Summary

The Acute Lateral Ankle Sprain is the single most common musculoskeletal injury in the active population. It involves the stretching or tearing of the Lateral Ligament Complex (ATFL, CFL, PTFL) due to a sudden inversion force on a plantarflexed foot (e.g., landing on an opponent's foot, stepping off a curb). While often trivialized, mismanagement leads to Chronic Ankle Instability in 20-30% of patients. Treatment has shifted decisively from rigid immunization (casts) to Functional Rehabilitation (protection + early motion), which accelerates return to sport and ligament tensile strength. [1,2,3]

Key Facts

• The Ligaments:
  1. ATFL (Anterior Talofibular): The weakest link. Resists inversion in plantarflexion. 1st to tear.
  2. CFL (Calcaneofibular): Resists inversion in neutral/dorsiflexion. 2nd to tear.
  3. PTFL (Posterior Talofibular): The strongest. Resists rotation. Only tears in frank dislocation.
• Ottawa Ankle Rules: A highly sensitive (98%) clinical decision rule to rule out fractures and reduce unnecessary X-rays. If you are not tender on the bone and can walk 4 steps, you don't need an X-ray.
• Proprioception: The ligaments contain mechanoreceptors. When torn, balance is impaired. Retraining balance (wobble board) is the most critical part of rehab to prevent recurrence.

Clinical Pearls

"It's not just a sprain": Be wary of the "sprained ankle" that doesn't get better. Often it is a missed Talar Dome Lesion (OCD), Peroneal Tendon Tear, or Syndesmosis injury.

"The Egg": Rapid development of a golf-ball sized swelling over the lateral malleolus usually indicates rupture of the ATFL and bleeding from its artery (branch of peroneal).

"Cast is Bad": Prolonged casting (>10 days) for a simple sprain causes stiffness, atrophy, and delays recovery. The ligaments heal stronger when stressed (Wolff's Law for soft tissue).

                 INVERSION INJURY
                        ↓
               OTTAWA RULES POSITIVE?
            ┌───────────┴───────────┐
           YES                     NO
            ↓                       ↓
          X-RAY                NO X-RAY
      (Rule out #)           (Clinical Dx)
            ↓                       ↓
      FRACTURE?               GRADE OF SPRAIN?
     ┌──────┴──────┐       ┌────────┴────────┐
    YES           NO     I/II               III
   (Treat #)       ↓       ↓                 ↓
              FUNCTIONAL REHAB           CAM BOOT
             (Brace + Motion)         (Short term 10d)
                   ↓                         ↓
              PT / BALANCE             FUNCTIONAL REHAB

Phase 1: Protection (Week 0-1)

• M.I.C.E.: Motion, Ice, Compression, Elevation.
• Brace: Stirrup brace (AirCast) or Lace-up brace to prevent inversion.
• Weight Bearing: Weight bear as tolerated (crutches if needed, but wean quickly).
• Motion: Active dorsifflexion/plantarflexion (ABC exercises). Avoid Inversion.

Phase 2: Strengthening (Week 2-4)

• Isometrics (Peroneals).
• Calf raises.
• Cycling.

Phase 3: Proprioception (Week 4+)

• Critical Phase.
• Wobble board.
• Single leg stance (eyes closed).
• Sport specific drills.

Acute Repair?

• Generally Contraindicated.
• Multiple Level 1 studies show no long-term benefit of acute repair vs functional rehab for Grade III sprains. Rehab works.
• Exception: High-level professional athletes (sometimes) or gross dislocation.

Functional Rehab vs Cast

• Lamb et al (Lancet): Large RCT. Severe sprains treated with functional bracing had faster return to work/sport and less stiffness than those treated with cast immobilization. Functional rehab is the gold standard.

Proprioception

• Hupperets et al: Showed that an 8-week proprioceptive training program reduced the risk of recurrent sprain by 35% in athletes.

The Injury

You have torn the tether (ligament) that stops your ankle rolling outwards. It's like fraying a rope.

The Plan

We are NOT going to put you in a plaster cast. Plaster makes the ankle stiff and weak. We want you to move it.

1. Wear this brace (it stops the rolling but lets you move up and down).
2. Put ice on it.
3. Walk on it as much as pain allows. The more you move it, the faster the swelling goes away.

The Balance

The most important thing is to retrain your balance. Your brain has "forgotten" where your foot is. Use a wobble board or stand on one leg while brushing your teeth.

Q1: What are the Ottawa Ankle Rules? A: A clinical decision rule to exclude fractures. X-ray is indicated only if there is pain in the malleolar zone AND:

1. Bone tenderness at the posterior edge (distal 6cm) of the lateral malleolus OR
2. Bone tenderness at the posterior edge of the medial malleolus OR
3. Inability to bear weight both immediately and in the ED (4 steps).

Q2: Which ligament is injured in a Syndesmosis sprain? A: AITFL (Anterior Inferior Tibiofibular Ligament). It heals much slower than the lateral ligaments.

Q3: Why is proprioceptive training essential? A: Ligaments contain mechanoreceptors. Rupture causes de-afferentation (loss of position sense). Without retraining, the muscles fire too late to prevent the next sprain, leading to functional instability.

Q4: What is the "Maisonneuve Fracture"? A: A proximal fibula fracture associated with a syndesmosis rupture and medial malleolar injury (or deltoid rupture). Always squeeze the proximal calf in ankle injuries.

(End of Topic)