What is injured when I sprain my ankle?
An ankle sprain is an injury to the soft tissue structures around the ankle that help provide the joint with stability. Although structures such as the joint capsule or muscle tendons that cross the ankle can be injured at the same time, most often when we refer to an “ankle sprain,” we are really talking about injury to one or more of the ligaments surrounding the joint. Ligaments are bone-to-bone attachments that prevent excessive opening of the joint in any given direction. There are three major groups of ligaments around the ankle.
The deltoid ligament is on the medial side (towards the midline) and is a broad, fan- shaped ligament that originates from the medial portion of the tibia and attaches to the heel bones from front to back. The deltoid prevents excessive eversion (turning of the ankle so that the bottom of the foot is facing laterally [to the outside]). It is injured when the foot is forcefully everted, although deltoid injuries account for only about 10% of all ankle sprain injuries.
Another set of ligaments connect the tibia and fibula together, helping to stabilize the roof of the ankle joint. Injury to these ligaments is
commonly referred to as a “high” ankle sprain, and patients with this injury do not tolerate pushing-off with the ankle with running or jumping, or absorbing landings, since these stresses tend to force the tibia and fibula away from each other. These ligaments can sometimes be injured in combination with others in the ankle.
By far the most common type of ankle sprain injury occurs at the lateral (outer) ankle. Here there are three ligaments that individually connect from the fibula bone to the heel bones at the front, mid-portion and back of the ankle joint. These ligaments prevent excessive inversion (turning of the bottom of the foot in towards the midline) and rotation of the foot at the ankle. Injury can occur to any or all of these, depending on how the injury actually occurred. Lateral ankle sprains are more common because when the ankle is pointed in a toes-down position (we refer to this as “plantar flexion”) there is more motion within the ankle joint, and less stability. The natural tendency when the foot is in plantar flexion is to also invert the ankle, whereas the anatomy of the ankle tends to keep us out of excessive eversion. When a lateral ankle injury occurs, whether and how much associated rotation there is will determine the type and degree of overall injury.
When the ankle is sprained, there can also be associated bony injury. The joint surface inside the ankle is subject to damage when the bones that line the joint collide with each other. This can range from superficial damage to the overlying articular cartilage to microfractures that can ultimately detach and become loose bodies within the joint. Other bones that can fracture during an ankle sprain are the fibula, talus and the long bones of the foot itself. Tendon tears can also occur, and are sometimes difficult to detect initially.
For the first few days after an ankle sprain, the ankle should be kept elevated with a compressive wrap applied in order to allow more rapid control of swelling. Ice should be applied at 20 minute intervals, 3-4 times per day. If your ability to bear weight is impaired, medical evaluation is probably warranted. Your doctor will determine if x-rays are necessary, and if there is any evidence of other more subtle injury. Crutch use should for the most part be minimized, and unless there are findings on your x-rays that would warrant longer use of them, they should be discontinued as soon as possible. Range-of-motion and balance training exercises should be started immediately. Anti-inflammatory medication may be prescribed to help reduce swelling, at the discretion of your doctor.
Why do people tend to continue to re-sprain their ankle after an initial sprain?
The ligaments that stabilize the ankle carry nerve receptors within them that give the brain feedback when they are stretched tight. Ordinarily, the brain processes this information subconsciously (and very quickly) and adjusts your body position to prevent injury. Once the ligaments are torn, these feedback loops stop functioning effectively, and patients become reliant on “conscious” feedback pathways (such as vision) that take more time. The difference in time between the subconscious and conscious pathways can be enough to allow the ankle to re-sprain before the body can adjust properly. This natural balance sense that exists prior to injury is termed “proprioception.”
Can I regain this balance control?
Yes! Everyone who sustains an ankle sprain should be started with home exercises with the goal of proprioceptive retraining. For an initial sprain (where rehabilitation potential is highest) or once a pattern of repeated injury has been demonstrated, your doctor may elect to start you in organized physical therapy to assist with this balance retraining, as well as maximize strength of the muscles that cross the ankle joint. Once stability and strength are improving, sport-specific exercises can be introduced.
Are there any warning signs I should look for?
Most ankle sprain injuries follow a fairly predictable course, with a near-total resolution in symptoms (with the exception of residual balance problems as described above) within 4-6 weeks of the injury. As a rule, we tell our patients to re-contact us for any of the following reasons:
• An inability to get off crutches by one week from the time of the injury.
• Swelling at the ankle continues to be a problem by the third week.
• Progression into sports participation is still impaired by the seventh week (excluding the most severe sprains or “high” ankle sprains.)
Any of these findings could indicate subtle joint injury not detectable on plain x- rays, and at the discretion of your doctor, consideration may be given to further imaging with an MRI to more fully evaluate the joint.
Should I wear an ankle brace?
Ankle braces are often helpful to protect the joint from injury while the muscles around the ankle are still weak. These braces should be worn more frequently early on, and their use can be restricted to periods of exercise or other high levels of activity as time from the injury passes and your symptoms are improving. Ankle tape prior to practice is an acceptable alternative if someone knowledgeable in taping is available. Generally though, athletic tape starts to relax about 30 to45 minutes after application, so in most cases, unless it is reapplied halfway through a practice or game, it is probably providing insufficient protection by the end of the session.
Are there any other precautions I should take?
It’s probably best to exercise in a shoe with a wider base for a few months after the sprain injury occurs, since narrow shoes provide less protection from side-to-side motion and can increase your chances to re-injure the joint.
Maximizing your strength through the hips and thighs will also improve your body’s ability to control your legs and keep you out of situations where sprains can occur. This problem can be identified, and specific exercises coordinated through your primary physician’s office or through the office of a local sports medicine physician.