How frequently do ankle sprains occur?   

Ankle sprains are the single most common sports medicine injury.  

What kinds of ankle injuries are there?  

Ankle injuries can be classified in different ways.  For some examples: 

What is structures are involved with ankle injuries?      

First the bones:  The ankle is comprised of three bones: the two leg bones--the tibia (shin bone) and fibula--(which most people inaccurately call the ankle bones) and the true ankle bone called the talus, which is the bone that lies between the tibia and fibula.  

Then the soft tissues:  Surrounding all the joints is a thick envelope of tissue called joint capsule.  If you've ever seen the white, connective tissue that surrounds a the joint of a chicken or turkey leg--that's primarily the joint capsule.  It's quite strong, and it envelops all sides of these bones, just like you could place tape around two pencils placed eraser to eraser to hold them together.  Inside and outside the joint capsule are the ligaments--short, tough soft-tissue bands that reinforce and provide additional stability to the joint capsule. 

The articular cartilage is a glistening, white, smooth tissue that covers the two opposing bone surfaces that make up the joint.  This cartilage produces the joint fluid, known as synovial fluid, which lubricates the motion of the joint. 

Additionally, there are several tendons (connective tissue attaching muscle to bone) passing over and past the ankle joint. 

What motion causes most ankle injuries? 

The dominant normal motion of the ankle is an up (dorsiflexion) and down (plantarflexion), gliding motion.  Most ankle injuries are caused from a force applied to the ankle which is contrary to this normal anatomical motion.     

While you can suffer injuries where the ankle is bent too far in the dominant up-and-down motion, these injuries are relatively rare.

More common is an injury to the ankle from a rotational force--where the body, knee and leg turn left or right as the foot stays in place on the floor.  

But most ankle injuries occur when the ankle bone is bent too far to one side or the other.  This motion is called inversion or eversion, depending on the direction of movement. 

Most of this inversion and eversion motion is supposed to be performed by the joint beneath the ankle bone (the subtalar joint) or in the forefoot (the midtarsal joint).  So when those stresses are transferred onto the ankle joint instead, damage often occurs.   

Because of the way the ankle joint is constructed, most ankle injuries (90%) occur in the direction of inversion.

What tissues get injured in an ankle injury?

Any of the bones or soft tissues may be damaged in an ankle injury.  But most injuries begin as a simple strain to a ligament (usually the anterior talofibular ligament) on the outside portion of your ankle.  If the mechanism of injury progresses, the injury may progress to involve more ligaments (the posterior talofibular and the calcaneofibular ligaments) and the joint capsule.  As the mechanism of injury progresses, the injury may involve bone, in addition to the soft tissues.     

The disruption of any of these structures may lead to dysfunction of the ankle joint, and recurring sprains may result, so a proper examination, appropriate diagnostic testing (X-ray, MRI, CT scans), accurate assessment and appropriate treatment by a qualified foot and ankle specialist is necessary to achieve the best return to normal function possible.    

How are ankle sprains treated?   

Following an ankle injury, the patient should, when possible, seek immediate emergency care from a qualified foot and ankle specialist, as improper treatment of ankle injuries can delay recovery for weeks, and reduce the threat of permanent damage and recurrence of the injury.    

Circulation, nerve function and joint motion and stability will be assessed.  X-rays should be taken to rule out any broken bones, and if any fractures are present, immediate surgery may be indicated.  

Assuming no fractures are present, and the injury involves soft tissues only, the extent of the soft-tissue injury is assessed and graded.  

How is the degree of soft-tissue injury graded?  

Most podiatrists grade ankle injuries on a 3-point scale:  

Patients who exhibit localized tenderness but no instability are classified as having a Grade 1 injury.  The ankle still maintains the normal range of motion with little in the way of diminished function.  More than half of all ankle sprains are classified as Grade 1 injuries.   

A Grade 2 injury is characterized by moderate to severe pain, swelling, bruising and abnormal range of motion.  Grade 2 injuries usually involve damage to the ligaments.  

A Grade 3 injury involves a complete ligament tear.  There is severe edema, bruising and disabling pain.  There is joint instability and a severe loss of function.  Walking is usually impossible.   

 How are ankle sprains treated?  

Despite the frequency in which ankle injuries occur, the complexity and severity of ankle injuries is under-appreciated, and ankle injuries are under-diagnosed and under-treated.  

Often, we have seen patients given just a simple Tensor wrap (Ace bandage) or Air Cast, and the patient is sent home walking--even when bones may be broken.  In reality, ankle injuries should be taken more seriously.  

The initial treatment for Grade 1 or 2 injuries should involve non-weight-bearing immobilization with a soft or hard cast, along with rest, ice, compression, elevation, and anti-inflammatory medications. This will diminish the initial inflammatory response.   When possible, range of motion exercises (which promotes orderly ligamentous healing), physiotherapy and muscle-strengthening exercises are begun and the patient may gradually return to normal activities.  With proper treatment, these injuries heal within a matter of a few days or weeks.  

For Grade 3 sprains, casting or surgical repair are considered depending upon the severity of the injury.   

How can you prevent ankle sprains?  

It has been shown that athletic taping and removable ankle braces are effective in resisting inversion injuries.  High-top runners (athletic shoes) have also demonstrated effectiveness in preventing these injuries.