When is an X-ray (x ray) of the ankle recommended?

X-Ray Ankle Recommendations

X-ray imaging of the ankle is recommended when a patient meets any of the Ottawa Ankle Rules criteria: inability to bear weight immediately after injury, point tenderness over the malleoli/talus/calcaneus, or inability to take 4 steps in the emergency department. 1

Ottawa Ankle Rules (OAR) for Patients ≥5 Years Old

The American College of Radiology (ACR) provides clear guidelines on when ankle X-rays should be ordered:

X-rays ARE recommended when:

• Patient meets any of the Ottawa Ankle Rules criteria:
  1. Inability to bear weight immediately after injury
  2. Point tenderness over the medial malleolus, posterior edge or inferior tip of lateral malleolus, talus, or calcaneus
  3. Inability to ambulate for 4 steps in the emergency department
• Patient has exclusionary criteria (e.g., neurologic disorder, peripheral neuropathy) that prevent proper OAR assessment

X-rays are NOT recommended when:

• Patient is able to walk
• No point tenderness over malleoli, talus, or calcaneus
• No exclusionary criteria present

Standard Radiographic Protocol

When X-rays are indicated, the standard protocol includes:

• Three views: anteroposterior (AP), lateral, and mortise views
• Images should include the base of the fifth metatarsal bone 1

While some research suggests two views (AP/lateral) may be sufficient for adults 2, the current ACR guidelines still recommend all three views for comprehensive assessment, particularly in children and adolescents where sensitivity decreases with fewer views 3.

Advanced Imaging Considerations

For persistent ankle pain (>1 week but <3 weeks) with negative initial X-rays:

• MRI ankle without IV contrast OR
• CT ankle without IV contrast

For X-rays showing fracture or potential osteochondral injury:

• CT ankle without IV contrast (preferred for fracture evaluation) OR
• MRI ankle without IV contrast (preferred for osteochondral injury assessment) 1

Important Clinical Considerations

• Avoid manipulating ankle injuries before X-ray unless there is neurovascular deficit or critical skin compromise. Pre-X-ray manipulation significantly increases the risk of requiring re-manipulation (44% vs 18%) 4
• Weight-bearing radiographs provide important information for fractures of uncertain stability
• A medial clear space <4mm confirms stability 1
• Foot or knee radiographs are not routinely indicated with ankle injuries unless specific clinical concerns exist 1

High-Risk Factors for Instability

Be particularly vigilant for X-ray indications when these factors are present:

• Medial tenderness, bruising, or swelling
• Fibular fracture above the syndesmosis
• Bi- or trimalleolar fractures
• Open fracture
• High-energy injury mechanism 1

The OAR have demonstrated 92-99% sensitivity for detecting ankle fractures, with <2% false negatives, making them highly reliable clinical decision tools that can reduce unnecessary radiation exposure and healthcare costs 1, 5.