Classification system
Gustilo-Anderson Classification
Gustilo-Anderson Classification of Open Fractures
The Gustilo-Anderson classification grades open fractures from type I to type IIIC by wound size, degree of soft tissue damage, contamination and vascular injury, and it is the system that drives antibiotic choice, debridement planning and the decision on soft tissue coverage.
What the Gustilo-Anderson category means
Gustilo-Anderson scores run from 1 to 5, where a lower score is better. The bands below are conventional reporting categories, not diagnostic cut-offs.
- Type I1–1
Low-energy, clean, minimal soft tissue injury.
- Type II2–2
Moderate soft tissue damage without extensive stripping.
- Type IIIA3–3
Extensive soft tissue damage with adequate bone coverage.
- Type IIIB4–4
Periosteal stripping and bone exposure requiring flap coverage.
- Type IIIC5–5
Arterial injury requiring repair.
Published criteria and reliability
The published cut-offs that define this instrument, and the measured agreement between observers using it. Each is reported with the population it was derived in.
| Type | Value | Subscale | Population | Follow-up | Source |
|---|---|---|---|---|---|
| Criterion | Type I — infection rate 0–2% | — | Original Gustilo series and subsequent cohorts | — | Gustilo RB 1976 |
| Criterion | Type II — infection rate 2–7% | — | Original Gustilo series and subsequent cohorts | — | Gustilo RB 1976 |
| Criterion | Type III — infection rate rises steeply with subtype, commonly cited from 10% to 50% for IIIB | — | Type III open fractures | — | Gustilo RB 1984 |
| Criterion | Interobserver agreement is moderate, with most disagreement between IIIA and IIIB | — | Orthopaedic surgeons viewing the same injuries | — | Brumback RJ 1994 |
Criterion is a published cut-off, definition or performance figure belonging to a classification or decision rule — it is not a change score and should not be read as one.
How the score is calculated
Stated in full so the calculation can be independently checked, and reproduced by hand if needed.
Type I is a wound under 1 cm with minimal soft tissue damage and a simple fracture pattern. Type II is a wound between 1 and 10 cm with moderate soft tissue damage. Type III covers extensive soft tissue damage and is subdivided: IIIA has adequate soft tissue coverage of bone after debridement, IIIB has periosteal stripping and bone exposure requiring flap coverage, and IIIC has an arterial injury requiring repair. Certain features make a fracture type III irrespective of wound size: segmental fracture with extensive displacement, high-energy mechanism, gross contamination such as a farmyard injury, gunshot or shotgun wounds, traumatic amputation, and presentation more than 8 hours after injury.
Missing data
The classification is a branching assessment. A type IIIC is assigned on the vascular finding alone, and a type I or II is assigned without reference to the coverage question, so not every item is answered for every injury.
Instrument profile
- Developer
- Ramón B. Gustilo and John T. Anderson
- Institution
- Hennepin County Medical Center, Minneapolis
- First published
- 1976
- Items
- 4
- Response format
- Branching assessment made after debridement
- Score range
- 1 to 5
- Direction
- Lower score = better
- Completion time
- About 2 minutes
- Regions
- General Health
- Conditions
- Open fracture, Compound fracture, High-energy trauma
- Procedures
- Debridement, External fixation, Soft tissue coverage, Free flap
- Observer agreement
- Interobserver agreement around 60% for the full five-type system
- Validity
- Type predicts infection risk, non-union and amputation, which is why the system has endured despite its reliability limitations.
- Reliability
- Agreement is best at the extremes and poorest for the IIIA versus IIIB distinction, which is also the distinction that most changes management. Assigning the type after debridement rather than on arrival improves consistency.
When to use the Gustilo-Anderson
Well suited to
- Any open fracture, to guide antibiotic prophylaxis, urgency of debridement and the need for soft tissue coverage.
- Communicating injury severity between emergency, orthopaedic and plastic surgical teams.
- Research and audit, where it remains the standard descriptor for open fracture severity.
Limitations and poor fits
- Before formal debridement, when the wound appearance understates the true zone of injury in high-energy trauma.
- As a sole predictor of limb salvage versus amputation — scores designed for that question, such as the MESS, address it directly.
- Closed fractures, for which the Tscherne classification describes soft tissue injury instead.
Gustilo-Anderson compared with other instruments
Instruments measuring a related construct, with the practical difference between them.
| Instrument | Items | Range | What it adds |
|---|---|---|---|
| MESS | 5 | 1–14 | The Mangled Extremity Severity Score adds four components — skeletal and soft tissue injury, limb ischaemia (doubled if ischaemia exceeds six hours), shock and age — and a total of 7 or more was 100% predictive of amputation in the original series, a threshold that later prospective work found does not hold well enough to decide an individual case. |
| Salter-Harris | 3 | 1–5 | The Salter-Harris classification grades fractures involving the growth plate into five types, from a fracture through the physis alone (type I) to a crush injury of the physis (type V), according to whether the fracture line also involves the metaphysis, the epiphysis, or both. |
Copyright and permitted use
Published openly because it is the question every clinician and researcher asks before using an instrument, and almost nobody answers it.
A published fracture classification system. The type definitions are freely reproducible and no licence is required.
References
- Gustilo RB, Anderson JT. Prevention of infection in the treatment of one thousand and twenty-five open fractures of long bones. Journal of Bone and Joint Surgery (American). 1976.PMID 773941
- Gustilo RB, Mendoza RM, Williams DN. Problems in the management of type III (severe) open fractures: a new classification of type III open fractures. Journal of Trauma. 1984.PMID 6471139
- Brumback RJ, Jones AL. Interobserver agreement in the classification of open fractures of the tibia. Journal of Bone and Joint Surgery (American). 1994.PMID 8083263
Editorial status
This page has not yet been signed off by a named clinical reviewer. The scoring logic is stated in full above so it can be independently verified, and every threshold is traceable to its source. See our editorial methodology.