coding
- Billable — reportable as written.
From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim.
Contextual Map
Every relationship of M84.40XP 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.
Hierarchy
- M00-M99 — Chapter 13: Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) (M00-M99) [Hierarchy]
- M80-M85 — Disorders of bone density and structure [Hierarchy]
Referenced by Excludes1 notes
- M48.4 — Fatigue fracture of vertebra [Excludes1](via M84.4.-): “pathological fracture NOS (M84.4-)” · check together
- M48.5 — Collapsed vertebra, not elsewhere classified [Excludes1](via M84.4.-): “pathological fracture NOS (M84.4-)” · check together
Clinical classification (CCSR)
- MUS015 — Pathological fracture, subsequent encounter [CCSR]
Potential MS-DRG
- DRG 564 — OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITH MCC [MS-DRG]: “OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITH MCC (MDC 08)”
- DRG 565 — OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITH CC [MS-DRG]: “OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITH CC (MDC 08)”
- DRG 566 — OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITHOUT CC/MCC [MS-DRG]: “OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITHOUT CC/MCC (MDC 08)”
MDC crossing · procedures (18508)
- 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.”
- 005T0ZZ — Destruction of Spinal Meninges, Open Approach [Same-MDC procedure]: “Destruction of Spinal Meninges, Open Approach — grouped in MDC 08, the procedure side of this code's crossing.” · check together
- 005T3ZZ — Destruction of Spinal Meninges, Percutaneous Approach [Same-MDC procedure]: “Destruction of Spinal Meninges, Percutaneous Approach — grouped in MDC 08, the procedure side of this code's crossing.” · check together
- 005T4ZZ — Destruction of Spinal Meninges, Percutaneous Endoscopic Approach [Same-MDC procedure]: “Destruction of Spinal Meninges, Percutaneous Endoscopic Approach — grouped in MDC 08, the procedure side of this code's crossing.” · check together
- 005W0Z3 — Destruction of Cervical Spinal Cord using Laser Interstitial Thermal Therapy, Open Approach [Same-MDC procedure]: “Destruction of Cervical Spinal Cord using Laser Interstitial Thermal Therapy, Open Approach — grouped in MDC 08, the procedure side of this code's crossing.” · check together
- 005W0ZZ — Destruction of Cervical Spinal Cord, Open Approach [Same-MDC procedure]: “Destruction of Cervical Spinal Cord, Open Approach — grouped in MDC 08, the procedure side of this code's crossing.” · check together
- and 18503 more
Nearest codes (40)
- M84 — Disorder of continuity of bone [Sibling]
- M84.379 — Stress fracture, unspecified toe(s) [Sibling]
- M84.379A — Stress fracture, unspecified toe(s), initial encounter for fracture [Sibling]
- M84.379D — Stress fracture, unspecified toe(s), subsequent encounter for fracture with routine healing [Sibling]
- M84.379G — Stress fracture, unspecified toe(s), subsequent encounter for fracture with delayed healing [Sibling]
- M84.379K — Stress fracture, unspecified toe(s), subsequent encounter for fracture with nonunion [Sibling]
- M84.379P — Stress fracture, unspecified toe(s), subsequent encounter for fracture with malunion [Sibling]
- M84.379S — Stress fracture, unspecified toe(s), sequela [Sibling]
- and 32 more
Referenced by Other Codes
Clinical classification (AHRQ CCSR):MUS015 — Pathological fracture, 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.
Potential MS-DRG Relationships (FY2026)
Not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity.
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.
Official ICD-10-CM tabular notes on other codes that name M84.40XP or its code family.
2 Excludes1 notes: M48.4 (via M84.4.-), M48.5 (via M84.4.-).
Frequently Asked Questions (FAQ) & Clinical Guidance
Does M84.40XP require a 7th character?
Yes. The appropriate 7th character is to be added to each code from subcategory M84.4:.
Nearest Codes in This Family
Official ICD-10-CM classifications closest to M84.40XP in its code family, with their registry titles.
- M84.40 — Pathological fracture, unspecified site
- M84.40XA — Pathological fracture, unspecified site, initial encounter for fracture
- M84.40XD — Pathological fracture, unspecified site, subsequent encounter for fracture with routine healing
- M84.40XG — Pathological fracture, unspecified site, subsequent encounter for fracture with delayed healing
- M84.40XK — Pathological fracture, unspecified site, subsequent encounter for fracture with nonunion
- M84.40XS — Pathological fracture, unspecified site, sequela
- M84.41 — Pathological fracture, shoulder
- M84.411 — Pathological fracture, right shoulder
- M84.411A — Pathological fracture, right shoulder, initial encounter for fracture
- M84.411D — Pathological fracture, right shoulder, subsequent encounter for fracture with routine healing