Anterior ankle impingement is a relatively common problem characterized by pain at the front of the ankle. Symptoms are often aggravated when forcing the foot upwards (dorsiflexion). Often the impingement occurs as a result of a bone spur (osteophyte) at the front of the ankle joint, although impingement can also occur secondary to soft tissue. Ankle impingement is commonly associated with ankle arthritis, but it can also occur in soccer players, dancers, and other individuals who repetitively load the ankle joint. Treatment can be non-operative (i.e.wearing shoes with a slight heel, limiting activities, taking anti-inflammatory medication, taping the ankle, etc.) or operative (i.e. removing the bone spur and/or soft tissue). As the bone spur has usually formed in response to some other stimulus (ex ankle arthritis), it is not uncommon for the bone spur to recur after it has been removed surgically.
The main symptom of anterior ankle impingement is pain at the front of the ankle joint (Figure 1). Symptoms occur when the foot is forced upwards (dorsiflexion) causing the two bones at the front of the ankle (tibia and talus) to jam (impinge) into each other (Figure 2). If the impingement is from a bone spur (osteophytes), as it often is, then a noticeable loss of upward motion of the ankle joint may be present. Anything that causes the ankle joint to jam together (i.e. Sporting activities, or sudden forced upward movement of the ankle joint) is likely to precipitate an increase in the discomfort.
The main cause of ankle impingement is ankle arthritis. The increased blood flow and inflammation that occurs with ankle arthritis often leads to increasing bone spurs (osteophytes) at the front of the ankle joint. This is why patients may also have pain throughout their ankle although often pain at the front of the ankle is the main complaint. It is not uncommon for patients to have a history of ankle trauma or some other cause of ankle arthritis.
Ankle impingement can also occur in individuals who repetitively irritate the front of their ankle joint, such as soccer players. In some individuals, the ankle stress associated with kicking a soccer ball may lead to the development of bone spurs in the front of the ankle.
Some anterior ankle impingement is the result of excessive soft-tissue in the front of the ankle, leading to impingement. This is often from an excessive amount of joint capsule leading to impingement and limited motion. Unlike impingement from bone spurs, this type of impingement will not be seen on an x-ray, although it may be seen on an MRI.
The classic physical exam findings are tenderness along the front of the ankle joint that is worsened when moving the foot upward (dorsiflexion), and limited upward movement of the foot (limited dorsiflexion).
Most anterior ankle impingement is the result of bone spurs at the front of the ankle and this can be seen on an ankle x-ray taken from the side (lateral view). The size of the bone spur can vary from very small to quite large (Figure 3). X-rays may also demonstrate mild, moderate, or even severe ankle arthritis, which is characterized by loss of the joint space (equivalent to loss of the joint cartilage). A fluoroscopy (moving x-ray) can demonstrate the actual impingement as it happens.
In most instances, symptoms can be improved considerably with non-operative treatment. Non-operative treatment is designed to either: limit the number of times (and force) that the ankle joint jams; or decrease the pain response from the ankle joint. Some potentially effective non-operative treatments are:
In some instances of anterior ankle impingement, operative treatment may be helpful. If the main cause of a patient’s symptoms is from impingement (rather than ankle arthritis), removing the prominent impinging bone spurs and/or soft tissue can help symptoms. Surgical treatment of ankle impingement involves removing the prominent bone spurs and/or soft tissue either arthroscopically or by opening up the ankle joint with an incision. If the bone spurs are large, it is often more efficient and effective to make a larger incision and open up the ankle joint to remove the bone spurs rather than attempt to do this arthroscopically. Removal of all bone spurs is not required, rather only those which are noted to be causing impingement at the time of surgical inspection.
Surgery to remove impinging bone spurs from the front of the ankle will not typically help symptoms if the pain is generalized about the ankle due to significant ankle arthritis, rather than specifically located in the front of the ankle. In some instances, surgery to remove the bone spurs can contribute to an increase in a patient’s symptoms if it allows the ankle joint to move more and the ankle joint itself has significant arthritis.
The bone spurs themselves WILL tend to grow back over time. So recurrence of symptoms is not uncommon.