LATERAL ANKLE INSTABILITY | SOUTH TEXAS FOOT SPECIALIST
Chronic ankle instability or lateral ankle instability is a condition in which the ankle feels weak, gives way or sprains easily.
There are three ligaments on the outside of the ankle joint that prevent the ankle from turning:
Anterior talofibular ligament (ATF) – This ligament is the first line of defense for ankle sprains. It is on the front of the ankle, starting on the fibula, the bone on the outside of the ankle and running forward to attach to the talus, the bone on the foot below the ankle. Basketball players, coming down from a layup may catch the front of the foot on the ground or an opposing player's shoe causing the ankle to roll over and under. This ligament can tear suddenly with a bad sprain or gradually with multiple sprains.
Posterior talofibular ligament (PTF) – This ligament is in back of (posterior to) the anterior talofibular ligament. It may tear after the ATF ligament tears in a more serious sprain. If the anterior talofibular ligament was torn previously, the PTF is more exposed to damage.
Calcaneofibular ligament (CFL) – The CFL runs from the outside of the ankle bone (fibula) to the heel bone. It is the thickest of the three ligaments.
Symptoms of lateral ankle instability may include:
A feeling of instability or wobbliness of the ankle. Patients may feel that they do not have a solid base of support.
Repeated spraining or turning of the ankle especially when on uneven ground. We are often told that such ankles can give way when stepping on a rock or similar object and one need be carefully how they step.
Persistent swelling or soreness on the outside of the ankle. One often sees a “pocket” of swelling or fluid on the outside of the ankle. That is termed, more accurately, “effusion,” which is a leakage of joint fluid from the ankle joint into the surrounding tissues. The damaged ligaments on the outside of the ankle joint allow ankle joint fluid to escape.
Why lateral ankle instability needs to be treated
Ankles that roll or sprain easily can lead to further injuries such as ankle fractures, worse sprains ankle joint arthritis or falls.
Occupation considerations – a fireman who goes up and down ladders, a roofer or professional athlete require a stable ankle more than someone with a desk job.
Fall prevention – falls are a major cause of injury in the elderly leading to more significant injury such as hip fractures.
How lateral ankle instability is treated
Ankle braces – there are ankle braces used for the treatment of ankle sprains but a different type of brace used to prevent sprains.
Physical therapy and exercises – This treatment falls into two categories:
Ankle strengthening exercises – such exercises focus on strengthening of the peroneal muscles, peroneus longus and peroneus brevis which are muscles that run down the outside of the leg, ankle and foot. Strong peroneal muscles can help prevent ankle sprains but do not make up completely for damaged ligaments.
Proprioceptive exercises – The term “proprioception” refers to ones ability to percieve the position of body parts at any given time. For example, if the ankle is about to turn, the body senses this and automatically starts contracting the peroneal muscles to prevent a sprain. The faster the body does this, the more likely the ankle sprain will be prevented. Proprioception exercises are designed to “speed” the body's ability to respond to motion that can cause injury.
Foot orthotics and ankle foot orthotics – Prescription foot orthotics can be designed with feature such as lateral flanges to keep the foot from rolling outward. Most store bought inserts or “orthotics” are essentially arch supports. Arch supports need be used cautiously in patients with lateral ankle instability because the act of lifting the arch makes its easier to sprain the ankle.
Ankle foot orthotics are foot orthotics which have sections that come up the ankle to provide the additional needed support. Many such devices are sport specific. For example, an AFO designed for soccer players may have a shin guard added.
Surgical treatment of lateral ankle instability
The ligament most affected in lateral ankle instability is the anterior talofibular ligament (ATFL). It is possible, in many cases, for the podiatric surgeon to simply sew up the ends of the ligament, restoring strength. Use of sonography or diagnostic ultrasound allows us to determine the condition of the ligament to see if such a repair is possible ahead of time.
The ATFL is often frayed or too weak to be repaired but there are a number of techniques to reinforce the ligament either using suture or a graft material. Repair of the ATFL is often termed a “Brostrom” procedure. There are various modifications of the Brostrom procedure such as the Brostrom-Gould procedure in which tissue from the surrounding joint capsule is brought in to reinforce the ligament. Additonally, a number of manufacturers have created products to enhance and strengthen the repair.
For example: Arthrex has developed the 2.4 mm Mini Bio-SutureTaks and the 2.5 mm Bio-PushLock Anchors offering a strong knotless fixation for the Modified Brostrom-Gould Technique.
For more information on Lateral Ankle Instability in the San Antonio, TX area, call Ed Davis, DPM, FACFAS at (210) 490-3668 today!