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Ankle sprains affect millions of Americans annually. Although one of the most common forms of personal injury, ankle sprains are often misunderstood and improperly treated. The purpose of this article is to explain the most common types of ankle sprains and how to effectively treat them.
Understanding ankle sprains
The human ankle is a very complex joint. An ankle joint is about the size of a walnut. It consists of three bones and several different ligaments that change and work in an amazingly complex manner.
Any small disruption of the normal function of the ankle joint, such as a sprain, causes a change of the fragile function of the ankle joint.
As a surgeon, I've gained a very deep respect for the complexity of the human joints, especially the ankle joint. The ankle has an incredible design and load capacity. And consider the longevity! There's simply no man-made machine that compares to the uniqueness of the human ankle joint.
Now, let's take this special joint and turn it or twist it. And then, to make matters worse, let's bear our full body weight on it while the injury is occurring. I think you can easily see how an ankle injury can quickly become big trouble.
By a wide margin, the most common form of ankle sprain is the lateral ankle sprain, which affects the outside of the ankle.
At the lateral side of the ankle, the smaller ankle bone (the fibula), is attached to the talus (bone of the foot) by three small ligaments called the lateral collateral ligaments of the ankle.
The anterior (or front) ligament is the one that is injured in most ankle sprains. It's referred to as the anterior talo-fibular ligament (ATF). This is a relatively small ligament that runs from the anterior aspect of the fibular forward and attaches to the talus.
The next most often injured ankle ligament is just behind the ATF. This ligament is called the calcaneal fibular ligament. It extends from the fibula to the heel bone (calcaneus), and is considered sort of a "back-up ligament" to the ATF in common lateral ankle sprains.
Finally, we have the posterior talo-fibular ligament which runs from the fibula back to the talus. Only very rarely is it ever injured in a lateral ankle sprain.
There are several specific contributing factors to all ankle injuries. Many doctors view them as accidents, but I think you'll find that most podiatrists prefer to look a little deeper into the causes of ankle sprains. Quite a bit has to do with the biomechanics of the human foot. Let's take a closer look at some of these causes.
The first issue that we need to consider is a person's center of gravity. Where does his center of gravity line up over his foot? Does he have a tendency to roll to the outside of his shoe when he walks? Does he usually wear out shoes on the outside?
If so, there's a strong likelihood that his body weight, or center of gravity, is more centered over the outside of his foot instead of directly over it.
There are technical terms that describe this combination of foot mechanics, including forefoot valgus and rearfoot varus, but suffice it to say that these folks are more likely to sprain their ankles than others.
Any time a person with these special foot characteristics is placed into a situation where they're likely to sprain the ankle, they will. Basketball is perhaps the best example. A player leaps up to catch a pass and his feet leave the ground. As he lands, he does so partially on another player's foot.
The normal ankle joint will be able to maintain it's integrity and not sprain, but the patient described above with the bad ankle will be much more prone to injuring his ankle in this type of situation.
I'm sure you remember people saying they have "weak ankles". Their ankles aren't actually weak, they're simply prone to sprains because of their center of gravity and the biomechanical properties of the foot.
Physicians grade ankle sprains according to the location of the injury and the degree of damage that the ligament has sustained.
We typically speak about grade I, II, or III ankle sprains. And most often they'll affect the ATF ligament. These sprains hurt considerably when they first happen, then calm down for an hour or so. Then as they start to swell, they begin to hurt and become discolored, depending upon the severity of the injury.
In a grade I ankle sprain, the swelling is usually localized to the site of the ATF ligament on the anterior ankle. The more severe the sprain, the more diffuse the occurrence of swelling and bruising.
Although the lateral ankle sprain is the most common by far, there are other ankle sprains that should be mentioned. The next most common ankle sprain is a sprain to a joint next to the ankle.
The subtalar joint is the joint located between the talus and the calcaneus (heel bone). This is the joint that controls the ankle's side to side motion, such as walking on uneven surfaces or on hillsides.
For the sake of conversation, most physicians refer to the subtalar joint as being part of the ankle. The subtalar joint is held together by the cervical ligament, which is also susceptible to sprain.
Treating sprained ankles
Let's assume for a moment that we're treating a common lateral ankle sprain. You can think about treating it in two phases. The first phase is the management of the acute phase such as pain, swelling, and the inability to walk on the ankle.
The second phase may be even more important however. The second phase is for the prevention of recurrent sprains.
Phase I -
In the first phase, remember the acronym RICE:
R- rest
I- ice
C- compression
E- elevation
Rest is imperative following an ankle sprain. You need to give the ankle several days rest before getting back to any activity. Bear weight on the ankle only with tolerance. Some weight bearing is beneficial from the standpoint of breaking up scar tissue and re-gaining an early range of motion, but too much weight bearing leads to unnecessary swelling.
Another form of rest is ensured by casting. In cases of severe sprains, I'll instruct the patients to wear a removable walking cast. The cast limits the motion of the ankle, yet can be removed for showers and at night.
Ice is a must for controlling swelling of the sprained ankle. Personally, I don't recommend heat at any time during the healing of an ankle sprain. But the more ice, the better. Care must be taken not to damage the skin, especially if a patient has a loss of sensation such as diabetic neuropathy.
Compression is also a must to help control the swelling. This can be accomplished with many different devices, including ace wraps or ankle supports.
And finally, you need elevation. Elevation is yet another effective method of controlling swelling. Ankle sprain patients usually recognize the benefits of elevation even weeks after the injury takes place.
Phase II -
There's a lot that we can do to prevent a second sprain (or a recurring series of sprains). The choice of treatment will depend upon the patient and his usual activities. Issues such as work duties, athletic involvement, and social activities must all be considered.
Let's look at a few examples. Perhaps a patient participates in a unidirectional sport such as running. An ankle brace would be cumbersome and would likely detract from the enjoyment of a run.
For this patient, we would prescribe an arch support referred to as an orthotic. The orthotic would be modified to control the lateral rotation of the patient's foot and help to center his body weight back directly over the foot. An orthotic can be an excellent tool for the chronic ankle sprainer who is a runner, or even for use in street shoes.
But how can we protect those involved in bi-directional sports, such as tennis or racquetball? An ankle brace should be used for these sports. The side to side forces are simply too great to be effectively controlled by the use of an orthotic.
There are many varieties of splints and braces on the market today. I'm not a very big fan of stirrup braces for use with chronic sprains. They're helpful in the acute phase of ankle sprains to help control edema, but they really don't help all that much in controlling the biomechanics that often cause lateral ankle sprains.
I do recommend lace up braces, especially those that will lace into the shoe. Lace up braces actually ensure that the brace and shoe work together to support and protect the ankle.
Some forms of physical therapy are helpful as well. Most of the common exercises to help strengthen and reorient the ankle can easily be performed at home.
Physical therapists will use proprioception exercises to re-educate the ankle ligaments. Proprioception is simply the sense of being aware of where you are in space. The lateral collateral ligaments benefit greatly from this re-education process. The concept is to attempt to make the ligaments more responsive to the next possible injury.
Proprioception exercises:
When you can, stand in a doorway and place all your body weight on the injured ankle. Balance yourself by holding on to the door. As you begin to gain more balance, close your eyes.
This isolates your ankle and forces it to be re-educated. You'll be amazed at what spending only five minutes a day will do for gaining more ankle stability over the course of ten days or so.
Some patients are prone to getting chronic ankle sprains even after their first sprain. If a patient keeps having severe, recurrent sprains, surgical stabilization of the ankle may be required.
Ankle stabilization is a useful surgical procedure that involves the repair of the lateral collateral ligaments. And occasionally, in severe cases, a tendon transfer may be needed to help stabilize the lateral ankle. These procedures are often quite extensive, and they all require prolonged periods of immobilization.
A new arthroscopic method referred to as arthroscopic monopolar radiofrequency thermal stabilization is now being developed. AMRTS uses a radiofrequency probe to shrink the lateral wall, or capsule, of the ankle joint. The lateral collateral ligaments are treated with AMRTS as well.
This new technique is currently under investigation, but it holds much promise as a minimally invasive alternative to the traditional methods of correction.
Dr. Jeffrey Oster serves as medical director of myfootshop.com.
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