A prospective, cohort study comparing weight-bearing computed tomography with weight-bearing radiography in patients with an acute Lisfranc injury.

Injury to the tarsometatarsal (TMT) joint complex in the midfoot is referred to as a Lisfranc injury. The broad spectrum of these injuries includes simple sprains to severe fracture-dislocations. Variable clinical presentations and radiographic findings make Lisfranc injuries notoriously difficult to detect, especially in the case of subtle ligament injuries. Nowadays, up to 30% of unstable Lisfranc injuries are overlooked or misdiagnosed. This can potentially lead to severe sequelae such as post-traumatic osteoarthritis and foot deformities.

For obvious injuries involving diastasis, subluxation, or dislocation, the diagnosis is relatively easy to establish using any imaging modality. However, for subtle injuries without gross bone separation, a dynamic imaging modality facilitating weight-bearing are to be preferred. Many consider weight-bearing conventional radiography as the current gold standard in acute Lisfranc injury diagnostics. However, conventional radiography is a 2D technique that can neither display nor measure the true dimensions of a detailed 3D object, such as the tarsal bones in the foot. Computed tomography (CT) provides greater accuracy in visualizing bone microarchitecture. In combination with weight-bearing, it can be ideal for detecting minor fractures and occult instability caused by load/stress.

To this day, there are no prospective studies comparing weight-bearing CT and weight-bearing radiography for acute Lisfranc injuries. In the current study, participants will be assigned to non-operative or operative treatment based on Lisfranc joint stability evaluation by the initial weight-bearing CT.

Inclusion Criteria:

• Acute trauma to the midfoot
• Intraarticular fracture and/or avulsion fracture in the TMT joint line (detected on a non-weight-bearing CT)
• Suspicion of a purely ligamentous Lisfranc injury (no radiological fractures but substantial clinical findings in the midfoot region, or evidence of ligamentous damage on a MRI)
• Consent-competent patient

Exclusion Criteria:

• Obvious acute unstable Lisfranc injuries (>2mm dislocation between the medial cuneiform and second metatarsal)
• Injury older than four weeks
• Other major foot/ankle/leg injuries
• Previous foot infection or foot pathology on the affected side
• Previous surgery to the TMT joints, and sequelae after a previous foot injury
• Open injury
• Bilateral injury
• Patients with co-morbidities such as neuropathy and peripheral vascular disease