Classification system
Hawkins Classification
Hawkins Classification of Talar Neck Fractures
The Hawkins classification grades talar neck fractures by how many of the talus’s articulations are dislocated — none in type I, the subtalar joint in type II, the subtalar and tibiotalar joints in type III, and all three including the talonavicular joint in type IV — and the reported rate of avascular necrosis rises steeply with each type.
What the Hawkins category means
Hawkins scores run from 1 to 4, where a lower score is better. The bands below are conventional reporting categories, not diagnostic cut-offs.
- Undisplaced (type I)1–1
Lowest osteonecrosis risk. Confirm with CT that it is genuinely undisplaced before treating it as one.
- One joint dislocated (type II)2–2
The subtalar joint has failed; the talar body remains in the mortise.
- Two or more joints dislocated (types III–IV)3–4
The talar body is out of the mortise. A surgical emergency, with the highest reported rates of osteonecrosis, open injury and skin compromise.
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 | Avascular necrosis of the talar body: 0% in type I, 42% in type II and 91% in type III in the original series | — | Fifty-seven talar neck fractures reported by Hawkins | — | Hawkins LG 1970 |
| Criterion | Avascular necrosis approximately 13% in type I, 50% in type II, 84% in type III and approaching 100% in type IV | — | Seventy-one talar neck fractures at long-term follow-up, the series that added type IV | — | Canale ST 1978 |
| Criterion | Hawkins sign — subchondral lucency in the talar dome at 6–8 weeks — indicates a vascularised body; its absence is a weaker predictor of necrosis than its presence is of viability | — | Talar neck fractures followed radiographically after fixation | — | Hawkins LG 1970 |
| Criterion | Comminution of the talar neck and open injury predict poor outcome independently of the Hawkins type | — | Contemporary series of operatively treated talar neck fractures | — | Vallier HA 2004 |
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 an undisplaced fracture of the talar neck with all three articulations congruent. Type II is a displaced neck fracture with subluxation or dislocation of the subtalar joint, the talar body remaining in the ankle mortise. Type III is a displaced neck fracture with dislocation of both the subtalar and the tibiotalar joints, so the talar body is extruded from the mortise. Type IV, added by Canale and Kelly, is a type III with additional subluxation or dislocation of the talonavicular joint. The types are ordered by how much of the talar blood supply is stripped: the body is fed retrogradely through the artery of the tarsal canal, branches entering the neck, and deltoid branches, and successive dislocations remove these in turn — which is the mechanism behind the rising rate of avascular necrosis and the reason the classification has survived despite recording nothing about comminution or the state of the soft tissues.
Instrument profile
- Developer
- Leland G. Hawkins; type IV added by S. Terry Canale and Frank B. Kelly Jr.
- Institution
- United States
- First published
- 1970
- Items
- 3
- Response format
- Three radiographic findings, one per articulation
- Score range
- 1 to 4
- Direction
- Lower score = better
- Completion time
- About 1 minutes
- Regions
- Foot & Ankle
- Conditions
- Talar neck fracture, Talus fracture, Avascular necrosis of the talus, Subtalar dislocation
- Procedures
- Open reduction and internal fixation of the talar neck, Emergency reduction of a dislocated talus, Subtalar arthrodesis, Tibiotalocalcaneal arthrodesis
- Validity
- One of the few fracture classifications with a genuine biological basis: the type tracks the number of vascular pedicles disrupted, and the association with osteonecrosis has held across series for fifty years, even as the absolute rates have fallen with early anatomic reduction.
- Reliability
- Agreement is good for the displaced types, where dislocation is obvious, and weakest for the type I–II boundary, because minor displacement at the talar neck is under-read on plain radiographs — CT reclassifies a meaningful proportion of fractures called undisplaced.
When to use the Hawkins
Well suited to
- Classifying a talar neck fracture at presentation to convey both the urgency and the likely vascular consequence.
- Counselling a patient about the risk of avascular necrosis and the length of follow-up they should expect.
- Reporting talar neck fractures in the literature, where this is the universal shorthand.
Limitations and poor fits
- Talar body, lateral process or posterior process fractures, which are separate injuries with their own classifications.
- As a complete description for surgical planning: it records no comminution, no articular impaction and no soft-tissue status, and a CT is required for all of those.
- Classifying from post-reduction films — the type is defined by the displacement at injury, and a reduced type III looks like a type I.
- Quoting the classic osteonecrosis percentages to a patient as though they were current: contemporary series with early anatomic reduction report lower rates, and radiographic osteonecrosis without collapse is often compatible with a functioning ankle.
Hawkins compared with other instruments
Instruments measuring a related construct, with the practical difference between them.
| Instrument | Items | Range | What it adds |
|---|---|---|---|
| Sanders | 3 | 1–4 | The Sanders classification grades displaced intra-articular calcaneal fractures into four types by the number of posterior facet fragments seen on the widest coronal CT image — type I non-displaced, type II two-part, type III three-part and type IV four-part or comminuted — and the type number predicts the outcome of internal fixation. |
| Weber | 3 | 1–3 | The Danis-Weber classification sorts ankle fractures into three types by the level of the fibular fracture relative to the tibiotalar joint line — type A below the syndesmosis, type B at it, and type C above it — because the height of the fibular fracture predicts how much of the syndesmosis is torn. |
| Lauge-Hansen | 2 | 1–4 | The Lauge-Hansen classification is a mechanistic system that sorts rotational ankle fractures into four patterns named for the position of the foot and the direction of the deforming force — supination–adduction, supination–external rotation, pronation–abduction and pronation–external rotation — each staged by how far the predictable sequence of bone and ligament failure has progressed. |
| AO/OTA | 3 | 1–3 | The AO/OTA classification gives every fracture an alphanumeric code in which the first digit is the bone, the second the segment and the letter the fracture type — extra-articular, partial articular or complete articular in an end segment, and simple, wedge or multifragmentary in a shaft — so that 32-A is a simple femoral shaft fracture and 43-C a complete articular pilon fracture. |
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 radiographic classification system. No licence is required.
References
- Hawkins LG. Fractures of the neck of the talus. Journal of Bone and Joint Surgery (American Volume). 1970.
- Canale ST, Kelly FB Jr. Fractures of the neck of the talus: long-term evaluation of seventy-one cases. Journal of Bone and Joint Surgery (American Volume). 1978.
- Vallier HA, Nork SE, Barei DP, Benirschke SK, Sangeorzan BJ. Talar neck fractures: results and outcomes. Journal of Bone and Joint Surgery (American Volume). 2004.
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.