Fifth Metatarsal fracture

Courtesy: Prof Amr Abdelgawad, Associate Professor, Texas Tech University, USA

1. Anatomy

• 5th metatarsal base:
  • Insertion of Peroneus brevis tendon
  • Common site of avulsion injuries (inversion)
• Blood supply
  • Poor at metaphyseal–diaphyseal junction
  •  Risk of delayed union / non-union

2. Growth Plate vs Fracture (X-ray Differentiation)

Feature	Growth Plate (Apophysis)	Fracture
Direction	Parallel to metatarsal	Perpendicular / transverse
Age	Appears: ~9 yrs	Any age
Closure	Girls: ~12 yrs, Boys: ~14 yrs	—
Edges	Smooth	Sharp, irregular

Key exam point:
If line is parallel – normal apophysis
If transverse – fracture

3. Mechanism of Injury

• Inversion injury of foot
• Peroneus brevis pulls  avulsion

4. Clinical Presentation

• Pain + swelling over lateral foot
• Tenderness at base of 5th metatarsal
• Difficulty weight bearing

Important:

• Pain at base – Foot X-ray (not ankle)

5. Anatomical Classification

Fractures based on location:

1. Physeal (apophyseal)
2. Metaphyseal
3. Metaphyseal–diaphyseal junction
4. Proximal diaphyseal (stress)

6. Types of Fractures (Most Important for Exams)

1. Avulsion Fracture (Pseudo-Jones)

• Location: Tuberosity (metaphysis)
• Mechanism: Peroneus brevis pull
• Stable

Treatment:

• Weight bearing as tolerated
• Hard sole shoe / boot / bandage
• No follow-up X-ray needed

 2. Metaphyseal Fracture

• Also stable

Treatment:

• Same as above
• Early weight bearing

 3. True Jones Fracture

• Location: Metaphyseal–diaphyseal junction
• (Between 4th & 5th metatarsal articulation)

Important:

• Poor blood supply
• High risk of non-union

Treatment:

• Non-weight bearing cast
• Prolonged immobilization

Athletes:

• Intramedullary screw fixation (early return)

 4. Proximal Diaphyseal Stress Fracture

• Seen in:
  • Athletes
  • Varus foot loading

High risk of non-union

Treatment:

• Often surgical (IM screw)

7. Radiological Landmark for Jones Fracture

• If fracture line:
  • Toward cuboid  Pseudo-Jones (stable)
  • Between 4th & 5th MT – True Jones (unstable)

8. Orthopedic Referral Indications

• Suspected Jones fracture
• Displacement
• Non-union risk
• Athlete needing early return
• Diagnostic uncertainty

9. Key Exam Pearls

• Most common –  Pseudo-Jones (avulsion)
• Most dangerous – True Jones fracture
• Growth plate = parallel line
• Fracture = perpendicular line
• Always:
  “Pain at base  X-ray foot, not ankle”

10. Quick Summary Table

Type	Stability	Blood Supply	Treatment
Avulsion (Pseudo-Jones)	Stable	Good	WBAT, boot
Metaphyseal	Stable	Good	WBAT
Jones	Unstable	Poor	NWB cast / surgery
Stress fracture	Unstable	Poor	Surgery often