ankle sprain

Classification

(ligament injuries)

Grade 1

• < 25 % tear
• able to continue activity
• swelling occurs hours later
• no laxity when ligament stressed

Grade 2

• 25-75% tear
• unable to continue activity
• swelling within minutes
• laxity mild when ligament stressed, firm end point

Grade 3

• 75%-complete tear
• unable to continue activity
• swelling within minutes
• laxity when ligament stressed, soft end point 'clink'

Etiology

• inversion & plantar flexion: injury to lateral ligaments
  • anterior talofibular ligament injury (generally injured 1st)
  • posterior talofibular ligament
  • calcaneofibular ligament injury
• eversion: injury to medial ligaments (most common)
  • deltoid ligament
  • anterior talofibular ligament
  • interosseous membrane
• high ankle sprain
  • tibiofibular syndesmosis ligament injury

Clinical manifestations

• pain
• swelling
• inability to bear weight
• decreased range of motion
• ecchymosis suggests bleed in the region of a torn ligament
• point tenderness over ligament or insertion point
• diffuse tenderness
• laxity when ligaments stressed (grades II & III)
• high ankle sprain
  • pain & swelling above ankle
  • pain reproduced by squeezing the leg at the mid calf & by having the patient cross the affect leg with the lateral malleolus resting on the opposite knee

Laboratory

• arthrocentesis & joint fluid analysis if septic joint or inflammatory arthritis suspected

Radiology

• ankle & foot radiographs as determined by Ottawa ankle rules
• stress radiographs or arthrograms to differentiate grades II & III

Differential diagnosis

• fracture
  • lateral malleolus
  • medial malleolus
  • dome of talus
  • tarsal navicular
  • proximal 5th metatarsal
• growth place injury
  • in children, the ligaments & joint capsules are 2-5X stronger than the physis, thus growth plate injuries are more common than sprains
• syndesmosis sprains (sprains of the tibiofibular ligament)
• arthritis
  • gout
  • septic joint
  • onset may coincide with or be triggered by trauma
• myositis ossificans
• compartment syndrome
• Achilles tendon rupture

Management

• P: protection.
  • grade 1: Ace wrap
  • grade 2: aircast (air stirrup), soft brace, posterior splint, Unna boot
    • ref (NEJM) does not grade sprain.
    • recommends RICED + air stirrup for what appears to be grade 1 sprain
  • grade 3: cast or referral
• R: rest. crutches with grade 2 or 3, early rehabilitation
• I: ice 1st 24-72 hours. Ice for 10-20 minutes every 1-2 hours
• N: NSAIDs. NSAIDs round the clock not PRN for 1st few days
• C: compression.
  • elastic bandage with or without compression pad around malleolus
  • snug around foot, looser towards the calf
  • objective is to reduce swelling
• E: elevation. Elevate above the heart for 24-48 hours.

• pharmacologic agents
  • non-steroidal anti-inflammatory agents (NSAIDs)
  • narcotic analgesics for grades 2 & 3 as needed
• physical therapy
  • passive range of motion exercises early
    • flexion/extension with towel under ball of foot, toe circles, heel walk toe walk, water exercises in pool
  • wobble board, especially athletes, helps regain proprioception
  • athletes: progress through stages & advance when activity no longer hurts. Stages: walk & run in straight line, run in wide circles, run in figure 8. Football player can practice when he can run 20 yard figure 8 with little or no pain
  • physical therapy does not improve ankle function recovery
• chronic unstable ankles: 3 mm lateral heel & sole wedge to prevent inversion
• if healing is delayed, repeat radiographs at 3-4 weeks
• athletes tape ankle after 1st injury
• braces for recurrent sprains (lace up, air splints)
• consider underlying cause of recurrent sprain

More general terms

• ankle injury

More specific terms

• anterior talofibular ligament injury
• calcaneofibular ligament injury
• tibiofibular syndesmosis ligament injury (high ankle sprain)

Additional terms

• ankle
• Ottawa ankle rules