Jones Fracture Diagnostic Criteria
A Jones fracture is defined as a transverse fracture of the proximal fifth metatarsal at the metaphyseal-diaphyseal junction, located within 1.5 cm distal to the tuberosity 1.
Anatomical Location
The key distinguishing feature is the precise anatomical location:
- Zone 2 fracture: Occurs at the metaphyseal-diaphyseal junction of the fifth metatarsal
- Within 1.5 cm distal to the tuberosity (the bony prominence on the lateral foot)
- Distal to the insertion of the peroneus brevis tendon
This location differentiates it from Zone 1 avulsion fractures (at the tuberosity itself) and Zone 3 proximal diaphyseal shaft fractures (more distal) 2.
Radiographic Identification
Standard three-view foot radiographs (AP, oblique, and lateral) are the initial imaging modality 3. On radiographs, look for:
- Transverse fracture line at the metaphyseal-diaphyseal junction
- Location within 1.5 cm distal to the tuberosity
- Presence or absence of medullary sclerosis adjacent to the fracture site (indicates chronicity)
- Medullary canal obliteration (suggests delayed union or stress fracture)
Important Caveat on Classification
Recent evidence reveals moderate interobserver reliability when distinguishing between Zone 2 (Jones) and Zone 3 (proximal diaphyseal) fractures 4. There is significant crossover in identification, with fair agreement between these adjacent zones. Some experts now suggest referring to all fifth metatarsal base fractures (excluding avulsions) as Jones fractures rather than attempting to distinguish between Zones 2 and 3, since clinical outcomes do not differ significantly between these locations 5.
Clinical Classification
Jones fractures are radiographically classified into three categories based on chronicity 1:
- Acute fracture: Sharp fracture line without sclerosis
- Delayed union: Widening of fracture line with adjacent sclerosis
- Nonunion: Complete medullary sclerosis and canal obliteration
Some classifications also include stress fractures as a distinct category 1.
Pediatric Considerations
In skeletally immature patients, the apophysis must be recognized as a distinct entity 6. Pediatric-specific classifications (Herrera-Soto and Lee systems) offer better prognostic correlation than adult classification systems extrapolated to children.