Abstract
Ankle sprains have been shown to be the most common sports related injury. Ankle sprain may be classified into low ankle sprain or high ankle sprain.
Low ankle sprain is a result of lateral ligament disruption. It accounts for approximately 25% of all sports related injuries. The ankle lateral ligament complex consists of three important structures, namely the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL) and posterior talofibular ligament (PTFL). The ATFL is the weakest and most easily injured of these ligaments. It is often described as a thickening of the anterolateral ankle capsule. The ATFL sits in a vertical alignment when the ankle is plantarflexed and thus is the main stabiliser against an inversion stress. T he CFL is extracapsular and spans both the tibiotalar and talocalcaneal joints. The CFL is vertical when the ankle is dorsiflexed. An isolated injury to the CFL is uncommon.
Early diagnosis, functional management and rehabilitation are the keys to preventing chronic ankle instability following a lateral ligament injury. Surgery does not play a major role in the management of acute ligament ruptures. Despite this up to 20% of patients will develop chronic instability and pain with activities of daily living and sport especially on uneven terrain. Anatomic reconstruction for this group of patients is associated with 90% good to excellent results. It is important that surgery is followed by functional rehabilitation. One of the aims of surgery in patients with recurrent instability is to prevent the development of ankle arthritis. It should be noted that the results of surgical reconstruction are less predictable in patients with greater than 10 year history of instability. Careful assessment of the patient with chronic instability is required to exclude other associated conditions such as cavovarus deformity or generalised ligamentous laxity as these conditions would need to be addressed in order to obtain a successful outcome.
High ankle sprain is the result of injury to the syndesmotic ligaments. The distal tibiofibular joint is comprised of the tibia and fibula, which are connected by anterior inferior tibiofibular ligament, interosseous ligament and the posterior inferior tibiofibular ligament (superficial and deep components). The mechanism of injury is external rotation and hyperdorsiflexion. High index of suspicion is required as syndesmotic injuries can occur in association of low ankle sprains. The clinical tests used in diagnosing syndesmotic injuries (external rotation, squeeze, fibular translation and cotton) do not have a high predictive value. It is important to exclude a high fibular fracture. Plain radiographs are required. If the radiograph is normal then MRI scan is highly accurate in detecting the syndesmotic disruption. Functional rehabilitation is required in patients with stable injuries. Syndesmotic injuries are often associated with a prolonged recovery time. Accurate reduction and operative stabilisation is associated with the best functional outcome in patients with an unstable syndesmotic injury. Stabilisation has traditionally been with screw fixation. Suture button syndesmosis fixation is an alternative. Early short-term reviews show this alternate technique has improved patient outcomes and faster rehabilitation without the need for implant removal.
