Ankle Sprain

Injury to the ankle ligaments from forced inversion (about 85% of cases, lateral ligament complex: anterior talofibular ligament first, then calcaneofibular and posterior talofibular ligaments), eversion (the deltoid ligament, uncommon), or forced external rotation and dorsiflexion (high ankle sprain of the syndesmosis).

• It is among the commonest musculoskeletal injuries, accounting for about 10 to 15% of sports injuries and up to 25% of all sports related injuries in some basketball, football and running populations. About 2 million cases per year occur in the United States alone.
• Grades:
  • Grade 1: stretch, minimal swelling, able to bear weight.
  • Grade 2: partial tear, moderate swelling and bruising, painful weight bearing, mild instability.
  • Grade 3: complete rupture, severe swelling and bruising, marked instability, unable to bear weight.
• Risk factors: previous ankle sprain (the strongest), poor balance and proprioception, high body mass index, high risk sports (jumping, cutting), uneven surfaces, and unsuitable footwear.
• About 20 to 40% develop chronic ankle instability, with recurrent giving way, and up to 30% have symptoms for more than a year.

• A history of a twisting injury with a pop, immediate pain, swelling, bruising (appearing over 24 to 48 hours), difficulty bearing weight, and a feeling of instability.
• Tenderness over the anterior talofibular ligament, anterior and inferior to the lateral malleolus, and over the ligament complex. Ecchymosis tracks to the foot and toes.
• Special tests (best performed 4 to 7 days after injury, when swelling has settled): anterior drawer test (anterior talar translation, anterior talofibular ligament), talar tilt (calcaneofibular ligament), and for syndesmosis injury, tenderness proximal to the ankle joint over the interosseous membrane, a positive squeeze test, and a positive external rotation stress test.
• Features that suggest fracture and need X-ray: bony tenderness at the posterior edge or tip of either malleolus (distal 6 cm), bony tenderness at the base of the fifth metatarsal or the navicular, and inability to take 4 steps immediately after injury and in the clinic.
• Differential diagnosis: fracture (malleolar, fifth metatarsal base, lateral process of the talus, anterior process of the calcaneus, osteochondral lesion of the talus), syndesmosis injury, peroneal tendon tear or subluxation, Achilles tendon rupture, deltoid ligament injury, subtalar sprain, Maisonneuve fracture (proximal fibula, with a medial ankle injury), midfoot (Lisfranc) injury, tarsal coalition, and nerve injury.
• Complications: chronic instability, recurrent sprains, osteochondral lesion, peroneal tendon injury, post-traumatic osteoarthritis, chronic pain, impingement, and deep vein thrombosis (rare) when immobilised.

• Examination of the whole lower leg (including the proximal fibula and the foot), neurovascular status, and gait.
• X-ray of the ankle (anteroposterior, mortise and lateral) and the foot if there is bony tenderness at the malleoli, the fifth metatarsal base or the navicular, or the patient cannot take 4 steps. Weight bearing views if the syndesmosis is suspected.
• MRI or ultrasound for persistent pain beyond 6 weeks, suspected osteochondral lesion, syndesmotic injury, tendon tear, or occult fracture. CT for complex fractures.
• Stress radiographs help assess chronic instability.

• Early care for the first 3 to 5 days:
  • Protect with a brace or splint, relative rest, ice 15 to 20 minutes every 2 to 3 hours in the first days, compression with an elastic bandage or tubular support, and elevation.
  • Avoid heat, alcohol and massage in the first 48 to 72 hours.
  • Paracetamol 1 g orally 6 hourly, with ibuprofen 400 mg orally 8 hourly with food, or naproxen 500 mg 12 hourly, for 3 to 7 days (up to 2 weeks). Topical diclofenac 1% gel 2 to 4 g 3 to 4 times daily is an alternative.
• Weight bearing as tolerated from the first day (early mobilisation gives faster return to work and sport than prolonged immobilisation), using crutches for the first days for comfort if needed.
• Grade 1: elastic support or a lace up brace, with early range of movement, and return to activity in 1 to 3 weeks.
• Grade 2: a semi-rigid stirrup brace or lace up brace for 2 to 4 weeks (up to 6 weeks for sport), with early movement and supervised rehabilitation, return in 3 to 6 weeks.
• Grade 3: a removable boot or rigid brace for 1 to 3 weeks, then a functional brace for 4 to 6 weeks, with supervised rehabilitation. Cast immobilisation is reserved for pain that prevents walking, for up to 10 days. Return in 6 to 12 weeks. Complete ruptures in elite athletes may be considered for early surgical repair, though functional treatment gives similar results in most.
• Rehabilitation (the most important step to prevent recurrence), begun as soon as pain allows:
  • Range of movement: ankle circles and alphabet exercises, calf stretching.
  • Strengthening: resistance band eversion, inversion, dorsiflexion and plantarflexion, calf raises, peroneal strengthening, 3 sets of 10 to 15, daily or on alternate days.
  • Balance and proprioception: single leg stance (eyes open then closed, then on an unstable surface), wobble board, 5 to 10 minutes daily for 6 to 12 weeks.
  • Functional and sport specific drills, hopping, agility and cutting, before return to sport.
  • Bracing or taping for 6 to 12 months on return to high risk sport.
• High ankle (syndesmosis) sprain: protected weight bearing in a boot for 2 to 6 weeks, with a longer recovery (6 to 12 weeks or more). Surgical stabilisation with a suture button or screw for unstable injuries or those with widening.
• Chronic ankle instability (recurrent giving way after 3 to 6 months of rehabilitation): reconstruct the lateral ligaments by anatomical repair (Brostrom type) with or without augmentation, with success of about 85 to 90%. Arthroscopy treats osteochondral lesions, impingement and loose bodies.
• Do not give routine corticosteroid injection. Venous thromboembolism prophylaxis is not routine for isolated sprains. Consider enoxaparin 40 mg subcutaneously daily only if immobilised with other risk factors.
• Special groups:
  • Children: the physis is weaker than the ligament, so tenderness over the growth plate means a Salter-Harris I fracture until proved otherwise. Splint and review.
  • Elderly: screen for falls, osteoporosis, neuropathy and fracture.
  • Diabetes and neuropathy: lower threshold for X-ray, because of Charcot neuroarthropathy.
  • Pregnancy: brace, ice, paracetamol and rehabilitation. Avoid NSAIDs after 20 weeks.
  • Athletes: return when pain free with full range, strength at least 90% of the other side, and sport specific tests passed.
• Follow up: review at 1 week and again at 4 to 6 weeks. Refer to orthopaedics or sports medicine for suspected fracture, syndesmosis injury, grade 3 injury in an athlete, or persistent pain or instability beyond 6 weeks.