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Sprain, Ankle
Shane L. Larson, MD
image BASICS
DESCRIPTION
The most common cause of ankle injury comprising a significant proportion of sports injuries:
  • Types of ankle sprains: lateral, medial, and syndesmotic (or high ankle sprain)
    • Lateral ankle sprains are the most common, accounting for 85% of all ankle sprains:
      • In lateral ankle sprains, the anterior talofibular ligament (ATFL) is most likely to be injured.
      • The calcaneofibular ligament (CFL) is the second most likely ligament to be injured.
      • The posterior talofibular ligament (PTFL) is the least likely to be injured.
    • Medial ankle sprains (5-10%) result from an injury to the deltoid ligament.
    • Syndesmotic (or high ankle) injuries account for 5-10% of ankle sprains.
      • The syndesmosis between the distal tibia and distal fibula bones consists of the anterior, posterior, and transverse tibiofibular ligaments and the interosseous ligament and interosseous membrane.
  • Ankle sprains are classified according to the degree of ligamentous disruption:
    • Grade I: mild stretching of a ligament with possible microscopic tears
    • Grade II: incomplete tear of a ligament
    • Grade III: complete ligament tear
Geriatric Considerations
Increased risk of fracture in patients with preexisting bone weakness (osteoporosis/osteopenia)
Pediatric Considerations
  • Increased risk of physeal injuries instead of ligament sprain because ligaments have greater tensile strength than physes
  • Inversion ankle injuries in children may have a concomitant fibular physeal injury (Salter Harris type I or higher fracture).
  • Consider tarsal coalition with recurrent ankle sprains.
EPIDEMIOLOGY
Incidence
  • Peak incidence in children (0 to 12 years old), then adolescents (13 to 17 years old), and finally adults (≥18 years old) (1)
  • 1/2 of all ankle sprains are sports-related; highest incidence in indoor/court sports (basketball, volleyball, tennis), followed by football and soccer (2)
  • Most common sports injury
  • More common in males age <30 years and females >30 years old
Prevalence
  • 25% of sports injuries in the United States
  • 75% of all ankle injuries are sprains.
ETIOLOGY AND PATHOPHYSIOLOGY
  • Lateral ankle sprains result from an inversion force with the ankle in plantar flexion.
  • Medial ankle sprains are due to forced eversion while the foot is in dorsiflexion.
  • Syndesmotic sprains result from eversion stress/extreme dorsiflexion along with internal rotation of tibia.
RISK FACTORS
  • The greatest risk factor is a prior history of an ankle sprain (3-34% recurrence rate).
  • Postural instability, gait alterations
  • Joint laxity and decreased proprioception are not risk factors.
GENERAL PREVENTION
  • Improve overall physical conditioning:
    • Training in agility and flexibility
    • Single-leg balancing
    • Proprioceptive training (3)
  • Taping and bracing may help prevent primary injury in selected sports (i.e., volleyball, basketball, football) or reinjury (4). Taping and bracing do not reduce sprain severity.
COMMONLY ASSOCIATED CONDITIONS
  • Contusions
  • Fractures
    • Fibular head fracture/dislocation (Maisonneuve)
    • Fracture of the base of the 5th metatarsal
    • Distal fibula physeal fracture (includes Salter-Harris fractures in pediatric patients; most common type of pediatric ankle fracture)
image DIAGNOSIS
PHYSICAL EXAM
  • Timing: Initial assessment for laxity may be difficult due to pain, swelling, and muscle spasm. Repeat exam ˜5 days after injury may improve sensitivity.
  • Compare to uninjured ankle for swelling, ecchymosis, weakness, and laxity
  • Neurovascular exam
  • Palpate ATFL, CFL, PTFL, and deltoid ligament for tenderness.
  • Palpate lateral and medial malleolus, base of 5th metatarsal, navicular, and entire fibula.
    • High ankle sprain associated with fracture of proximal fibula
  • Grade I sprain: mild swelling and pain; no laxity; able to bear weight/ambulate without pain
  • Grade II sprain: moderate swelling and pain; mild laxity with firm end point noted; weight bearing/ambulation painful
  • Grade III sprain: severe swelling, pain, and bruising; laxity with no end point; significant instability and loss of function/motion; unable to bear weight/ambulate
    • Swelling less sensitive for grade of tear in pediatric patient
  • Special tests:
    • Anterior drawer test to check for ATFL laxity
    • Talar tilt test to check laxity in CFL (with inversion) or deltoid ligament (eversion)
    • Squeeze test: Compress tibia and fibula midcalf to check for syndesmotic injury; sensitivity 30%, specificity 93.5%.
    • Dorsiflexion/external rotation test: Positive test is pain at syndesmosis with rotation; sensitivity 20%, specificity 85%.
DIFFERENTIAL DIAGNOSIS
  • Tendon injury
    • Tendinopathy/tendon tear
  • Fracture and/or dislocation of the ankle/foot
  • Hindfoot/midfoot injuries
  • Nerve injury
  • Contusion
DIAGNOSTIC TESTS & INTERPRETATION
  • Ottawa Ankle Rules (nearly 100% sensitive, 30-50% specific) determine need for radiographs to rule out ankle fractures (patient must be 18 to 55 years; certain patients, e.g., diabetics with diminished sensation, may still need radiographs):
    • Pain in malleolar zone
    • Inability to bear weight (walk ≥4 steps) immediately and in the exam room
    • Bony tenderness at tip/posterior edge of the lateral/medial malleolus
      • Note: Ottawa rule for foot imaging series (reported pain in the midfoot zone AND pain with palpation of navicular or base of 5th metatarsal, OR inability to bear weight immediately and in the ER/office)
    • Although Ottawa rules are highly sensitive, they should not overrule clinical judgment.
  • If radiographs are indicated, obtain anteroposterior, lateral, and mortise views of the ankle.
    • Small avulsion fractures are associated with grade III sprains.
  • Consider CT if radiographs are negative but occult fracture is suspected clinically.
  • MRI is the gold standard for soft tissue imaging but is expensive and rarely necessary.
    • Syndesmotic ankle sprains: MRI is more sensitive.
  • US is a good second line imaging option with a sensitivity comparable to MRI.
Follow-Up Tests & Special Considerations
If patient condition does not improve in 6 to 8 weeks, consider CT, MRI, or US.
image TREATMENT
GENERAL MEASURES
  • Most grade I, II, and III lateral ankle sprains can be managed conservatively.
  • Conservative therapy: PRICE (protection, relative rest, ice, compression, elevation)
  • Protection/compression: For grade I/II sprains, laceup bracing is superior to air-filled/gel-filled ankle brace, which is superior to elastic bandage/taping to provide support and decrease swelling.
    • Note: The combination of air-filled brace and compression wrap is superior to each individual for return to preinjury joint function at 10 days and 1 month for grades I and II sprains (5)[A].
    • P.983

    • Grade III sprains should have short-term immobilization (10 days) with below-the-knee cast, followed by a semirigid brace (air cast). If a patient refuses casting, a 10-day period of strict non-weight-bearing with air cast splint and elastic bandage is a comparable alternative if non-weight-bearing is maintained.
  • Rest: Initially, activity as tolerated. Early mobilization and physical therapy speed recovery/reduce pain:
    • Weight bearing, as tolerated
    • Consider crutches if unable to bear weight.
    • Exercises should be initiated as early as tolerated and limited to pain-free range of motion.
    • Patients can start mobilization by tracing the alphabet with the foot in the air.
    • Resistance exercises with an elastic band
  • Ice: Ice for first 3 to 7 days for pain reduction and decrease recovery time
  • Elevation: Elevate ankle to decrease swelling.
MEDICATION
  • NSAIDs: preferably oral; topical forms (e.g., diclofenac 1% gel) may be used to minimize GI side effects. PRN NSAID dosing has similar outcomes to scheduled dosing with improved safety profile.
    • Example: Naproxen 500 mg BID PRN
  • Acetaminophen 650 mg q4-6h (max outpatient therapy dose: 3,250 mg/day)
  • Opioids if severe pain
ISSUES FOR REFERRAL
  • Malleolar/talar dome fracture
  • Syndesmotic sprain
  • Dislocation/subluxation
  • Tendon rupture
  • Ongoing instability
  • Uncertain diagnosis
ADDITIONAL THERAPIES
Physical therapy:
  • After the acute phase of the injury, patients with grade II or III sprain should start physical therapy as soon as possible to increase range of motion, strength, flexibility, and improve proprioceptive balance (wobble board/ankle disk).
  • Functional rehabilitation prevents chronic instability and speeds healing.
  • Athletes should undergo sports-specific rehabilitation before returning to play.
SURGERY/OTHER PROCEDURES
  • Surgery is typically reserved for treatment of complicated recurrent sprains and certain syndesmotic sprains.
  • Patients with chronic ankle instability who fail functional rehabilitation or with poor tissue quality may need anatomic repair/reconstructive surgery.
image ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
  • After an ankle sprain, ankle-stabilizing orthoses (air stirrup braces, lace-up supports, athletic taping, etc.) should be worn for high-risk sports to prevent future ankle sprains.
  • Moderate and severe sprains require ankle orthoses for ≥6 months during sports participation.
  • Gradual return to play for athletes with a grade I lateral ankle sprain can generally be accomplished in 1 to 2 weeks; grade II sprain return to play time is 2 to 3 weeks; grade III sprain is approximately 4 weeks.
  • Syndesmotic sprains take longer (approx. 8 to 9 weeks) to heal than lateral ankle sprains.
Patient Monitoring
If athletes continue to have symptoms when they return to play or if a patient has pain for 6 to 8 weeks after injury, repeat examination and imaging.
PATIENT EDUCATION
  • Crutch training
  • Provide training on proper use of elastic bandages, brace, and/or orthoses
  • Demonstrate mobilization exercises (alphabet trace, towel grab).
PROGNOSIS
  • Earlier physical therapy and mobilization with bracing allows for faster return to daily living and/or sports.
  • Higher grade sprains, older patient age, and initial non-weight-bearing status have poorer prognosis and longer recovery.
  • Ligamentous strength does not return for months after the injury.
REFERENCES
1. Doherty C, Delahunt E, Caulfield B, et al. The incidence and prevalence of ankle sprain injury: a systematic review and meta-analysis of prospective epidemiological studies. Sports Med. 2014;44(1):123-140.
2. Waterman BR, Owens BD, Davey S, et al. The epidemiology of ankle sprains in the United States. J Bone Joint Surg Am. 2010;92(13):2279-2284.
3. McGuine TA, Keene JS. The effect of a balance training program on the risk of ankle sprains in high school athletes. Am J Sports Med. 2006;34(7):1103-1111.
4. Pedowitz DI, Reddy S, Parekh SG, et al. Prophylactic bracing decreases ankle injuries in collegiate female volleyball players. Am J Sports Med. 2008;36(2):324-327.
5. Beynnon BD, Renström PA, Haugh L, et al. A prospective, randomized clinical investigation of the treatment of first-time ankle sprains. Am J Sports Med. 2006;34(9):1401-1412.
Additional Reading
&NA;
  • Bleakley CM, O'Connor SR, Tully MA, et al. Effect of accelerated rehabilitation on function after ankle sprain: randomised controlled trial. BMJ. 2010;340:c1964.
  • Farwell KE, Powden CJ, Powell MR, et al. The effectiveness of prophylactic ankle braces in reducing the incidence of acute ankle injuries in adolescent athletes: a critically appraised topic. J Sport Rehabil. 2013;22(2):137-142.
  • Hiller CE, Nightingale EJ, Lin CW, et al. Characteristics of people with recurrent ankle sprains: a systematic review with meta-analysis. Br J Sports Med. 2011;45(8):660-672.
  • Kerkhoffs GM, van den Bekerom M, Elders LA, et al. Diagnosis, treatment and prevention of ankle sprains: an evidence-based clinical guideline. Br J Sports Med. 2012;46(12):854-860.
  • Massey T, Derry S, Moore RA, et al. Topical NSAIDs for acute pain in adults. Cochrane Database Syst Rev. 2010;(6):CD007402.
  • Pedowitz DI, Reddy S, Parkeh SG, et al. Prophylactic bracing decreases ankle injuries in collegiate female volleyball players. Am J Sports Med. 2008;32(2):324-327.
  • Raymond J, Nicholson LL, Hiller CE, et al. The effect of ankle taping or bracing on proprioception in functional ankle instability: a systematic review and meta-analysis. J Sci Med Sport. 2012;15(5):386-392.
Codes
&NA;
ICD10
  • S96.919A Strain of unsp msl/tnd at ank/ft level, unsp foot, init
  • S93.499A Sprain of other ligament of unspecified ankle, init encntr
  • S93.419A Sprain of calcaneofibular ligament of unsp ankle, init
Clinical Pearls
&NA;
  • Children are at an increased risk of physeal injuries because ligaments are stronger than physes.
  • Conditioning, including proprioceptive training, before participating in sports and throughout the season helps to prevent ankle sprains.
  • Functional rehabilitation, rather than total immobilization, is recommended for quicker return to sport and work.
  • If patient's condition is not improving in 6 to 8 weeks, consider advanced imaging with CT, MRI, or US.