When should an adult or child over 5 with an acute ankle injury undergo radiographic imaging according to the Ottawa ankle rule?

Ottawa Ankle Rules for Radiographic Imaging

An adult or child over 5 years with acute ankle injury should undergo radiographic imaging only if they have pain in the malleolar zone AND either: (1) bone tenderness along the distal 6 cm of the posterior edge or tip of either malleolus, OR (2) inability to bear weight for four steps both immediately after injury and in the emergency department. 1, 2

Ankle Radiography Criteria

The American College of Radiology recommends obtaining ankle radiographs when both of the following are present 1, 2:

• Pain in the malleolar zone (required baseline criterion)
• Plus at least ONE of:
  • Bone tenderness along the distal 6 cm of the posterior edge of the tibia or tip of the medial malleolus 1, 2
  • Bone tenderness along the distal 6 cm of the posterior edge of the fibula or tip of the lateral malleolus 1, 2
  • Inability to bear weight (take 4 steps) both immediately after injury AND in the emergency department 1, 2

Midfoot Radiography Criteria

Obtain foot radiographs when both of the following are present 1, 2:

• Pain in the midfoot zone (required baseline criterion)
• Plus at least ONE of:
  • Point bone tenderness at the navicular bone 1, 2
  • Point bone tenderness at the base of the 5th metatarsal 1, 2
  • Inability to bear weight (take 4 steps) both immediately after injury AND in the emergency department 1, 2

Age-Specific Application

• Validated for patients ≥5 years of age with 92-100% sensitivity for detecting ankle fractures 1, 2
• Do NOT apply to children <5 years old as the rules have not been validated in this population and may miss clinically significant fractures 1, 2
• Consider age ≥65 years as an additional criterion for mandatory imaging, as some evidence suggests improved sensitivity (99%) when elderly patients automatically receive imaging, though this reduces specificity 3

Critical Exclusionary Criteria

Do NOT use the Ottawa Ankle Rules in the following scenarios 1, 2:

• Penetrating trauma 1, 2
• Pregnancy 1, 2
• Open skin wounds 1, 2
• Patient transferred with radiographs already obtained 1, 2
• Injuries >10 days old 1, 2
• Return visits for the same injury with continued pain 1, 2
• Polytrauma setting 1, 2
• Altered sensorium or mental status 1, 2
• Neurologic abnormality affecting the foot 1, 2
• Underlying bone disease 1, 2
• Gross deformity or palpable mass 1, 2
• Prosthetic hardware present 1, 2

Clinical Performance

The Ottawa Ankle Rules demonstrate excellent diagnostic accuracy 1, 4, 5:

• Sensitivity: 91-100% for detecting clinically significant fractures 1, 4, 5
• Specificity: 25-45% (intentionally lower to maximize fracture detection) 4, 6
• Reduces unnecessary radiographs by 30-35% when properly implemented 1, 2, 5
• 99% sensitivity when all criteria are properly assessed 1, 2

Standard Radiographic Views When Indicated

When the Ottawa Ankle Rules indicate imaging is necessary 1:

• Three standard views: anteroposterior, lateral, and mortise views 1
• Include the base of the 5th metatarsal distal to the tuberosity 1
• Weight-bearing radiographs preferred when possible, as they provide important information for fractures of uncertain stability 1

Areas NOT Covered by Ottawa Rules

Use clinical judgment for 1, 2:

• Trauma to metatarsal heads 1, 2
• Toe injuries 1, 2
• Penetrating trauma with concern for foreign bodies in soft tissues 1, 2

Common Pitfalls

The most critical error is failing to assess ALL criteria before ruling out imaging. The rules require pain in the relevant zone PLUS at least one additional criterion—pain alone is insufficient 1, 2. Additionally, "inability to bear weight" means inability to take 4 steps at BOTH time points (immediately after injury AND in the emergency department), not just one 1, 2. Missing either assessment point can lead to missed fractures 1, 2.