What is the evaluation and management for a sprained ankle, including when to get x-rays?

Evaluation and Management of Ankle Sprains

Use the Ottawa Ankle Rules to determine if radiographs are needed—order X-rays only if there is bony tenderness at the posterior edge of either malleolus (within 6 cm), at the base of the fifth metatarsal, at the navicular bone, or if the patient cannot bear weight for four steps immediately after injury and in your office. 1

Initial Evaluation

History

• Document the mechanism of injury (most commonly plantar-flexion with inversion), timing, and any history of recurrent sprains 1
• Urgent evaluation is required if the patient presents with high pain levels, rapid swelling onset, coldness or numbness in the foot, complete inability to bear weight, or complicating conditions like diabetes 1

When to Order X-Rays: Ottawa Ankle Rules

The Ottawa Ankle Rules have 86-99% sensitivity and 97-99% negative predictive value, correctly ruling out fracture in 299 of 300 patients without radiography 1, 2

Order radiographs if ANY of the following are present:

• Pain on palpation at the posterior edge (6 cm) of the lateral malleolus 1
• Pain on palpation at the posterior edge (6 cm) of the medial malleolus 1
• Pain on palpation at the base of the fifth metatarsal 1
• Pain on palpation of the navicular bone 1
• Inability to bear weight for four steps both immediately after injury and in the emergency department or office 1, 3

Common Pitfall: Do not order radiographs on every ankle injury—only 15% of patients with lateral ankle sprains who receive radiographs actually have a fracture 1

Physical Examination Timing

Critical timing consideration: Do not rely on physical examination in the first 48 hours to distinguish between partial tears and complete ligament ruptures, as excessive swelling and pain limit accurate assessment 1, 2

Re-examine at 4-5 days post-injury when the anterior drawer test achieves optimal sensitivity (84%) and specificity (96%) for detecting lateral ligament rupture 1, 2

Physical Examination Findings

Four findings that indicate 96% likelihood of lateral ligament rupture (Grade III sprain):

• Hematoma present 1
• Pain on palpation around the distal fibula 1
• Positive anterior drawer test 1
• Significant swelling 1

Anterior drawer test technique: With the ankle in slight plantar flexion, stabilize the tibia and pull the heel forward—excessive anterior displacement of the talus compared to the uninjured ankle indicates anterior talofibular ligament tear 1

For high ankle (syndesmotic) sprains: Perform the crossed-leg test by applying pressure to the medial knee—pain in the syndesmosis area indicates injury to the tibiofibular ligaments 1

Advanced Imaging Indications

Reserve MRI for specific scenarios only:

• Suspected high-grade ligament injuries with persistent symptoms 1, 2
• Suspected osteochondral defects 1, 2
• Suspected syndesmotic injuries 1, 2
• Suspected occult fractures 1, 2
• Persistent symptoms after initial treatment period 1, 2

MRI has excellent sensitivity (93-96%) and specificity (100%) for these injuries but is not needed for uncomplicated anterior talofibular ligament ruptures where delayed physical examination is sufficient 1

Ultrasonography has similar sensitivity (92%) to delayed examination but poor specificity (64%) and depends on technician expertise 1, 2

Acute Management: PRICE Protocol

Protection, Rest, Ice, Compression, Elevation

Cryotherapy (first 3-7 days):

• Apply ice to reduce edema, decrease pain, and improve recovery time 1, 3
• Recommended by the American Academy of Family Physicians and American Academy of Orthopedic Surgeons 1

Compression and Support:

• Use semirigid ankle supports or lace-up braces combined with elastic compression wrap to reduce swelling and pain, speed recovery, and protect injured ligaments 1, 3
• These functional supports are superior to prolonged immobilization 1

Elevation:

• Elevate the ankle above heart level to reduce swelling 1

Rest (up to 72 hours initially):

• Limit weight-bearing for the first 72 hours, then transition to early mobilization 1

Pain Control

NSAIDs are recommended (e.g., naproxen, celecoxib, piroxicam) as they improve pain control, decrease swelling, improve function, and speed return to activity compared to placebo 1

Additional options include acetaminophen and mild opioids for severe pain 3

Do not use heat for acute ankle injury 1

Mobilization and Rehabilitation

Early mobilization is critical: Begin functional movement as soon as tolerated—early mobilization speeds healing and reduces pain more effectively than prolonged rest 3, 4

Graded exercise program should include:

• Range of motion exercises 4
• Stretching 4
• Strengthening 4
• Proprioceptive training (ankle disk training) 1, 4
• Neuromuscular exercises 4
• Sport-specific exercises 4

These exercises, particularly those with proprioceptive elements, reduce the risk of recurrent ankle sprains 1

Prevention of Recurrence

Previous ankle sprain is the greatest risk factor for re-injury 2, 3

Prevention strategies for patients returning to sports:

• Ankle braces or lace-up supports 1, 3
• Ankle taping 3
• Focused neuromuscular training program 3
• Regular sport-specific warm-up exercises 3

Common Pitfalls to Avoid

• Do not perform definitive ligament assessment in the first 48 hours—wait until 4-5 days post-injury 1, 2
• Do not order radiographs without applying Ottawa Ankle Rules—this avoids unnecessary imaging in 85% of cases 1, 2
• Do not immobilize for prolonged periods—early functional mobilization with bracing is superior 1, 3, 4
• Do not order MRI routinely—reserve for specific indications of complicated injuries or persistent symptoms 1, 2
• Do not neglect rehabilitation—inadequate rehabilitation leads to chronic instability and recurrence 1, 4