Ankle Sprain

Aka: Ankle Sprain, Lateral Ankle Sprain

1. See Also
   1. Medial Ankle Sprain
   2. High Ankle Sprain
   3. Ankle Sprain Management
2. Epidemiology
   1. Lateral sprains represent 80-85% of Ankle Sprains
   2. Sports with highest rate of Ankle Sprain
      1. Basketball
      2. Ice skating
      3. Soccer
3. Mechanism
   1. Ankle Inversion with Plantar Flexion
4. Pathophysiology
   1. Anatomy
      1. See Ankle Anatomy
   2. Ligaments (In order of injury)
      1. Anterior talofibular ligament (ATF): Easily injured
      2. Calcaneofibular ligament (CF)
      3. Posterior Talofibular ligament (PTF): Rarely injured
5. Associated Injuries
   1. Peroneal Tendon Injury
      1. Peroneal tendon avulsion Fracture
         1. Distinguish from Jones Fracture
         2. Everts foot and prevents inversion
         3. Palpate lateral foot at its insertion
      2. Hemorrhage at Peroneal Muscle
      3. Peroneal Nerve damage may occur
   2. Bone Injury: Foot
      1. Jones Fracture at fifth Metatarsal metaphysis
         1. Peroneal brevis tendon avulsion Fracture
         2. May require surgery for non-union
      2. Tarsal NavicularFracture (or Stress Fracture)
      3. Lisfranc Injury (uncommon, but high morbidity)
   3. Bone Injury: Fibula
      1. Pott's Fracture-Subluxation
   4. Bone Injury: Talus
      1. Talar Dome Fracture (occurs in 6 to 22% of cases)
      2. Posterior TalusFracture (Medial or Lateral Tubercle)
   5. Bone Injury: Calcaneus
      1. Calcaneus Anterior Process Fracture
6. Differential Diagnosis for delayed healing
   1. Talar Dome Fracture
   2. Reflex Sympathetic Dystrophy
   3. Chronic Tendonitis
   4. Peroneal tendon subluxation
   5. Occult Fracture
      1. Anterior Superior Calcaneus Fracture
      2. Lateral TalusFracture
7. Symptoms
   1. "Pop" heard with injury
   2. Ankle swelling and decreased function
8. Signs
   1. General
      1. Tests more helpful for follow-up
      2. Not as useful in the acute setting
   2. Ankle Anterior Drawer Test
      1. Tests anterior talofibular ligament integrity
   3. AnkleTalar Tilt (Inversion stress test)
      1. Tests calcaneofibular ligament integrity
   4. Crossed-Leg Test
      1. Positive in High Ankle Sprain
   5. Ankle Motor Function (Always assess)
   6. Palpation for Tenderness
      1. Squeeze Test
         1. See High Ankle Sprain
      2. Tenderness over fifth Metatarsal metaphysis
         1. Pain 1.5 cm distal on fifth Metatarsal shaft
         2. May indicate Jones Fracture (see above)
      3. Tenderness over medial malleolus (tibia)
         1. May indicate Growth Plate Fracture in adolescent
      4. Tenderness and swelling over talocrural joint line
         1. May indicate osteochondral Talar Dome Fracture
9. Imaging: Initial
   1. Ankle XRay Indications
      1. See Ottawa ankle rules
   2. Foot XRay Indications
      1. Possible Jones Fracture (see above)
      2. Tenderness at Tarsal Navicular (Medial ankle)
10. Imaging: Delayed healing (suspected Talar Dome OCD)
    1. Indications
       1. Symptomatic beyond 6 weeks
       2. Persistent crepitus
       3. Locking or catching sensation
    2. Imaging
       1. Repeat Ankle XRay and foot XRay
       2. Ankle CT or Ankle MRI
11. Grading
    1. First degree Lateral Ankle Sprain
       1. Mild pain and swelling (able to ambulate)
       2. No mechanical instability
       3. Anterior talofibular ligament stretched
       4. Localized tenderness anteriorly
    2. Second degree Lateral Ankle Sprain
       1. Moderate pain and swelling with Ecchymosis present
       2. Pain with ambulation
       3. Moderate lateral ankle instability
       4. Partial tear of anterior talofibular ligament
    3. Third degree Lateral Ankle Sprain
       1. Severe Ecchymosis and swelling (>4 cm at fibula)
       2. Unable to bear weight
       3. Severe lateral ankle instability
       4. Total disruption of lateral ligaments
          1. Anterior talofibular ligament
          2. Calcaneofibular ligament
       5. Heard "Pop" with immediate pain and swelling
12. Management
    1. See Ankle Sprain Management
13. Prognosis
    1. Outcomes generally good
    2. Full recovery may require months
       1. Severe Lateral Ankle Sprains
       2. Syndesmotic Sprains (High Ankle Sprains)
14. Complications (rare)
    1. Late traumatic arthritis
    2. Chronic instability
15. References
    1. Rifat (1996) Am Fam Physician 53(8):2491-8
    2. Rubin (1996) Am Fam Physician 54(5):1609-18
    3. Sitler (1995) Sports Med 20(1):53-7
    4. Swain (1993) Postgrad Med 90(3):91-100
    5. Wolfe (2001) Am Fam Physician 63(1):93-104