Often we have patients who present to the office with a feeling of “giving out” of their ankle that is not typically preceded by a triggering event at the moment they suffer that feeling. They often have associated ankle pain and relay a long history of athletic related ankle sprains or ankle fracture in the past. That one phrase, of feeling as if the ankle will “give out” combined with the patient’s history is often diagnostic of a common condition called Chronic Ankle Instability.
Instability at the ankle typically stems from the outside or lateral part of the ankle joint, where the most commonly injured ligaments in ankle sprains reside. The internal twisting of the leg and foot with an ankle sprain often times stretches, tears or ruptures these ligaments, and it is often very difficult for those ligaments to heal. In addition, healing takes place in a non-uniform fashion with improper rehabilitation, as most ankle sprains typically go unevaluated and untreated by the patients Podiatrist.
There are three main ligaments that make up the lateral ankle ligaments and often two of those are easily damaged in ankle injuries eventually leading to chronic instability secondary to laxity within these ligaments. The cycle is continues. Once those lateral ligaments are damaged, they tend to lengthen and have less inherent stability than prior to the first ankle sprain injury. This makes them prone to additional injury that occurs over and over again. In addition to a history of initial sprain, patients with a high-arched (cavus) foot type are prone to ankle injuries and eventual ankle instability because of the nature of their foot shape. The way the foot sits in this foot type lends itself to an increased risk of injury and eventual ankle instability.
Several diagnostic examinations can be performed to help the Podiatrist hone in on ankle instability as the underlying cause of a patient’s condition.
The first is simple palpation of the ankle joint. In any of these instances it is important to rule out any type of fracture to either the ankle or foot bones, so palpation of crucial areas is important. However, pain over the direct area where these lateral ankle ligaments reside is diagnostic of injury, especially when there is no pain on palpation to the bones that make up the ankle joint.
The remaining two examinations can be done with the aid of x-ray, where by the ankle joint is passively moved by the x-ray technician to specifically evaluate the strength of the tendon when compared to the opposite, unaffected ankle. The technician will try to pull the heel forward while stabilizing the leg in an examination called the Anterior Drawer Test, effectively evaluating the integrity of one of the lateral ankle ligaments. The next examination, referred to as Talar Tilt, evaluating the integrity of a different lateral ankle ligament. Positive results in performing either or both of these examinations indicates damage to the involved ligaments and thus is diagnostic of instability when associated with symptoms.
The key with chronic instability is to catch the instability before it becomes a chronic reoccurring problem. Early ankle support with bracing in addition to physical therapy will help decrease the healing time and increase the feedback from these ligaments as well as the ankle joint, helping to increase stability on the affected leg and reduce the occurrences of “giving out” episodes.