What is Ankle Dislocation?
Ankle dislocations are quite common and people often come across them in emergency departments. There are mainly two types:
1. A genuine dislocation that doesn’t involve any fractures.
2. A dislocation that’s combined with a fracture; this happens most of the time.
The ankle joint consists of three major connections, namely the talocalcaneal (subtalar), transverse-tarsal (talocalcaneonavicular), and the tibiotalar (talocrural) joints. The real ankle joint is the tibiotalar joint (connecting the tibia, fibula, and the talus bones). This joint is ring-shaped and allows the foot to bend down (plantarflex) and bend up (dorsiflex) at specific angles. Below the ankle, there’s a joint connecting the talus and calcaneus bones, which enables the foot to turn in (invert) and turn out (evert) significantly. There’s also a joint between the talus and navicular bones, which allows for the same movements. The combination of these joints gives the foot a marvelous ability to adjust to different pressures while walking and doing other activities.
Despite handling exceptionally heavy loads and supporting many times the human body’s weight, the ankle can maintain a considerable range of motion. However, if the ankle is under too much stress due to pushing off in different directions, it can possibly dislocate.
The ankle’s stability mainly depends on three sets of ligaments, which limit the motions between the bones and support the ankle against excessive turning. Normally, these ligaments are incredibly strong, meaning that it’s more likely for the bones to break, causing a dislocation with a fracture.
What Causes Ankle Dislocation?
Ankle dislocation means that the joint of the ankle has been moved away from its usual position. This can happen in a few different ways, depending on things like if there’s a fracture or not. A dislocation with no fracture has been reported to happen in various ways and directions. The most common way it happens is if the ankle is bent down as far as it can go, with an axial load and the foot twisted inwards. This allows for the talus bone (a small bone in the ankle) to move forwards out of the joint, leading to damage and the tearing of certain crucial ligaments. This results in a dislocation to the back and inside part of the ankle, which is the most common type of pure ankle dislocation.
Research using cadavers recreated this injury by bending the foot down as far as possible while applying stress causing the foot to invert or evert. This led to an ankle dislocation either towards the inside or outside, without a fracture, but with damage to the ligaments. Superior dislocation, or upward dislocation, often happens when a twisted-out foot is pulled up strongly. This causes the rupture of a key ligament, leading to an upward dislocation of the ankle joint. Factors that can predispose someone to dislocation include weak peroneal muscles, previous strains, lax ligaments, and the shortness of a part of the ankle called the medial malleolus.
Fracture-dislocations of the ankle, which are more common, happen in a similar way to non-dislocated fractures. The most common resulting fractures, called bimalleolar and trimalleolar, are often the result of a force pushing away from the body and the dislocation of the talus bone. This is how the ankle looks to be dislocated when it is examined. Sometimes these dislocations will rejoin by themselves, leaving a fracture. These fractures are often classified according to a system called the Lauge-Hansen classification system, which categorizes them based on the position of the foot and the direction of the force. However, the reliability of this system is often questioned.
Risk Factors and Frequency for Ankle Dislocation
Pure ankle dislocation, meaning a dislocation that occurs without any accompanying fracture, is extremely rare. It only happens in about 0.065% of all reported ankle injuries. This figure takes into consideration not just bone injuries, but also softer tissue damage. If we look at all reported ankle dislocations, only 0.5% are pure dislocations – fractures make up the rest. Despite this, the actual number of pure dislocations might be somewhat underestimated. Sometimes, an ankle may be fixed into place without any need for a hospital, which could mean some incidents go unreported. Some ankle fractures also include tibiotalar dislocations, which happens in roughly 21-36% of cases.
This type of injury is most commonly seen in males, making up 72% of cases. The most frequent causes of ankle dislocations are sports-related accidents and car crashes, each responsible for about 30%. The ankle usually dislocates in a posteromedial direction, which happens in 46% of cases.
In some rare cases, it might be impossible to fix an ankle fracture-dislocation due to the position of soft tissue or fragments of the broken bone. An example of this is the “Bosworth Fracture”. This occurs when the top part of the fibula, a bone in the lower leg, gets stuck behind the tibia, another bone in the lower leg. This kind of injury often goes unnoticed in basic x-ray images and can’t be fixed in an emergency department without surgery.
Signs and Symptoms of Ankle Dislocation
If a person’s foot is dislocated from their shin bone (tibia), it can result in serious problems if not dealt with quickly. Pain relief and prompt realignment of the foot and ankle are crucial. Delays can cause skin damage and the formation of fracture blisters, which may lead to a permanent disability. Once other life-threatening injuries have been treated, the dislocated ankle should be put back in place. This usually requires a process involving sedation. Ankle dislocations are commonly seen and are known to require such a procedure. Firstly, recognizing the pain that the patient is experiencing is essential, and pain relief should be given before trying to align the ankle. These injuries often require surgery, particularly in cases involving open fractures. It’s important to call an orthopedic consultant for an open fracture, dislocation with blood flow or sensation issues, fractures involving two or three bones, a rupture of the connective tissue between the shin bones, or impact fractures of the lower shin bone.
During an examination, several things need to be checked. These include the direction the foot is pointing in relation to the ankle, whether the major pulses in the foot are present, how quickly blood returns to the foot’s extremities when pressed, any other injuries to the foot, and where tenderness and swelling are situated. Another key aspect to check is the sensation on the top, outside, and inside of the foot, and near the big and second toe, which is the area served by the deep peroneal nerve. The ability to flex and extend the toes should also be noted. These important exam results should be recorded before and after the foot is manipulated.
Testing for Ankle Dislocation
Before trying to realign the ankle and tibia-fibula bones, it’s important to get x-rays from different angles. Doctors typically need three x-ray views of the ankle: the front view, the side view, and a special lateral view called the Mortise. The Mortise view is captured by positioning the x-ray machine in the front while slightly rotating the ankle internally by 15 degrees. It’s also crucial to have a full-length x-ray of the tibia-fibula to check for specific injuries, such as a Maisonneuve-type injury. This injury is caused by energy transferring through the interosseous membrane, leading to a fracture or dislocation at the higher end of the fibula or fibula-tibia joint.
There are some situations where realignment might be necessary even before x-ray imaging is completed – for example, if the skin over the injury is tented or stretched, or if the injury compromises neurovascular functions. However, studies have shown that there’s a higher chance of needing further alignment adjustments if it’s done before the x-ray (44% before x-ray vs. 18% after x-ray).
If the injury is a pilon-type fracture, which involves the weight-bearing area of the tibia, a CT scan might be necessary. But it’s recommended to consult with an orthopedic surgeon before going for a CT scan. This is because if a temporary external fixator is needed to stabilize the fracture, the CT scan should be taken after this is installed for proper pre-surgery planning.
Treatment Options for Ankle Dislocation
Your ankle can dislocate in five different directions: forwards, backwards, to the side, inwards, or upwards. Usually, the first four types of dislocations can be easily set back into place in the emergency room while you’re sedated. An upwards dislocation often results in a specific kind of bone fracture and needs to be seen by a specialist.
The aim of treatment is to realign the bones in your lower leg and foot, checking from different angles to make sure everything’s where it should be. Once your ankle is back in place, it should look like it’s back to normal.
Resetting an ankle dislocation is often a two-person job, although there is a method that allows one person to do it. It’s important to carefully follow the steps and techniques outlined below to properly reset a dislocated ankle:
For a forward dislocation, the steps are as follows:
- Flex your knee slightly.
- Grasp your forefoot with one hand and your heel with the other.
- Pull your foot upwards while applying traction and moving the foot and ankle back into position.
To reset a backward dislocation:
- Flex your knee.
- Grasp your heel with one hand and the upper part of your foot with the other.
- Pull your foot down and forwards while providing a counter pull on your leg.
The same steps apply for sideways dislocations, although you may need to move the foot laterally instead. Make sure to check for sensation, pulse, movement, and the return of blood flow in your toes afterwards. If everything’s fine, your leg will be put in a splint and bandaged up.
Once you’ve been treated, you’ll need to keep an eye on the condition of your dislocated ankle. For most ankle dislocations, you won’t need surgery. But in cases where you continue to experience discomfort or instability after a few weeks, you may need to get an x-ray or MRI to assess if there has been any damage to the ligaments in your ankle.
For severe dislocations that resulted in fractures, it’s often best to treat these with surgical intervention. The surgical approach would depend on the type of fracture, but the primary goal is to realign the broken pieces and make sure they’re secure.
Post-surgery, expect to be on crutches and avoid putting weight on your foot for at least six weeks. Patients who have diabetes may need a longer recovery period depending on how quickly they heal.
What else can Ankle Dislocation be?
An ankle dislocation or fracture-dislocation is usually obvious during a physical exam, where the doctor checks the position of the foot in relation to the shin bone (tibial crest) and kneecap (patella). This is a crucial step in diagnosing the issue accurately.
An injury called a subtalar dislocation might happen at the same time as an ankle dislocation or fracture-dislocation. Despite how they look, these injuries may not always mean the ankle is dislocated. Standard x-rays can show that the ankle joint (tibiotalar joint) is actually in its normal position.
High-impact incidents can cause a more serious injury, where the ankle bone (talus) gets fully dislodged, leading to dislocation in both the tibiotalar and subtalar joints. This type of injury can also be detected through a simple X-ray and needs immediate attention from an orthopedic specialist.
What to expect with Ankle Dislocation
If we’re talking about simple ankle dislocations, the overall outlook is generally good. A comprehensive review of this type of injury showed that after the right treatment was applied, most patients no longer displayed symptoms. However, some people, mostly women, did report persistent stiffness or the development of arthritis after trauma. People who had a non-invasive dislocation tended to experience fewer symptoms compared to those with invasive dislocations.
No one wants to deal with a poor outcome, but certain factors can increase the likelihood of this happening. These include being older, having a vascular injury, facing a delay before the dislocation is addressed, and having an injury to the lower leg’s tibiofibular ligament. Moreover, some patients have reported late complications such as stiffness, joint instability, and capsular calcification.
For cases where the ankle is both dislocated and fractured, the outcome can vary. Compared to non-dislocated fractures, ankle fractures with dislocation generally have long-term outcomes that aren’t as favourable. Unfortunately, these types of injuries result in increased pain and a decrease in daily life activities. Recent research has shown a higher rate of the need for repeat surgery for ankle fracture-dislocations compared to the non-dislocated group. Additionally, evidence of arthritis developing after trauma has been reported in up to 63% of patients who suffered an ankle fracture-dislocation.
Few factors have been found to influence these results, including the type of fracture, gender of the patient, and the accuracy with which the original dislocation was addressed. Despite these challenges, it isn’t all bad news. Even in these complicated cases, in the largest and earliest study of its kind, between 82% of patients evaluated within 2 to 6 years after the injury were classified as having either an “excellent” or “good” outcome.
Possible Complications When Diagnosed with Ankle Dislocation
The outcome and potential complications from a dislocation or fracture-dislocation of the ankle can vary greatly depending on several factors. The most common complications are infection, improper bone healing, skin death, and arthritis that develops after the trauma. What influences these outcomes can be things like how the injury happened, the type of fracture, whether the fracture is open or closed, and other health conditions the patient has.
More severe fractures and open fractures are usually caused by high impact injuries. Open injuries, where the skin is broken, have a high rate of deep infection (8%) and skin death (14%) after immediate fixing of the bone or bones.
In one study, it was found that patients who smoke and those with fractures involving both the inner and outer ankle bones had higher instances of infection at the surgical site. It’s important to note, however, that not all of these injuries were fracture-dislocations. Complications like improper bone healing, problems with wound healing, and deep infection were found more often in diabetics with ankle fractures, whether they were treated with surgery or not. For diabetic patients, the rate of these complications could be as high as 42%, compared to similar non-diabetic patients.
Another study, which was the most substantial and earliest prospective study involving 306 patients with dislocated or fracture-dislocated ankles who had surgery, followed these patients for up to six years after surgery. This study reported an infection rate of 1.8% and a rate for developing post-traumatic arthritis of 14%. However, more recent studies have reported a rate of developing post-traumatic arthritis of up to 63%.
Preventing Ankle Dislocation
After the correct repositioning and securing of an injured ankle in the emergency room, it’s important that patients fully comprehend several key points. They should be given crutches or a walker, and must not put any weight on the hurt body part. It’s imperative they understand these limitations and can adhere to them. Failure to do so could lead to their fracture or dislocation shifting again. They should also know how to take care of their splint, particularly ensuring it doesn’t get wet as this could damage its supportive quality and potentially harm the skin. If the splint becomes wet, they need to return to get it replaced.
Patients should also be instructed on how to correctly manage their pain, with Tylenol and NSAIDs as the initial treatments, and using any prescribed narcotic only when absolutely necessary. Additionally, it’s crucial they are made aware of a condition known as compartment syndrome. Though this is rare following an ankle fracture or dislocation, it can bring severe complications. Indicators of this include escalating pain that overpowers pain relief, the toes turning white or blue (suggesting a lack of blood flow), intense pain when stretching the toes, loss of pulses and a reduction in sensation in the foot and toes. If these symptoms appear, the patient should return to the emergency room immediately.
If the patient needs surgery to fix the injury, they should still follow all of the mentioned advice and heed any recommendations regarding the use of anesthesia. In particular, keeping the splint dry is once again highlighted, as this not only stops it from breaking down but also helps the wound to heal.
