Jones fracture of the 5th Metatarsal

Courtesy: Prof Nabil Ebraheim, Unviersity of Toledo, Ohio, USA

 

 Jones fracture is a fracture of the base of the fifth metatarsal.

• First described by British surgeon Robert Jones, who sustained the fracture while dancing.

Definition and Location

• Occurs at the metaphyseal–diaphyseal junction of the fifth metatarsal.
• Extends into the intermetatarsal joint between the fourth and fifth metatarsals.
• Located distal to the metatarsocuboid joint.
• Typically occurs ~1–1.5 cm distal to the tuberosity of the fifth metatarsal.

Relevant Anatomy

• Fifth metatarsal has head, neck, shaft, and tuberosity.
• Base of the fifth metatarsal articulates with:
  • Cuboid bone  metatarsocuboid joint
  • Fourth metatarsal  intermetatarsal joint

Blood Supply

• Tuberosity region receives blood from multiple metaphyseal arteries.
• A nutrient artery supplies intramedullary branches with retrograde flow.
• Fractures distal to the tuberosity may disrupt the nutrient artery, creating relative avascularity.
• Limited blood supply contributes to delayed healing or nonunion.

Tendon and Soft Tissue Attachments

• Peroneus brevis tendon inserts at the tuberosity of the fifth metatarsal.
• Plantar fascia (lateral band) attaches to the fifth metatarsal.
• Tendon pull can separate fracture fragments and impair healing.

Clinical Considerations

• Fractures may be mistaken for lateral foot or ankle sprains, which are common in this region.

Classification of Proximal Fifth Metatarsal Fractures

• Zone 1 – Avulsion fracture
  • Occurs at the tuberosity.
  • Also called pseudo-Jones fracture.
  • Usually treated conservatively.
• Zone 2 – True Jones fracture
  • Occurs at the metaphyseal–diaphyseal junction.
  • Involves the articulation between the fourth and fifth metatarsals.
  • Higher risk of nonunion due to limited blood supply.
• Zone 3 – Stress fracture
  • Occurs distal to the fourth–fifth intermetatarsal articulation.
  • Usually chronic stress injuries.
  • May be associated with cavovarus foot deformity.

Pediatric Consideration

• Normal apophysis (growth plate) appears between ages 9–14.
• The apophysis runs parallel to the shaft of the fifth metatarsal and can mimic a fracture on imaging.

Imaging Findings

• X-rays confirm fracture and location.
• Acute Jones fracture:
  • Sharp fracture margins.
  • No medullary sclerosis.
• Stress fracture:
  • White fracture line.
  • Medullary sclerosis present.

Treatment

• Non-displaced fractures
  • Immobilization with boot or cast.
  • Non-weight-bearing for 6–8 weeks.
  • About 75% heal with conservative treatment.
• Displaced fractures or athletes
  • Intramedullary screw fixation commonly performed.

Surgical Considerations

• Fifth metatarsal appears straight on lateral view and curved (lateral bow) on AP view.
• Lateral bow can create surgical complications.
• Risk of medial cortex perforation at the mid-shaft.
• Intramedullary canal is narrower in the plantar–dorsal dimension.
• Entry point for screw or guide wire is not exactly centered due to anatomy and the metatarsocuboid joint.

Screw Fixation Guidelines

• Each metatarsal should be evaluated individually for screw size and placement.
• Screw should be parallel to the shaft in the lateral plane.
• Avoid directing the screw plantarward.
• Avoid injury to the sural nerve.
• Common screw size: 4.5 mm cancellous screw.
• Typical screw length: 40–50 mm.
• Screw diameter depends on intramedullary canal width.
• Small screw – unstable fixation.
• Oversized screw – fracture displacement.
• Screw must cross the fracture site.

Causes of Fixation Failure

• Poor blood supply to the fracture area.
• Premature return to activity before complete radiographic healing.