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Sprain, Ankle

BASICS

  • Definition:
    Most common ankle injury in both athletic and general populations. Three types:
    • Lateral (LAS): Most common; involves ATFL, CFL, PTFL.
    • Medial (MAS): Deltoid ligament injury.
    • Syndesmotic ("high ankle sprain"): Involves syndesmosis between distal tibia and fibula.
  • Classification by severity:
    • Grade I: Mild stretch/microscopic tear.
    • Grade II: Incomplete tear.
    • Grade III: Complete ligament tear.

EPIDEMIOLOGY

  • Incidence:
    Very common; ~50% during sports (especially basketball, volleyball, tennis, football, soccer).
    High ankle sprains: Most in football, wrestling, soccer.
  • Prevalence:
    11–17% of high school/collegiate sports injuries.

ETIOLOGY & PATHOPHYSIOLOGY

  • LAS: Inversion + plantar flexion.
  • MAS: Forced eversion + dorsiflexion.
  • Syndesmotic: Eversion stress/extreme dorsiflexion + internal tibial rotation.

RISK FACTORS

  • Intrinsic: Limited dorsiflexion, reduced proprioception, poor balance, low BMI, anatomic variants.
  • Extrinsic: Court/field sports, high heels, prior ankle sprain, poor conditioning.
  • Children: Greater risk of physeal (growth plate) injury vs ligament tear.

COMMONLY ASSOCIATED CONDITIONS

  • Contusions, fractures (fibular head, 5th metatarsal base, Salter-Harris), dislocations.

DIAGNOSIS

HISTORY

  • Mechanism: inversion vs eversion.
  • Popping/snapping, immediate pain/swelling, difficulty bearing weight.
  • Prior injuries, location of pain.

PHYSICAL EXAM

  • Compare with uninjured ankle: swelling, bruising, laxity.
  • Palpate ATFL, CFL, PTFL, deltoid ligament, malleoli, 5th metatarsal base, navicular, entire fibula.
  • ROM and strength in all directions.
  • Special tests:
    • Anterior drawer: ATFL laxity.
    • Talar tilt: CFL (inversion), deltoid (eversion).
    • Squeeze test: Syndesmotic injury.
    • Dorsiflexion/external rotation test: Syndesmotic injury.
  • Grading:
    • Grade I: Mild, no laxity, full ambulation.
    • Grade II: Moderate, mild laxity, painful weight bearing.
    • Grade III: Severe, no endpoint, instability, unable to ambulate.

DIFFERENTIAL DIAGNOSIS

  • Tendon injury/tear
  • Fracture/dislocation
  • Hindfoot/midfoot injuries
  • Nerve injury
  • Contusion

DIAGNOSTIC TESTS

  • Ottawa ankle rules: Indicate need for x-rays.
  • Pain in malleolar zone + inability to bear weight (≥4 steps)
  • Bony tenderness: distal malleoli, navicular, base of 5th metatarsal
  • Imaging: AP/lateral/mortise ankle x-rays if indicated; US (dynamic, operator-dependent); MRI (rarely needed).
  • If no improvement in 6–8 weeks: Consider CT, MRI, US.

TREATMENT

GENERAL MEASURES

  • Most grades I–III lateral sprains: conservative management.
  • RICE (Rest, Ice, Compression, Elevation) during acute phase.
  • Early mobilization/functional bracing (lace-up brace > immobilization).
  • Short immobilization (<10 days) if severe pain/swelling; longer for syndesmotic injuries.
  • Manual therapy for ROM, pain, and function.
  • Neuromuscular/proprioceptive training within first week to reduce reinjury risk.

MEDICATION

  • NSAIDs: Acute phase for pain/swelling (judicious use; topical preferred).
  • Acetaminophen: Alternative or adjunct (max 3,250 mg/day).
  • Opioids: Rare; for severe pain <5 days only.
  • PRP: Limited short-term benefit for pain/function in LAS; unclear long-term benefit.

REFERRAL

  • Fracture (malleolar/talar dome)
  • Syndesmotic sprain
  • Dislocation/subluxation
  • Tendon rupture
  • Persistent instability or uncertain diagnosis

ADDITIONAL THERAPIES

  • Physical therapy: Initiate early post-acute phase to improve ROM, strength, proprioception.
  • Rehabilitation: Critical for preventing chronic instability and speeding healing.
  • Return to play:
    • Grade I: 1–2 weeks
    • Grade II: 2–3 weeks
    • Grade III: ~4 weeks
    • Syndesmotic: 8–9 weeks

SURGERY

  • Reserved for recurrent or complex sprains and failed conservative therapy.
  • Anatomic repair/reconstruction for chronic instability.

ONGOING CARE

  • Follow-up: Orthoses for moderate/severe sprains during sports (≥6 months).
  • Monitor: If symptoms persist >6–8 weeks, repeat exam and consider imaging.

PATIENT EDUCATION

  • Crutch training if needed.
  • Instruction on brace/taping and exercises (alphabet trace, towel grab).
  • Importance of rehab and prevention strategies.

PROGNOSIS

  • Early PT/mobilization + bracing = faster return to activity.
  • Poorer prognosis with higher grade, older age, initial non-weight-bearing.
  • Ligamentous strength recovers over months.

COMPLICATIONS

  • Joint instability, recurrent sprains, cartilage damage, chronic pain/swelling (5–33% at 1 year), degenerative changes.

ICD-10

  • S96.919A: Strain of unspecified muscle/tendon at ankle/foot, unspecified foot, initial encounter
  • S93.499A: Sprain of other ligament of unspecified ankle, initial encounter
  • S93.419A: Sprain of calcaneofibular ligament of unspecified ankle, initial encounter

CLINICAL PEARLS

  • Kids: Higher risk of physeal injury than sprain.
  • Proprioceptive training helps prevent recurrence.
  • Functional rehab > immobilization for faster recovery.
  • Poorly rehabbed ankles risk chronic instability.
  • Failure to improve by 6–8 weeks? Consider advanced imaging.