Musculoskeletal Imaging

What Imaging Is Best for a Suspected Lisfranc Injury After Normal Radiographs?

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What Imaging Is Best for a Suspected Lisfranc Injury After Normal Radiographs?

A 28-year-old soccer player presents to the urgent care clinic after a twisting injury to their midfoot during a match. They report immediate, severe pain and are unable to bear weight. On examination, there is marked tenderness over the tarsometatarsal joints and significant swelling. Initial weight-bearing radiographs of the foot are obtained and read as negative for acute fracture or dislocation. Despite the normal radiographs, your clinical suspicion for a significant ligamentous injury, such as a Lisfranc disruption, or an occult fracture remains high. This article details the American College of Radiology (ACR) recommended imaging workflow for this specific, high-stakes clinical scenario. For this presentation, the ACR rates MRI of the foot without IV contrast as Usually Appropriate.

Who Fits This Clinical Scenario for Foot Trauma?

This guidance applies to a specific subset of patients with acute foot trauma: adults or children older than five years of age who have a compelling clinical picture for a serious injury despite unrevealing initial radiographs. The key inclusion criteria are:

  • An acute traumatic event.
  • High clinical suspicion for a Lisfranc injury, tendon rupture, occult (hidden) fracture, or subtle dislocation.
  • Initial radiographs that are either completely normal or equivocal, failing to explain the severity of the patient’s symptoms.

This workflow is distinct from other common foot trauma presentations. This article does not apply to:

  • Patients with clear findings on initial radiographs. If a fracture or dislocation is already identified, the imaging question shifts to preoperative planning, not initial diagnosis.
  • Patients with suspected penetrating trauma or a retained foreign body. This is a separate clinical question that often requires different imaging modalities to identify materials like glass or wood.
  • Patients with chronic foot pain or atraumatic symptoms. The differential diagnosis and imaging approach are different for conditions like stress fractures (outside an acute trauma context), plantar fasciitis, or arthritis.
  • Children under 5 years of age. Younger children have different injury patterns and considerations, such as physeal injuries or Toddler’s fractures, which may alter the imaging approach.

What Diagnoses Are You Working Up in This Scenario?

When initial radiographs are negative in the setting of severe foot trauma, advanced imaging is used to investigate injuries that are invisible on plain film. The differential diagnosis is focused on consequential injuries that, if missed, can lead to long-term disability, chronic pain, and post-traumatic arthritis.

Lisfranc Injury: This is often the primary concern and represents a spectrum of injuries to the tarsometatarsal (TMT) joint complex. Purely ligamentous Lisfranc injuries, which can cause significant instability, are completely occult on radiographs unless stress views demonstrate diastasis. A missed Lisfranc injury can lead to progressive arch collapse and debilitating arthritis, making timely diagnosis critical.

Occult Fracture: Not all fractures are visible on initial radiographs, especially non-displaced fractures through cancellous bone. Common locations for occult fractures in the foot include the navicular, cuboid, cuneiforms, or the base of the metatarsals. Advanced imaging can reveal bone marrow edema, a definitive sign of an acute fracture, guiding appropriate management like non-weight-bearing immobilization.

Tendon or Ligament Rupture: Acute trauma can cause complete or high-grade partial tears of key stabilizing structures. This includes the tibialis posterior tendon, peroneal tendons, or the spring ligament complex. These soft-tissue injuries can cause pain and instability that mimic a fracture, and their diagnosis relies on imaging that provides excellent soft-tissue contrast.

Why Is MRI of the Foot Without IV Contrast the Recommended Study for This Presentation?

The ACR panel designates MRI of the foot without IV contrast as Usually Appropriate for this scenario because it directly visualizes the most likely and most consequential pathologies on the differential diagnosis list.

The primary strength of MRI is its unparalleled soft-tissue contrast. It is the most sensitive and specific non-invasive test for evaluating the integrity of the Lisfranc ligament complex, collateral ligaments, and the major tendons around the foot and ankle. Furthermore, MRI is exceptionally sensitive for detecting bone marrow edema, allowing for the definitive diagnosis of occult fractures that are invisible on both radiographs and sometimes even CT scans.

For this specific clinical question, IV contrast is rated Usually not appropriate. The native contrast between ligaments, fluid, and bone marrow on standard non-contrast sequences is typically sufficient to diagnose the acute traumatic injuries in question. Adding gadolinium-based contrast agents does not usually improve diagnostic yield for these conditions and adds cost, time, and potential (though rare) risk.

Other imaging modalities are also considered by the ACR:

  • CT of the foot without IV contrast is also rated Usually Appropriate. CT provides exquisite detail of bony structures and is excellent for identifying subtle or complex fracture patterns, including small avulsion fractures that may be associated with a Lisfranc injury. However, it cannot directly visualize ligamentous tears or bone marrow edema as well as MRI. CT is a strong alternative if the primary suspicion is a subtle fracture and less so a purely ligamentous injury. It involves a small amount of ionizing radiation (ACR RRL=☢ <0.1 mSv for adults).
  • Ultrasound (US) of the foot is rated May be appropriate. Ultrasound can be useful for evaluating superficial tendons (like the peroneals) and ligaments in real-time. However, it is highly operator-dependent and cannot adequately visualize deep structures like the Lisfranc complex or assess for occult fractures. Its role is generally limited to specific, targeted questions rather than a comprehensive evaluation of a complex midfoot injury.

What’s Next After MRI of the Foot Without IV Contrast? Downstream Workflow

The results of the MRI will directly guide the next steps in management, which often involve consultation with a specialist.

  • If the MRI is positive for a Lisfranc ligament disruption: This finding warrants immediate consultation with an orthopedic or foot and ankle surgeon. Many of these injuries, especially those with any degree of instability, require surgical fixation to restore alignment and prevent long-term complications.
  • If the MRI is positive for an occult fracture: Management depends on the specific fracture’s location and stability. A non-displaced navicular fracture, for example, typically requires a prolonged period of non-weight-bearing in a cast. A Jones fracture at the base of the fifth metatarsal may require surgical intervention. The orthopedic specialist will use the MRI findings to tailor the treatment plan.
  • If the MRI is positive for a complete tendon rupture: This also typically requires surgical consultation for potential repair.
  • If the MRI is negative: A normal MRI provides strong evidence against a significant structural injury. This allows the clinician to confidently reassure the patient and proceed with conservative management. Treatment would focus on a short period of protected weight-bearing, physical therapy to restore range of motion and strength, and symptomatic control with ice and anti-inflammatory medication. If symptoms persist despite a negative MRI and conservative care, re-evaluation by a specialist is warranted.

Pitfalls to Avoid (and When to Get Help)

In the workup of a suspected severe midfoot injury, several common pitfalls can delay diagnosis and impact outcomes.

  • Dismissing the injury based on normal radiographs: The most critical error is to let a “negative” radiograph override high clinical suspicion from the mechanism of injury and physical exam.
  • Delaying advanced imaging: For injuries like a Lisfranc disruption, time to diagnosis is critical. A delay of weeks can compromise the potential for a successful surgical outcome.
  • Ordering the wrong advanced study: Choosing CT when the primary concern is a ligamentous injury may miss the diagnosis, while ordering an unnecessary contrast-enhanced study adds cost and potential risk.
  • Failing to obtain initial weight-bearing radiographs: Before proceeding to advanced imaging, ensure that initial radiographs included weight-bearing views if the patient could tolerate them. These views can sometimes unmask subtle instability not seen on non-weight-bearing films.

If the MRI is negative but the patient remains unable to bear weight or has persistent, severe pain, escalate care to a foot and ankle specialist for a comprehensive re-evaluation.

Related ACR Topics and Tools

For a broader overview of imaging for all foot trauma scenarios, consult our parent guide. For specific questions about other clinical presentations or to explore the evidence behind these recommendations, the following GigHz resources are available.

Frequently Asked Questions

Why is CT also ‘Usually Appropriate’ if MRI is better for ligaments?

CT is also rated ‘Usually Appropriate’ because it provides superior visualization of bone detail. It is the best modality for identifying small or complex fractures, particularly small avulsion fractures at ligament attachment sites that can signify an unstable injury. The choice between MRI and CT often depends on whether the primary clinical suspicion is a purely ligamentous injury (favoring MRI) or a subtle fracture (favoring CT).

Is a weight-bearing CT scan an option in this scenario?

A weight-bearing CT (WBCT) is an advanced imaging technique that can be extremely valuable for assessing subtle instability in the foot, particularly for Lisfranc injuries. However, it is typically considered a problem-solving tool used by specialists after initial advanced imaging, rather than the first-line study after equivocal radiographs. The ACR criteria focus on the most common next step, which is a non-weight-bearing MRI or CT.

If the patient has a contraindication to MRI (e.g., a non-compatible pacemaker), what is the next best test?

If a patient cannot undergo an MRI, a non-contrast CT of the foot is the clear alternative. As noted in the ACR criteria, it is also rated ‘Usually Appropriate.’ While it won’t directly visualize ligamentous tears, it can identify secondary signs of injury such as malalignment, joint space widening, or associated avulsion fractures that would lead to the correct diagnosis and management.

How long should I wait for an MRI in a patient with a suspected Lisfranc injury?

In cases of high clinical suspicion for an unstable injury like a Lisfranc disruption, advanced imaging should be obtained urgently. While it may not need to be performed in the middle of the night, it should ideally be arranged within a few days. A delay in diagnosis can lead to worse functional outcomes and make surgical repair more difficult.

Does this guidance apply to an ankle injury with similar symptoms?

No, this guidance is specific to trauma localized to the foot, particularly the midfoot. While there is clinical overlap, suspected ankle injuries (e.g., syndesmotic injury, talar dome lesion) fall under a different ACR Appropriateness Criteria topic (‘Acute Trauma to the Ankle’) with its own set of recommendations.

Reviewed by Pouyan Golshani, MD, Interventional Radiologist — May 29, 2026