Exploring Surgical Options For Lateral Ankle Instability
Lateral ankle sprains are some of the most common injuries presenting to the podiatric office, especially to the sports medicine focused practice. Although most heal uneventfully with conservative care and physical therapy, chronic ankle instability is not an unusual sequela. This can be frustrating to the patient who is eager to return to his or her physical activity. Recurrent ankle sprains and lingering instability are common reasons for delay in return to activities and may ultimately necessitate surgical intervention.
It is important to differentiate between functional and mechanical ankle instability. Mechanical instability results from a true disruption of one or more of the lateral ankle ligaments, usually involving a supinatory torque around the ankle.1 Functional instability refers to the feeling of the ankle “giving out” or the patient suffering from multiple ankle sprains without a frank injury to the ligamentous structures. The patient with a functionally unstable ankle will have a negative talar tilt and anterior drawer test. To complicate matters further, a mechanically unstable ankle does not necessarily result in a functionally unstable ankle.1
In looking at 117 functionally unstable ankles, Vaes and his colleagues found mechanical instability in only 41 ankles.2 If the sensorimotor control system of the ankle remains intact despite the injury to the ligaments, a patient may not experience the instability usually associated with an ankle sprain.1 When the instability becomes severe enough, surgery is an excellent treatment option with reproducible results.
Keys To Performing The Brostrom Gould Procedure
One of the most tried and true surgical procedures for chronic lateral ankle instability has been the Brostrom-Gould procedure. Generally, one makes a curvilinear incision along the distal aspect of the fibula. Often, injury to the peroneal tendons necessitates extension of the incision up the posterior aspect of the fibula for examination and possible repair of the tendons. Identify the peroneal sheath and incise it to retract the peroneals in order to gain visualization to the calcaneofibular ligament. Then incise the extensor retinaculum to reveal the attenuated or torn anterior talofibular ligament. Reflect the ligament off the distal fibula and reef this ligament up with FiberWire (Arthrex) or an equivalent suture material. Suture anchors may augment the repair.
Cho and coworkers compared postoperative success of the modified Brostrom procedure using one versus two suture anchors.3 They found that both options provided an effective means of repair with little difference in either clinical or subjective outcomes. The study did reveal slightly more reduction in the talar tilt test postoperatively in the double anchor group.
If an injury to the calcaneofibular ligament is also apparent, one can include this in the repair. Advance the extensor retinaculum proximally over the repaired ligament. At the University Foot and Ankle Institute, our preferred method of ligament repair is inserting two suture anchors into the fibula and repairing the ligaments with FiberWire suture. We then pass the sutures through another PushLock Anchor (Arthrex) and secure them slightly more proximally into the fibula for added security.
Some manufacturers are now developing systems that further augment the repair of the ligaments. For example, the InternalBrace™ system (Arthrex) has recently become a popular method by which to add strength to the ligament repair. This system uses a thick band-like composition of FiberWire, called FiberTape (Arthrex), in conjunction with both an anchor in the fibula and in the talus to recreate the anatomy of the anterior talofibular ligament. Further controlled studies are necessary to test the true benefit of this system but anecdotal reports have been promising, especially in regard to earlier return to rehab and activity.