The Most Commonly Missed Foot Injury in the ER

Lisfranc injuries — disruptions of the tarsometatarsal joint complex in the midfoot — are among the most commonly missed significant foot injuries in emergency medicine, with an estimated 20–40% initially misdiagnosed as simple midfoot sprains. This distinction is critically important: a true Lisfranc injury that goes unrecognized and untreated results in chronic midfoot pain, progressive deformity, arthritis, and permanent disability. A “simple midfoot sprain” that resolves with rest and conservative care is a fundamentally different entity.

The Lisfranc joint complex is the articulation between the bases of the metatarsals and the row of tarsal bones in the midfoot. The Lisfranc ligament — a strong interosseous ligament connecting the medial cuneiform to the base of the second metatarsal — is the keystone stabilizer of this complex. When this ligament is torn, the midfoot loses its structural integrity.

Mechanism of Injury

Lisfranc injuries occur by two distinct mechanisms. High-energy mechanisms: motor vehicle accidents, industrial crush injuries, and falls from height produce severe, often obvious midfoot injury with displacement visible on X-ray. Low-energy mechanisms: the commonly missed variety. A seemingly minor injury — twisting the midfoot with the foot plantarflexed (stepping in a hole, a football player with the foot fixed and the body rotating over it, a horse-riding fall, a gymnast’s dismount gone wrong) — can disrupt the Lisfranc complex without causing dramatic swelling or displacement. These low-energy “sprain-pattern” Lisfranc injuries are the ones that end up misdiagnosed.

Warning Signs That Distinguish Lisfranc from Simple Sprain

Several clinical findings should raise suspicion for Lisfranc injury rather than benign midfoot sprain: significant swelling and bruising across the dorsum (top) of the midfoot; plantar ecchymosis (bruising on the sole of the foot at the midfoot) — a very specific sign; inability to bear weight or toe-rise on the injured foot; pain specifically at the tarsometatarsal joints on direct palpation; and the piano key test (pain with vertical stress of individual metatarsal bases). On X-ray, even 1–2 mm of diastasis (widening) between the medial cuneiform and second metatarsal base is significant. Weight-bearing X-rays are essential — non-weight-bearing views can appear normal despite significant instability.

Definitive Diagnosis

CT scanning provides detailed assessment of bony injury — fractures at the base of the second metatarsal or medial cuneiform (fleck sign) indicate ligamentous avulsion. MRI reveals ligamentous injury extent and is the most sensitive modality for ligamentous Lisfranc injuries without bony injury. Weight-bearing X-rays comparing injured to uninjured side demonstrate any alignment difference. Fluoroscopic stress testing under anesthesia provides dynamic assessment when plain imaging is equivocal.

Treatment: Consequences of Missing the Diagnosis

Stable ligamentous Lisfranc injuries can be treated non-surgically with non-weight-bearing cast immobilization for 6–8 weeks — but only truly stable injuries. Any instability — even subtle — requires surgical stabilization. Flexible internal fixation using suture-button devices (TightRope) or rigid screws across the unstable joints restores and maintains alignment. Primary arthrodesis (fusion) at the time of initial injury is increasingly performed for the most severe injuries. The consequences of inadequate treatment: progressive tarsometatarsal arthritis, midfoot collapse, chronic pain, and loss of foot function that may eventually require corrective surgery far more complex than the initial reconstruction. If you’ve sustained a midfoot injury, seek evaluation specifically for Lisfranc pathology at Balance Foot & Ankle — (810) 206-1402.

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Dr. Tom Biernacki, DPM

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Dr. Tom Biernacki, DPM is a double board-certified podiatrist and foot & ankle surgeon at Balance Foot & Ankle Specialists in Southeast Michigan. With over a decade of clinical experience, he specializes in heel pain, bunions, diabetic foot care, sports injuries, and minimally invasive surgery. Dr. Biernacki is a member of the APMA and ACFAS, and his patient education content on MichiganFootDoctors.com and YouTube has reached over one million views.