Glossary · Clinical
Pathologic fracture
A pathologic fracture is a bone break that occurs through an area weakened by an underlying disease process—such as osteoporosis, a neoplasm, or a bone cyst—rather than by an acute high-energy force. The weakened bone fails under stress that would not break a normal, healthy bone.
Verified May 8, 2026 · 9 sources ↓
Definition
Source · Editorial summary grounded in 9 cited references ↓
Pathologic fractures differ fundamentally from traumatic fractures: the causative force is incidental, and the real culprit is the compromised bone. Common underlying conditions include osteoporosis, primary and metastatic bone tumors, osteomyelitis, bone cysts, fibrous dysplasia, Paget's disease, osteogenesis imperfecta, and histiocytosis. A patient may report a trivial fall or minor activity before the fracture, but if that force would not break a structurally normal bone, the fracture is pathologic by definition.
ICD-10-CM routes pathologic fractures to different code categories depending on the etiology: M80 for osteoporosis with current pathologic fracture; M84.4 for stress/insufficiency fractures in diseased bone; M84.5 for fractures in neoplastic disease; and M84.6 for fractures due to other diseases (bone cysts, Paget's, osteomyelitis, fibrous dysplasia, etc.). Chronic fractures are also classified as pathologic under ICD-10-CM. Each code requires a 7th character to indicate encounter type: A for active treatment, D for subsequent encounter with routine healing, G for delayed healing, K for nonunion, P for malunion, and S for sequela.
Documentation of the underlying cause is not optional—it is mandatory for accurate code assignment. Without an explicit physician statement linking the fracture to its disease etiology, a coder cannot assign the correct subcategory and may default to an unspecified or incorrect code. CDI teams should review medication administration records for osteoporosis agents (bisphosphonates, RANK-L inhibitors) and imaging reports for lytic lesions or reduced bone density as triggers for a provider query.
Why it matters
Miscoding a pathologic fracture as a traumatic fracture—or assigning the wrong subcategory—directly affects reimbursement, audit risk, and quality metrics. Payers reimburse the underlying-disease work-up and treatment differently than acute trauma care. For neoplasm-associated fractures, sequencing errors (flipping the fracture code before the neoplasm code when the neoplasm is the treatment focus) can trigger claim denials or medical-necessity disputes. In the inpatient setting, a fracture that occurs after admission may implicate CMS Hospital-Acquired Conditions and AHRQ PSI 08 (in-hospital fall-associated fracture rate), so etiology coding determines whether the event is flagged as a preventable safety incident—a distinction with direct financial and reputational consequences for the facility.
Common mistakes
Where people most often go wrong with this concept.
Source · Editorial brief grounded in cited references ↓
- Assigning a traumatic fracture code (S-series) to a known osteoporotic patient who fell, even when the fall alone would not break a healthy bone—ICD-10-CM guidelines require M80 in that scenario.
- Omitting the underlying etiology code: pathologic fracture codes must be paired with the causative condition (e.g., the neoplasm or metabolic bone disease), not reported in isolation.
- Sequencing the M84.5 fracture code first when the treatment focus is the neoplasm—correct sequencing places the neoplasm code first, fracture code second.
- Sequencing the M84.5 fracture code second when the treatment focus is the fracture itself—in that scenario, M84.5 leads and the neoplasm code follows.
- Using 7th character A (initial/active treatment) only for the very first visit; A applies throughout the entire active treatment phase regardless of whether a new provider is seen.
- Defaulting to an unspecified M84.6 code without documenting the specific 'other disease' (bone cyst, Paget's, fibrous dysplasia, etc.) that caused the fracture.
- Coding insufficiency fractures as traumatic stress fractures rather than M84.4 when no alternative physician-documented etiology overrides the ICD-10-CM default pathologic classification.
- Failing to review home medication lists for bisphosphonate therapy, which signals osteoporosis even if the inpatient MAR does not show an active dose.
Related codes
Codes commonly involved when this concept appears in practice.
CPT
- 27236 $1,089.87Open treatment of a proximal femoral fracture at the femoral neck, using internal fixation hardware or prosthetic replacement to stabilize the fracture site.
- 27244 $1,121.27Open fixation of an intertrochanteric, peritrochanteric, or subtrochanteric femoral fracture using a plate/screw-type implant, with or without cerclage.
- 27245 $1,118.26Open treatment of an intertrochanteric, peritrochanteric, or subtrochanteric femoral fracture using an intramedullary implant, with or without interlocking screws and/or cerclage.
- 23615 $823.67Open surgical treatment of a proximal humeral fracture at the surgical or anatomical neck, with internal fixation and tuberosity repair when performed.
- 25600 $385.45Closed treatment of a distal radius fracture or epiphyseal separation, including the ulnar styloid if fractured, performed without manipulation of the bone fragments.
- 27750 $395.47Closed treatment of a tibial shaft fracture without manipulation, applied when the fracture is nondisplaced or stable enough to maintain alignment without manual reduction.
- 27792 $607.90Open surgical repair of a distal fibula fracture at the lateral malleolus, with internal fixation (plate, screws, or pins) when performed.
- 20225 $364.74Percutaneous bone biopsy using a trocar or needle targeting deep skeletal structures such as the vertebral body or femur.
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 9 cited references ↓
01Can a pathologic fracture be coded if the patient also had a fall?
02Which code comes first when a bone metastasis causes a fracture?
03What 7th character should I use for a follow-up visit three weeks after surgical fixation of a pathologic fracture?
04How is an insufficiency fracture coded under ICD-10-CM?
05Is a bone cyst an acceptable 'other disease' for M84.6?
06Do I need to report both the fracture code and the underlying-disease code?
Sources & references
Editorial content was developed using the following public sources. Last verified May 8, 2026.
- 01ICD-10-CM Official Guidelines for Coding and Reporting FY 2025, Section I.C.13.c.2 and Section I.C.2.l.6 — https://www.cms.gov/medicare/coding/icd10
- 02ICD-10-CM Official Guidelines for Coding and Reporting FY 2015, Section I.C.13.c — https://www.cms.gov/medicare/coding/icd10/downloads/icd10cm-guidelines-2015.pdf
- 03AAPC Orthopedic Coding Alert: Break Down Pathologic Fracture Coding for the Best Dx (Aug 2021) — https://www.aapc.com/codes/coding-newsletters/my-orthopedic-coding-alert/faqs-break-down-pathologic-fracture-coding-for-the-best-dx-169840-article
- 04e4.health CDI Tips & Friendly Reminders: Pathological Fractures — https://www.e4.health/cdi-tips-pathological-fractures/
- 05RACmonitor: The Finer Details of Fractures — https://racmonitor.medlearn.com/the-finer-details-of-fractures/
- 06Independence Blue Cross CDI General Coding Tips: Fractures — https://www.ibx.com/documents/35221/56647/cdi-general-coding-tips-fractures.pdf
- 07CMS Medicare NCCI 2025 Policy Manual, Chapter I — https://www.cms.gov/files/document/01-chapter1-ncci-medicare-policy-manual-2025finalcleanpdf.pdf
- 08AHA Coding Clinic, Second Quarter 2018, p. 12: Osteoporosis and Fracture (Traumatic versus Pathologic)
- 09AHA Coding Clinic, Fourth Quarter 2020, p. 32: ICD-10-CM New/Reviewed Codes: Osteoporosis Related Pathological Fractures
Mira AI Scribe
When Mira detects documentation of a fracture alongside any of the following—osteoporosis diagnosis, active bisphosphonate or denosumab therapy, bone metastasis, primary bone tumor, osteomyelitis, bone cyst, Paget's disease, fibrous dysplasia, or osteogenesis imperfecta—it flags the fracture as potentially pathologic and prompts code-category selection before claim submission. Mira will: 1. Route the encounter to M80 (osteoporosis with fracture), M84.4 (insufficiency), M84.5 (neoplastic), or M84.6 (other disease) based on the documented etiology—not default to the S-series traumatic codes. 2. Enforce correct sequencing: when a neoplasm is the treatment focus, the neoplasm code leads; when the fracture is the treatment focus, M84.5 leads. 3. Prompt the 7th character: A for any active-treatment encounter regardless of visit number; D/G/K/P as healing progresses; S for sequela. 4. Flag missing etiology: if the fracture category requires a linked condition code and none is present in the encounter, Mira surfaces a documentation-gap alert before the claim closes. 5. Surface a CDI query suggestion if the note describes a low-energy mechanism (ground-level fall, minor activity) in a patient on osteoporosis therapy or with imaging suggesting bone pathology, but the physician has not yet stated 'pathologic fracture.' Mira does not auto-assign the diagnosis; the treating provider confirms. All code selections remain subject to physician attestation.
See Mira's approach