Lateral Ankle Sprain: Why is it so recurrent?

Lateral ankle sprain is one of the most common sites for acute musculoskeletal injuries accounting for 75% of ankle injuries. More than 25,000 ankle sprains occur each day in the United States. Lateral ankle sprains are the most common injury; from both competitive and recreational sports to even our day-to-day life. Yet they are so often mistreated or not treated at all. The biggest consequence of this neglect is a recurrent ankle sprain due to weakness of the ankle muscles leading to an unstable joint.

Anatomy

The lateral aspect of the ankle is generally made up of 3 main ligaments; Anterior Talo-Fibular Ligament (ATFL), Calcaneal Fibular Ligament (CFL) and Posterior Talo-Fibular Ligament (PTFL) (See figure 1). These ligaments help to provide stability to the ankle joint by limiting the inversion movement of the ankle in the dorsiflexion and plantarflexion range. When one or more ligaments are stretched beyond the normal range, a sprain results.

Ankle sprains range in severity from Grade I to Grade III and is useful for more than classifying the severity of the injury; it also directs treatment and prognosis.

Grade	Signs and Symptoms
Grade 1I	Ankle sprains are painful, but they have no increased laxity when compared with the uninjured side. This correlates with mild stretching of the ATFL.
Grade II	Ankle sprains are painful and have an increased laxity on testing. This correlates with a complete tear of the ATFL and a partial tear of the CFL.
Grade III	Ankle sprains are usually painful and have an unstable ankle joint on examination. This correlates with complete ruptures of both the ATFL and CFL.

Mechanism of Lateral ankle sprain

Lateral ankle sprains occur when the foot turns in or out to an abnormal degree relative to the ankle. The most common mechanism of injury in an ankle sprain is a combination of plantarflexion and inversion where the foot is pointing downward and inward, straining the ATFL. Concomitant injury to ATFL and CFL can result in appreciable ankle instability. The PTFL is the strongest of the three ligaments. It is rarely injured in an inversion sprain.

Common causes of ankle sprains include stepping up or down on an uneven surface, particularly when wearing high heels; stepping wrong off a curb or into a hole. In athletics, common causes include landing wrongly after a jump shot and having to make quick directional changes as in tennis, soccer, and netball.

When a person sprains his ankle, he may experience:

• pain or soreness
• swelling
• bruising
• difficulty walking, and/or
• stiffness in the joint

These symptoms may vary in intensity, depending on the severity of the sprain. In persons with previous ankle sprains, pain and swelling may be absent. Instead, they may feel that the ankle is wobbly and unstable when they walk. However, the lack of pain does not mean it is safe to return to activity. The pain can subside fairly quickly but that does not necessarily mean that the injured ligaments have healed. Even if the ligaments have healed, there is still a chance of a recurrent ankle sprain because the ligaments will never be as strong as before to stabilise the ankle joint.

Proper classification of the ankle sprain would improve the management and rehabilitation of the ankle sprain to prevent recurrent sprains.

Management

RICER and Anti-Inflammatory Drugs

Management of the lateral ankle sprain should start the moment it happens. The R.I.C.E.R (Rest, Ice, Compression, Elevation, Review) regime should be enforced within the first 72 hours post-injury. Anti-inflammatory drugs may be recommended. Crutches may be provided for a few days if the ankle is too painful to bear weight.

Literature reviews have been mixed on the use of immobilization versus early functional treatment, as documented in a Cochrane review done in 2002. The mixed reviews were due to the lack of a classification of the ankle sprains and the application of the immobilization. A guideline to the use of immobilization was that in Grade II and III sprains, immobilization of the ankle for about 4 days, with either the air-cast brace or CAM walker, would improve the prognosis and rate of recovery. This should be accompanied together with exercises that prevent joint stiffness and muscle weakening¹.

Proper Rehabilitation

Proper rehabilitation exercise is crucial. This is ensures that new tissues are laid down and aligned properly during the healing phase. Rehabilitation exercise should comprise of four components^2,3:

1. range of motion exercises,
2. progressive muscle-strengthening exercises,
3. proprioceptive/ balance training, and
4. activity-specific training.

Range of motion exercises normally begins on the first session of physiotherapy treatment together with soft tissue mobilization to manage the swelling.

Ultrasound And IFC

Ultrasound and IFC may also be used to manage the swelling and to decrease pain². Compressive bandaging or Kinesiotaping [Figure 2] have been shown to effectively manage the swelling.

Exercises and Stretches

Gentle strengthening exercises and stretches would commence once the pain and swelling are managed. This would normally start in the 2nd-week post-injury. Theraband exercises to strengthen the evertors and functional exercises like calf raises would be done to improve the strength of the ankle. Calf stretches would prevent tightness of the calf muscles arising to the compensation mechanism which prevents the pain.

Proprioceptive training is also an integral part of the rehab at about this time. Balancing on 1 leg with eyes open and eyes closed are taught as home exercises⁴. In the clinic, balancing on unstable surfaces (e.g. wobble board/rocker-board/dura-disc) will be done. Proprioceptive taping may also be done to speed up the recovery process [Figure 3].

Progression of these exercises will go on until about the 4th week. These exercises would be good enough for non-athletes for them to get discharged.

With athletes, sports specific rehab will need to be done and completed before they return to sports. Criteria for them to return to sports varies from sport to sport. A simple functional test to determine whether they are ready to return to sports will be either doing a triple hop test or a 8m hop test, where the results are compared between the injured ankle and the non-injured one.

Conclusion

Prevention of recurrent lateral ankle sprains is possible. However, proper classification is required. This is so that the appropriate management can be administered.

References

1. Kerkhoffs GM, Rowe BH, Assendelft WJ, Kelly K, Struijs PA, van Dijk CN. Immobilisation and functional treatment for acute lateral ankle ligament injuries in adults. Cochrane Database Syst Rev. 2002;(3):CD003762.
2. Kerkhoffs GM, Handoll HH, de Bie R, Rowe BH, Struijs PA. Surgical versus conservative treatment for acute injuries of the lateral ligament complex of the ankle in adults. Cochrane Database Syst Rev. 2007 Apr 18;(2) 
3. Jones MH, Amendola AS. Acute treatment of inversion ankle sprains: immobilization versus functional treatment. Clin Orthop Relat Res. 2007 Feb;455:169-72. 
4. Hupperets MD, Verhagen EA, van Mechelen W. Effect of unsupervised home based proprioceptive training on recurrences of ankle sprain: randomised controlled trial. BMJ. 2009 Jul 9;339