Synopsis
Distinguish simple metatarsal injury from unstable tarsometatarsal disruption, apply foot imaging rules without missing plantar signs, use weight-bearing radiographs and CT appropriately, and protect alignment, skin and long-term midfoot function.
- Expose and inspect the sole as well as the dorsum. Plantar midfoot bruising is a powerful warning for Lisfranc injury and should not be relabelled as a simple sprain after inadequate films.
- Palpate every metatarsal, navicular, cuboid, cuneiform region and tarsometatarsal joint; test pain with gentle forefoot abduction-pronation and compare alignment without forceful stress in an unstable foot.
- Use the Ottawa foot rule in eligible people older than 5 years: midfoot pain plus navicular tenderness, fifth-metatarsal-base tenderness or inability to take four steps indicates foot radiographs.
- Obtain AP, oblique and lateral foot radiographs; weight-bearing bilateral comparison views are preferred for subtle Lisfranc instability when safe and tolerable, but are inappropriate in gross displacement or severe pain.
- Use CT to map fractures and subtle joint displacement and MRI when radiographs and CT remain non-diagnostic but ligamentous Lisfranc injury is still suspected.
- A small fleck between the first and second metatarsal bases, widening or loss of the second-metatarsal to middle-cuneiform alignment supports Lisfranc complex disruption.
- Differentiate fifth-metatarsal tuberosity avulsion from metaphyseal-diaphyseal Jones and proximal diaphyseal stress patterns because protection, union risk and operative thresholds differ.
- Stable aligned injuries can use protected loading and surveillance; unstable Lisfranc displacement, open injury, threatened skin, multiple unstable metatarsals or compartment syndrome needs urgent specialist care.
Key red flags
Plantar midfoot ecchymosis, marked tarsometatarsal swelling, pain with forefoot stress or inability to load after axial or twisting trauma should trigger an urgent Lisfranc pathway even if non-weight-bearing films look normal.
Gross midfoot displacement, skin tenting, open wound, absent pulse or sensory or motor deficit needs immediate reduction or operative escalation before elective cross-sectional planning.
Escalating pain, tense swelling, passive-toe-stretch pain or progressive paraesthesia after crush injury suggests foot compartment syndrome and must not wait for pulse loss.
A proximal fifth-metatarsal fracture at the metaphyseal-diaphyseal junction or proximal diaphysis has greater delayed-union risk than a tuberosity avulsion and needs precise localisation and follow-up.
Investigation priorities
Identify eligible acute-trauma patients who need initial foot radiographs.
Define metatarsal fracture and tarsometatarsal alignment.
Management branches
There is open injury, gross dislocation, skin pressure, neurovascular change or possible compartment syndrome.
- Complete trauma assessment, expose the sole and dorsum and document wounds, compartments, pulses and named nerve function.
- Cover an open wound, give immediate network intravenous prophylaxis, address tetanus and avoid repeated emergency-department probing.
- Urgently reduce gross displacement or skin tenting, apply a padded non-weight-bearing splint and repeat tissue and neurovascular examination.
- Escalate compartment concern, irreducibility, recurrent displacement and vascular change directly to orthopaedic and relevant reconstructive teams.
Clinical and imaging findings show or strongly suggest tarsometatarsal ligament or fracture instability.
- Keep non-weight bearing and obtain adequate weight-bearing comparison films when safe, using CT or MRI for remaining structural questions.
- Treat a demonstrably stable injury in immobilisation with early specialist review and repeat loading assessment before progression.
- Use fixation or selected primary arthrodesis for unstable displaced joints according to column, cartilage, soft tissue and functional demand.
- Advance loading only after clinical and imaging review and monitor arch, push-off, footwear and post-traumatic arthritis over time.