Question
A 28 year old man had his foot run over by a car. He has midfoot swelling and plantar bruising, and radiographs show a fleck of bone between the first and second metatarsal bases.
- What is the diagnosis and what is the anatomy?
- How would you investigate?
- Outline your management.
Answer
Diagnosis and anatomy
- Lisfranc injury of the tarsometatarsal joint complex
- Lisfranc ligament runs from the medial cuneiform to the base of the second metatarsal
- The recessed second metatarsal base forms the keystone of the transverse arch
- Fleck sign indicates avulsion of the Lisfranc ligament
- Myerson classification describes total, partial and divergent incongruity
Investigations
- Weight bearing AP, oblique and lateral radiographs, looking for loss of alignment of the medial border of the second metatarsal with the middle cuneiform
- Diastasis over 2 mm between the first and second metatarsal bases
- CT for fracture pattern and MRI for subtle ligament injury
- Stress views under anaesthesia if doubt remains
Management
- Stable injuries without diastasis, non weight bearing in a boot for 6 weeks
- Unstable injuries need anatomical reduction once swelling settles
- Fixation with transarticular screws or dorsal bridge plates for the medial column and K wires for the lateral column
- Primary partial arthrodesis for purely ligamentous injuries (Ly and Coetzee, JBJS Am 2006)
- Watch for foot compartment syndrome, and counsel about post-traumatic arthritis
Related pages
Author Contributions
Orthofracs team
Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.