Lisfranc Injury

The Lisfranc joint is the tarsometatarsal (TMT) articulation that anchors the midfoot. Lisfranc injuries — ranging from subtle ligamentous sprains to dramatic fracture-dislocations — are commonly missed, and even a "subtle" Lisfranc ligament disruption leads to progressive midfoot arthritis and disability if not recognized and treated. The injury occurs from axial loading with the foot in plantarflexion (car pedal impact) or from a seemingly minor twist (stepping off a curb).

The classic subtle presentation is a midfoot sprain that fails to improve. Plantar ecchymosis over the arch is a pathognomonic sign.

Non-weight-bearing X-rays are frequently normal. Weight-bearing AP foot X-rays are essential — diastasis between the first and second metatarsal bases (>2 mm) confirms the diagnosis. CT defines bony detail. MRI is most sensitive for purely ligamentous injuries. Plantar arch bruising on exam is highly suspicious.

Any diastasis, fracture-dislocation, or ligamentous injury with demonstrated instability in an active patient requires surgical stabilization.

External patient-education references and related OSI pages for additional background:

• Britannica — Ankle (anatomy)
• AAOS OrthoInfo — patient education library
• OSI glossary — orthopedic terminology in plain language