Ankle sprain & its clinical significance

What is Ankle Sprain?

An Ankle sprain is actually an injury to the ligaments of the ankle joint, which are elastic, band-like structures that hold the bones of the ankle joint together and prevent excess turning and twisting of the joint. In normal movement, the ligaments can stretch slightly and then retract back to their normal shape and size. A sprain results when the ligaments of the ankle have been stretched beyond their limits. In severe sprains, the ligaments may be partially or completely torn.

The ankle joint is fairly unstable and largely depends on the ligaments for its stability. The ankle sprain is of two types-

• 1-Pronation or eversion type.
• 2-Supination and inversion type.

  Mechanism of Ankle sprain

  The ligament is injured when the plantar flexed foot is suddenly forced into inversion, which may cause rupture, sprain of lateral ligament.
  The injury is common in sports activity. It is quite common when a person slips off or walk on uneven surfaces. The foot is forced into inversion and plantar flexion which results in external rotation of tibia. The site of injury is generally the centre and distal attachments of anterior and middle band of the ligament.
  When sudden inversion force occurs with the ankle in mid position of dorsi and plantar flexion, the injury involves the calcaneo-fibular ligament (CFL). Whereas when the excessive inversion-adduction movement is associated with forced plantar flexion, the injury commonly involves anterior talo-fibular ligament (ATFL). This can be identified by the site of pain and tenderness. Pain and tenderness over talus indicates injury to talo-fibular ligament while the same over calcaneus indicates the involvement of calcaneo-fibular ligament. This identification is necessary for prompt treatment 

  Sprained Ankle Symptoms

  • History- The patient describes 'going over' at the ankle.
  • Pain- There is sharp pain just below and anterior to the lateral malleolus. Passive stretching and weight bearing increase the pain. Pain because the nerves are more sensitive: The joint hurts and may throb.
  • Swelling- When an ankle is injured with a sprain, tissue injury and the resulting inflammation occur. Blood vessels become "leaky" and allow fluid to ooze into the soft tissue surrounding the joint. White blood cells responsible for inflammation migrate to the area, and blood flow increases as well. This is present from the lateral border of  tendo-achilles, over the lateral malleolus along the dorsum of the foot. In severe injuries, swelling may spread to the dorsum of the toe and up to the leg.
  • Bruising- This appears under the lateral malleolus and over the dorsum of the foot.
  • Loss of function- All weight bearing is painful, so the patient cannot run and has a gait with a very short stance phase on the affected foot.