Glossary · Clinical

Comminuted fracture

A comminuted fracture is one in which the bone is shattered into three or more fragments at the fracture site. It typically results from high-energy trauma and requires precise documentation of displacement status, anatomic location, and laterality to support accurate ICD-10-CM coding and appropriate treatment-level CPT selection.

Verified May 8, 2026 · 8 sources ↓

Drawn from AAPCCMSAMAVitruvianhealthDoctorsmanagement

Definition

Source · Editorial summary grounded in 8 cited references ↓

In a comminuted fracture, the bone fails catastrophically, producing multiple fragments rather than a clean two-piece break. High-velocity mechanisms—motor vehicle collisions, crush injuries, gunshot wounds—are the most common causes, though severely osteoporotic bone can comminute under surprisingly low loads. The multi-fragment pattern distinguishes comminuted fractures from simpler fracture morphologies (transverse, oblique, spiral) and carries direct implications for surgical complexity and healing trajectory.

A segmental fracture is a closely related but distinct subtype: it features at least two separate fracture lines that isolate a discrete segment of bone, usually along the diaphysis of a long bone. Both patterns appear in ICD-10-CM under their own code descriptors, so conflating them produces a specificity error. When comminution is severe enough to involve significant bone loss or a massively contaminated open wound, Gustilo Grade IIIB or IIIC classification may apply, adding another coding axis—the seventh-character extender—to the diagnosis code.

From a treatment standpoint, comminuted fractures more often require open reduction and internal fixation (ORIF) than simpler patterns, though CPT guidelines make clear that fracture type (open vs. closed, simple vs. comminuted) does not dictate treatment category (closed, percutaneous, or open). A closed comminuted fracture may still be treated with open surgical techniques, and the CPT code chosen must reflect the treatment method actually used, not the fracture morphology.

Why it matters

Failing to specify 'comminuted' in fracture documentation forces a coder to fall back on a less-specific ICD-10-CM code, which can misrepresent injury severity, reduce risk-adjustment accuracy, and trigger payer queries or denials on claims for complex ORIF procedures. When comminution is also part of an open fracture, the Gustilo classification determines the seventh-character extender; a missing or incorrect extender (e.g., using 'B' for open fracture NOS instead of 'C' for Gustilo IIIB) directly affects reimbursement under prospective payment models and exposes the claim to NCCI audit risk. Surgeons who document only 'fracture, femur shaft' instead of 'displaced comminuted fracture of shaft of right femur' leave coders unable to assign the appropriate specificity code—such as S72.353A—and understate the procedural complexity that supports modifier -22 or a higher-weighted ORIF code.

Common mistakes

Where people most often go wrong with this concept.

Source · Editorial brief grounded in cited references ↓

Documenting 'comminuted' without specifying displaced vs. nondisplaced—ICD-10-CM requires both axes for most long-bone fractures, and 'displaced' is not a safe default assumption.
Confusing comminuted fractures with segmental fractures and using their ICD-10-CM codes interchangeably; a segmental fracture isolates a discrete bone segment between two fracture lines and has its own distinct codes (e.g., S72.361X vs. S72.353X).
Selecting a CPT treatment code based on fracture morphology rather than treatment method—CPT guidelines explicitly state there is no coding correlation between fracture type and treatment type, so a comminuted fracture treated closed is coded as closed treatment regardless of fragment count.
Omitting laterality in the ICD-10-CM code—over a third of ICD-10 expansion was driven by laterality specificity, and 'unspecified' codes draw heightened scrutiny from payers and risk-adjustment programs.
Failing to append modifier -22 (Increased Procedural Services) when extensive comminution added significant operative time or complexity beyond the typical ORIF, without including a supporting narrative in the claim.
Not documenting Gustilo classification when a comminuted fracture is also open—without it, coders must default to the Type I/II seventh character, which may underrepresent injury severity and associated resource use.
Reporting separate CPT fracture codes for multiple comminuted fragments of the same bone in one encounter; NCCI policy restricts multiple units of service for closed treatment of the same bone, and a single code with modifier -22 or modifier -59 (where clinically appropriate) is the correct approach.

Related codes

Codes commonly involved when this concept appears in practice.

CPT

Modifiers

22 Increased procedural services 59 Distinct procedural service LT Left side RT Right side

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 8 cited references ↓

01Does a comminuted fracture always require surgical treatment?

No. Fragment count does not determine treatment method. Some comminuted fractures, particularly in certain locations or low-energy injuries in elderly patients, are managed with closed treatment and immobilization. CPT guidelines confirm that fracture morphology and treatment type are independent coding axes.

02What is the difference between a comminuted fracture and a segmental fracture for coding purposes?

A segmental fracture has at least two distinct fracture lines that isolate a segment of bone, typically along a long-bone diaphysis. A comminuted fracture simply means three or more fragments. ICD-10-CM assigns separate codes to each pattern—for example, S72.353X for comminuted shaft of femur versus S72.361X for segmental shaft of femur—so they cannot be used interchangeably.

03Why does the Gustilo classification matter for a comminuted fracture?

When a comminuted fracture is also open, the Gustilo grade determines the seventh-character extender in ICD-10-CM. Gustilo IIIB and IIIC fractures—which often involve severe comminution with extensive soft-tissue damage—map to character 'C' rather than 'B', reflecting higher injury severity and resource intensity. Using an incorrect extender misrepresents the encounter and can affect payment under prospective systems.

04Can modifier -22 be used for a comminuted fracture repair?

Yes, when operative documentation clearly supports that the comminution required substantially greater work than a typical fracture of the same type—such as prolonged operative time, additional implants, bone grafting, or vascular repair. The claim must include a narrative explaining the added complexity; modifier -22 without supporting documentation is a common audit trigger.

05If a patient has multiple comminuted fragments in the same bone, should multiple CPT codes be reported?

Generally no. NCCI policy limits reporting to a single unit of service for closed treatment of the same bone in one encounter. For open treatment, the CPT code already encompasses the full ORIF of that bone. If the complexity is exceptional, modifier -22 with a supporting narrative is the appropriate path rather than stacking fracture codes.

06What seventh character should be used for the initial surgical encounter of a comminuted open femur fracture classified as Gustilo IIIB?

The seventh character 'C' applies to initial encounters for open fractures classified as Gustilo IIIA, IIIB, or IIIC. For a Gustilo IIIB comminuted shaft fracture of the right femur at initial encounter, the correct code is S72.351C. Subsequent encounters with routine healing use 'F'; nonunion uses 'N'.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira AI Scribe

When Mira detects documentation of a comminuted fracture, it prompts for the following data points before finalizing code and modifier selection: 1. DISPLACEMENT STATUS — Confirm whether the fracture is displaced or nondisplaced. Do not assume; both options map to distinct ICD-10-CM codes and the distinction affects severity scoring. 2. LATERALITY — Capture right, left, or bilateral explicitly. 'Unspecified' codes are a payer red flag and a risk-adjustment gap. 3. ANATOMIC LOCATION — Document shaft, proximal, distal, or named region (e.g., intertrochanteric, supracondylar). Location drives both the ICD-10-CM category and the CPT code family. 4. OPEN vs. CLOSED — If open, document the Gustilo grade (I, II, IIIA, IIIB, or IIIC). This is required for the seventh-character extender and affects OPPS/ASC payment weight. 5. COMMINUTED vs. SEGMENTAL — If the operative report or imaging distinguishes a discrete isolated bone segment between two fracture lines, the correct pattern is segmental, not comminuted. Mira will flag potential mismatches between operative report language and diagnosis code selection. 6. TREATMENT METHOD — CPT code selection is based on the treatment provided (closed, percutaneous, open), not on fracture morphology. Mira will not infer open treatment from comminuted pattern alone; it requires explicit surgeon documentation of the approach. 7. COMPLEXITY FLAGS — If operative notes describe significantly increased time, additional implants, bone grafting, or vascular repair necessitated by comminution, Mira will surface modifier -22 as a candidate and prompt for a supporting complexity narrative to accompany the claim.

See Mira's approach

Related terms

Pathologic fracture Clinical

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.