Summary
The proximal (base) 5th metatarsal can be divided into 3 sections: the tuberosity, metaphysis and diaphysis. The tuberosity articulates with the cuboid while the metaphysis articulates with the base of the 4th metatarsal. The intermetatarsal joints are plane type synovial joints that allow slight gliding movements. The lateral band of the plantar fascia attaches the base of the 5th metatarsal tuberosity. The peroneus brevis muscle, which everts the foot, attaches to the lateral tuberosity.
Blood supply to the proximal 5th metatarsal is via the metaphyseal arteries and nutrient artery. The metaphyseal arteries supply the tuberosity while the metaphysis and proximal diaphysis receive blood supply from the nutrient artery. Fractures of the metaphyseal/diaphyseal junction are therefore more likely to have problems with non-union.
Patients being assessed and managed for lower limb injuries should be assessed for venous thromboembolism (VTE) prophylaxis. Refer to these Clinical Excellence Commission resources:
Classification
Based on anatomical location.
Presentation
Mechanism of injury:
- Tuberosity fracture: inversion with foot in plantar flexion
- Acute metaphyseal/diaphyseal fracture: forefoot adduction
- Proximal diaphyseal stress fracture: repetitive microtrauma
Assess:
- Onset, duration and quality of pain
- Palpate for area of tenderness
- Weight-bearing status (usually possible but painful)
- Neurovascular status
- Evaluate surrounding structures
Imaging
X-ray: AP, lateral and oblique foot views.
Management options, referral urgency and follow-up requirements
Tuberosity fracture
Management options
- Walking boot, e.g. cam boot, for 4–6 weeks as pain dictates
- Weight-bear as tolerated
- No running for 3 months
Referral urgency
- Non-urgent
Follow-up
- GP 4–6 weeks post injury
Acute metaphyseal or diaphyseal fracture
Management
- Short leg backslab, including toes
- Non-weight-bearing
Referral urgency
- Non-urgent
Follow-up
- Fracture clinic or orthopaedic doctor follow-up within 7–10 days
Proximal diaphyseal stress fracture
Management
- Short leg backslab
- Non-weight-bearing
Referral urgency
- Non-urgent
Follow-up
- Fracture clinic or orthopaedic doctor follow-up within 7–10 days
Potential complications
Non- or delayed union, especially with acute metaphyseal or diaphyseal and proximal diaphyseal fractures.
Patient advice
Pain from the fracture and restriction of movement is usual for 2–3 weeks and will require regular analgesia, then analgesia as required.
Care of temporary casts fact sheet
Resources
- 5th metatarsal base fracture
Source: Orthobullets - Koval K, Zuckerman J. Handbook of fractures. Philadelphia: Lippincott Williams and Wilkins; 2002.
- Proximal fifth metatarsal fractures ( NSW Health login required)
Source: UpToDate
Accessed from the Emergency Care Institute website at https://aci.health.nsw.gov.au/networks/eci/clinical/tools/5th-metatarsal