Acute lateral ankle ligament injuries are often also referred to as ankle sprains. It is one of the most common injuries in orthopaedic outpatient emergency departments. According to statistics, ankle injuries account for 15% of all sports injuries, and 85% of these are lateral ligament injuries.
Injury mechanism
When the ankle joint is plantarflexed, it is subjected to extreme inversion and inversion stress, and the talus is inducted and internally rotated within the ankle cavity, and the lateral ligaments are injured. There are three main ligaments in the lateral ankle joint, from anterior to posterior, the anterior talofibular ligament, the heel-fibular ligament and the posterior talofibular ligament. When the foot is plantarflexed or turned inward, the anterior talofibular ligament is the first to be torn by the stress, and when the external force continues, the heel fibular ligament is then torn, and finally the posterior talofibular ligament can be injured.
Because the talus is trapezoidal in the horizontal plane, the widest part of the talus is located in the ankle cavity during plantarflexion, and the ankle joint is the most stable and usually will not be sprained. In plantarflexion, the anterior part of the talus is narrower and there is relative movement within the ankle pits, which can easily cause sprains at this time. A common sprain is an anterior rotation-adduction injury of the ankle joint.
Clinical manifestations
The following manifestations occur after ankle sprain.
1. Swelling of the outer ankle
2. bruising and ecchymosis
3. Localized pain and pressure pain
4. Instability of the ankle joint in the anterior and posterior directions
After acute injury, the patient is unable to walk because of local swelling and pain, and in severe cases, the affected foot cannot stand and bear weight. Ankle sprains are mainly ligament injuries, but severe injuries may be accompanied by intra-articular cartilage injuries and lower tibiofibular joint injuries.
After an acute injury, approximately 20-40% of patients will experience prolonged and recurrent ankle weakness and sprain, especially when walking on uneven ground, and the patient will often feel a loss of control of the ankle joint and inversion will occur. The sprain may or may not be accompanied by painful swelling. Some patients may feel stiffness in the ankle joint. At this point, the patient enters the chronic instability phase. The patient may have either mechanical instability or functional instability.
Diagnosis.
The patient’s medical history, mechanism of injury, and attention to any causative stresses and causative mechanisms that caused the midfoot, lower tibiofibular joint injury, heel fracture, or peroneal tendon dislocation should be asked. Whether this is the patient’s first injury and whether there are any repeated injuries. There is no history of previous foot and ankle disease.
The scope and extent of the injury should be examined by an orthopedic surgeon after a general sprain, noting the presence of any concurrent injuries. If other injuries and fractures cannot be excluded, a frontal and lateral x-ray of the foot and ankle should also be taken.
After ankle sprain, the anterior talofibular ligament is most likely to be injured. When this ligament is injured, there can be obvious swelling and pressure pain on the anterior medial side of the outer ankle, sometimes accompanied by local bruising. The swelling is not limited to the lateral ankle, but may also extend to the anterior, posterior and medial aspects of the ankle joint.
The most widely used clinical classification of ankle ligament injuries is the American Medical Association (AMA) standard classification, which classifies ligament injuries according to the degree of ligament damage as follows
Degree I: Ligamentous tear injury. This means that the ligament is stretched, but not significantly torn. The ankle joint is stable, mildly swollen, and function is largely unaffected.
Grade II: Partial tear of the ligament. There may be mild to moderate instability and ankle function may be affected.
Degree III: Complete rupture of the ligament. There is significant swelling, ecchymosis and instability.
In the case of anterior talofibular ligament rupture, a positive anterior drawer test can be seen on examination. However, it is difficult to perform the test in patients with acute injury and swelling. The anterior drawer test is performed by holding the patient’s calf in one hand and the heel tuberosity in the other and pulling the foot anteriorly to see if there is instability or dislocation of the talus.
Tears and ruptures of the heel-fibular ligament are rare. As the strongest ligament on the lateral side of the ankle, avulsion fractures of the distal fibular aponeurosis can often be seen on orthoanal radiographs in cases of heel-fibular ligament injury. These fractures should be differentiated from crest fractures in the case of peroneal tendon dislocation. The crest fracture is usually seen posterior to the fibula on a lateral x-ray. If it is difficult to differentiate, CT can be performed after the acute phase has passed. old distal fractures of the fibular apophysis may be seen on X-ray or congenital seed bones, at which point the patient’s history should be followed and can be identified by the rounded edges of the small bone mass. If the heel fibular ligament has caused an avulsion fracture, there is a possibility of surgical treatment.
It is important to identify whether the patient has an acute peroneal tendon dislocation. In patients with a dislocation, the pain is located posterior to the ankle joint and can be exacerbated when the peroneus longus is dorsiflexed and abducted from the foot against external forces.
In patients with talar deltoid, the sprain may cause a fracture of the deltoid, triggering long-term posterior ankle discomfort. In patients with heel-spur joint, the sprain may cause a fracture of the heel-spur joint and prolonged unrelieved pain.
Treatment
Emergency treatment
The main problem after an acute injury is swelling and pain in the ankle joint. The recognized “RICE” principles of Rest, Immobilization, Cast, and Elevate are used to treat sprains in the emergency setting. There are many established medical device manufacturers that make professional ankle fixation braces that can replace traditional casts. They are easy to wear, light weight and aesthetically pleasing, but the cost is high and there are few products suitable for public consumption in China. If a cast is not available after a sprain, or if the patient does not accept a cast fixation. In the premise that the patient only for the anterior talofibular ligament injury, you can full adhesive elastic bandage 8 fixed. Care should be taken not to apply deliberate pressure during fixation, otherwise it will tend to be too tight as the swelling increases.
Patients with lower tibiofibular joint injury need to be fixed in a cast or with a special brace.
For 24 hours after injury, ice is the main application; after 24 hours, physiotherapy and heat can be added. Pain is usually relieved with oral nonsteroidal anti-inflammatory drugs, such as ibuprofen. Other blood-activating drugs such as Yunnan Baiyao can also be taken. Non-weight-bearing activities can be started after the injury, but only when the brace is immobilized. Immobilization of the ankle joint can reduce pain on one hand and prevent cartilage damage or re-traumatization due to ankle instability on the other.
Usually the ankle is immobilized until the ankle swelling subsides and the pain disappears, usually 1 week to 6 weeks.
Surgical treatment
For Grade I and II injuries, non-surgical treatment can provide satisfactory results.
For Grade III injuries, some physicians believe that early surgical repair can lead to mechanical stability of the joint and thus achieve good clinical results, while others believe that non-surgical repair can lead to satisfactory results in most patients, even if a small number of patients become chronically unstable later on.
For patients with severe grade III injuries after repeated sprains, large avulsion fractures of the outer ankle, combined with more severe medial ankle injuries or osteochondral injuries of the talus, surgery is required in one stage.
Chronic instability
Patients with recurrent ankle sprains are associated with post-injury proprioceptive impairment, when there is functional instability of the ankle joint. Treatment consists mainly of rehabilitation exercises such as peroneal muscle strength training, Achilles tendon pulling, ankle balance board and balance disc exercises. The duration of training should be no less than 10 weeks. In addition, the use of bandages and braces for external fixation can reduce ankle hypermobility and increase ankle stability, and Freman reported that after functional rehabilitation, 70-85% of functional instability can be achieved with good results.
For patients with mechanical instability, functional rehabilitation should also be performed first, and if conservative treatment is not effective, surgery can be considered.
Patients with ankle sprains that may be complicated by cartilage damage to the talus, long-term repeated sprains, or chronic osteoarthritis that develops after the sprain, need further related surgical treatment.