Ankle Sprain

Ovid: 5-Minute Orthopaedic Consult

Editors: Frassica, Frank J.; Sponseller, Paul D.; Wilckens, John H.
Title: 5-Minute Orthopaedic Consult, 2nd Edition
> Table of Contents > Ankle Sprain

Ankle Sprain
Dennis E. Kramer MD
  • Acute sprains of the lateral ligaments about the ankle are the most common injury in sports (1) and also occur commonly in the general population.
  • Most commonly a partial tear or complete rupture of the ATFL occurs (2).
    • More severe injuries include the CFL (2).
    • Lateral ankle sprain results from an inversion mechanism.
  • Classification (3):
    • Grade I: Partial tear of the ligaments
    • Grade II: Partial to complete tear of the ATFL, partial tear of the CFL
    • Grade III: Complete rupture of the ATFL and CFL
  • Ankle sprains cause sequential disruption of:
    • Anterolateral joint capsule
    • ATFL
    • CFL
  • Primary static restraints to ankle inversion injury:
    • ATFL:
      • Most commonly injured ankle ligament
      • Primary restraint to inversion with ankle plantarflexed
      • Torn in inversion, plantarflexion, and internal rotation
    • CFL:
      • Stabilizes ankle and subtalar joints
      • Tears in inversion with ankle neutral or dorsiflexed
  • Primary dynamic restraints:
    • Peroneal tendons
  • In the United States, ~27,000 of these injuries occur every day (4).
  • Most common athletic injury (1)
Risk Factors
  • Athletes
  • Dancers
  • Children with congenital tarsal coalition
  • Cavovarus foot alignment
The injury results from inversion of the foot with the
ankle in varying degrees of plantarflexion when weight is placed on the
Signs and Symptoms
  • Pain, tenderness, and swelling over the lateral aspect of the ankle
  • Often difficult to bear weight on extremity
  • Mechanism of injury causing sprain:
    • Inversion in plantarflexion: ATFL injury
    • Inversion in dorsiflexion: CFL injury
Physical Exam
  • Tenderness and swelling are noted along
    the lateral aspect of the ankle inferior and anterior to the tip of the
    lateral malleolus.
  • Perform manual strength testing of muscle groups, including the peroneal tendons.
  • Assess the neurovascular status of the
    limb, including the superficial peroneal nerve that can sustain a
    stretching injury with inversion sprain.
  • Assess the ligament stability of the ankle.
    • Compare with the uninjured ankle.
    • Anterior drawer test:
      • Evaluates ATFL stability
      • Holding the distal tibia firmly with one
        hand, place the other hand around the heel and displace the hindfoot
        anteriorly with the ankle in a neutral position.
    • Inversion tilt test:
      • Evaluates CFL stability
      • Position ankle in neutral dorsiflexion.
      • Stabilize distal tibia with 1 hand and apply inversion force to hindfoot with other hand.
  • AP, lateral, and mortise radiographic views of the ankle are obtained.
    • Rule out fracture, OCD of talus, or arthritic changes.
  • CT is indicated if occult fracture or tarsal coalition is suspected.
  • MRI:
    • Rarely needed for acute ankle sprains
    • Can be indicated if concomitant tendon tear is suspected
Differential Diagnosis (5)
  • Fibular fracture
  • Osteochondral fracture of the talar dome
  • Peroneal tendon subluxation
  • Congenital tarsal coalition
  • Talar fracture
  • Calcaneal fracture
General Measures (1,4)
  • RICE protocol
  • Partial weightbearing with crutches in the acute phase (first 3–7 days), which is advanced as tolerated to full weightbearing
  • Stirrup ankle brace to facilitate early ambulation
  • NSAIDs may help with pain.
  • Gentle active ROM as tolerated is advised.
  • For severe sprains, consider a formal strengthening and proprioception retraining program with physical therapy (4).
  • Activity modification (rest, sports restriction) until strength returns
Special Therapy
Physical Therapy
ROM, strengthening exercises, and proprioceptive retraining are indicated (4).


Medication (Drugs)
First Line
NSAIDs and analgesics can be used for severe sprains, but they usually are not necessary.
  • Surgical repair of acute ankle ligament tear is rarely indicated (4).
    • Primary repair of ATFL and CFL (6)
  • Surgery may be indicated for patients with recurrent instability.
    • In such patients, repair of the lateral
      ankle ligaments or reconstruction with part of the peroneus brevis
      tendon usually is successful.
The prognosis, which depends on injury severity, is excellent for most patients.
  • OCD
  • Recurrent sprains
Patient Monitoring
  • Patients should show full strength and ROM before returning to sports.
  • Functional bracing or taping during return to athletics may help prevent recurrence.
1. Clanton
TO, Schon LC. Athletic injuries to the soft tissues of the foot and
ankle. In: Mann RA, Coughlin MJ, eds. Surgery of the Foot and Ankle,
6th ed. St. Louis: Mosby-Year Book Inc, 1993:1095–1224.
2. Brostrom L. Sprained ankles. I. Anatomic lesions in recent sprains. Acta Chir Scand 1964;128: 483–495.
3. Leach
RE, Schepsis AA. Acute injuries to ligaments of the ankle. In: Evarts
CM, ed. Surgery of the Musculoskeletal System, 2nd ed. New
York:Churchill Livingstone, 1990:3887–3913.
4. Kannus
P, Renstrom P. Treatment for acute tears of the lateral ligaments of
the ankle. Operation, cast, or early controlled mobilization. J Bone Joint Surg 1991;73A:305–312.
5. Renstrom PAFH. Persistently painful sprained ankle. J Am Acad Orthop Surg 1994;2:270–280.
6. Brostrom L. Sprained ankles. V. Treatment and prognosis in recent ligament ruptures. Acta Chir Scand 1966;132:537–550.
Additional Reading
Chabra A, Katolik LI, Pavlovich R, et al. Sports medicine. Section 3. Leg, foot, and ankle. In: Miller MD, ed. Review of Orthopaedics, 4th ed. Philadelphia: WB Saunders Co, 2004:228–231.
Thacker SB, Stroup DF, Branche CM, et al. The prevention of ankle sprains in sports. A systematic review of the literature. Am J Sports Med 1999;27:753–760.
845.0 Ankle sprain
Patient Teaching
An appropriate return to activity plan is determined based on the severity of the ankle sprain.
Proprioceptive training has been shown to decrease recurrent sprains.
Q: Which ligaments are involved and in what sequence in a lateral ankle sprain?
A: A lateral ankle sprain injures the following, in order: anterolateral joint capsule, ATFL, and occasionally the CFL.

Q: What condition must be ruled out in an adolescent patient with a rigid flatfoot and recurrent ankle sprains?
A: Tarsal coalition.
Which ligament provides primary static restraint to inversion injury with the ankle plantarflexed?
  • ATFL.
What are appropriate initial treatments for acute ankle sprain?
  • RICE protocol, stirrup brace, early ambulation, and ROM exercises.

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