High Ankle Sprain

Aka: High Ankle Sprain, Syndesmotic Sprain, Syndesmosis Sprain

1. Epidemiology
   1. Accounts for up to 10% of Ankle Sprains in high risk populations
   2. Most common sports associated with High Ankle Sprain
      1. Football
      2. Downhill skiing
2. Mechanism
   1. Eversion and Rotation injury
   2. Hyper-dorsiflexion
3. Anatomy
   1. Tibiofibular Syndesmosis injury
      1. Interosseous membrane (IM)
      2. Anterior Inferior tibiofibular ligament (AITF)
   2. Separation of Tibia from fibula
4. Symptoms
   1. Medial ankle pain
   2. Difficulty bearing weight
5. Signs
   1. Minimal external signs of injury (e.g. swelling)
   2. Pain and Disability out of proportion with injury
   3. Ankle may feel spongy
   4. Ankle Squeeze Test positive
   5. Ankle External Rotation Test positive
   6. Crossed-Leg Test positive
   7. Point tenderness over anterior and proximal ankle
      1. Pain at distal tibiofibular joint
6. Associated conditions
   1. Maisonneuve Fracture
      1. Proximal Fibula Fracture
      2. Palpate full length of fibula and tibia on exam
7. Imaging
   1. Ankle XRay
      1. Tibiofibular clear space widening >6 mm indicates complete syndesmotic rupture
   2. Tibia-Fibula XRay
      1. Exclude Proximal Fibula Fracture (Maisonneuve Injury)
   3. Ankle MRI
      1. Persistent Disability in an injury suggestive of High Ankle Sprain
8. Management
   1. No early mobilization
   2. May require internal fixation
9. Prognosis
   1. More disabling than other Ankle Sprains
      1. May require 4-5 months to return to prior functional capacity
   2. Risk of ankle Degenerative Joint Disease
10. References
    1. Molinari (2009) Iowa Orthop J 29:130-8 [PubMed]
    2. Rifat (1996) Am Fam Physician 53(8):2491-8 [PubMed]
    3. Rubin (1996) Am Fam Physician 54(5):1609-18 [PubMed]
    4. Sitler (1995) Sports Med 20(1):53-7 [PubMed]
    5. Swain (1993) Postgrad Med 90(3):91-100 [PubMed]
    6. Wolfe (2001) Am Fam Physician 63(1):93-104 [PubMed]