The ankle is a joint that connects the lower leg to the foot. The tibia and fibula are the two bones from the lower leg that together with a bone from the foot (talus) form this joint (referred to as the ankle mortis). Ligaments add the stability needed for proper alignment and functioning. As with most joints, the ankle is designed to balance flexibility with stability. Based on the location, the ankle joint needs to be able to tolerate the full body weight during walking, running, and jumping.
A dislocation occurs when the bones no longer hold their normal anatomical relationship. A dislocation interrupts the relationship between the talus and tibia in the ankle. Medical professionals describe the dislocation from the perspective of the talus to the tibia.
The most common ankle dislocation is a posterior dislocation (the talus moves posterior in relationship to the tibia). This occurs when a force drives the foot backward. As with all ankle dislocations, the likelihood of an associated fracture is very high.
Besides a posterior dislocation, an ankle dislocation can also occur anterior, lateral, and superior.
A significant amount of force causes all ankle dislocations, making it likely that there are also other injuries present. Fractures of the tibia and fibula are very common, as well as ligamentous disruptions.
With all ankle dislocations, the concern exists for related neurovascular injuries (injuries of the nerves and the blood supply). To avoid long-term complications, these need to be diagnosed and treated quickly (usually with reduction of the dislocation, sometimes even before X-rays are taken).
A force moving the foot backward in relationship to the tibia and fibula causes a posterior dislocation (the most common ankle dislocation). Usually, the ankle is flexed backward (plantar flexed) as the trauma happens. As with all ankle dislocations, a significant force is needed to dislocate the foot. Motor vehicle accidents, falls, and sports injuries are the most common causes.
Anterior dislocations occur when something forces the foot to move anteriorly.
Lateral dislocations are due to inversion, eversion, or external and internal rotation of the ankle. This twisting motion usually results in a fracture in addition to the dislocation.
Superior dislocation is usually due to a fall from heights that pushes the talus upward. Frequently, there are related injuries especially to the patient's spine.
Children and adolescents have the most ankle dislocations, and they occur more frequently in males, which is probably related to the higher incident of traumatic injuries found in males.
Injuries related to motor vehicle accidents, falls, and sports injuries are the common causes of ankle dislocations.
Patients who have medical conditions causing joint hyperlaxity or hypermobility (such as Ehlers-Danlos syndrome) are at increased the risk for dislocations. A history of multiple ankle sprains (causing laxity of the ligaments) and weakness of the muscles around the ankle increase the chances of a dislocation.
Due to the significant trauma causing these injuries, there is associated significant pain and swelling.
People may note bruising. An inability to walk is common.
The ankle appears deformed and is painful to palpation.
If the dislocation damaged nerves, numbness or tingling can be present.
Because the dislocation can disrupt the blood flow to the foot, the foot can appear pale and show delayed capillary filling. These are indications for prompt reduction of the injury.
Your physician will ask about your history of injuries, which will point to the mechanism and possible type of dislocation. Questions about your past medical history, allergies, and medications will usually also be part of the history.
The deformed appearance of the ankle often points to the diagnosis. In addition, a physical examination to establish if all the nerves are intact and if the blood supply is compromised usually follows. The patient will not be able to bear weight and often be in significant pain.
Depending on the injury mechanism, the health care provider will also examine other parts of your body besides just the lower extremity.
A medical professional will take a plain X-ray to establish the diagnosis and evaluate you for fractures related to the dislocation. Health care professionals usually repeat the X-ray once the dislocation has been reduced.
Depending on the extend of your injuries, a doctor might order additional radiologic tests to help evaluate you for other injuries (CT or MRI; looking for more detailed joint images or fractures not apparent on the plain X-rays and to evaluate the tendons and ligaments more closely).
An ankle dislocation will usually require immediate attention in an emergency department.
Emergency medicine physicians will diagnose the injury and start the treatment. Orthopedic surgeons are involved in the care especially if surgery is required. If medical professionals suspect multiple other injuries, a general surgeon or trauma surgeon can be involved in the patients care.
The acute treatment will require moving the ankle back into its natural position (reduction of the dislocation). Depending on the dislocation, this might require slight traction and IV medications (for pain, sedation, and to relax the surrounding muscles). A medical professional will flex your knee and apply traction to your foot. Usually, health care professionals perform the reduction after they take and review the X-rays, but in cases where the blood supply is compromised, reduction might need to occur immediately.
After the reduction, medical professionals repeat the X-ray and usually apply a cast or splint.
In rare cases, health care professionals cannot accomplish a reduction and will require the patient to go to the operating room for reduction and injury repair.
Patients with these injuries will follow up with an orthopedic surgeon for further evaluation and care.
Once the injury has healed, physical therapy can assist in establishing the best possible long-term outcome.
Depending on the extent of related fractures and the need for surgery, time to heal and recovery can vary widely from four weeks to several months.
Due to the severe trauma causing ankle dislocations and the associated fractures, the patient often does not have 100% recovery to pre-injury form.
If there was prolonged disturbance of the blood supply or nerve damage, the patient can remain with significant disabilities and restrictions.
Loss of range of motion, chronic pain, or instability are all possible complications of ankle dislocations.
A bruise is a common skin discoloration that results from the breakage of tiny blood vessels leaking under the skin after a traumatic injury. Blood from damaged blood vessels beneath the skin collects near the surface to appear as what we recognize as a black and blue mark. This mark is from skin discoloration by red blood cells and their contents. A bruise is also known as a contusion.
