Ankle impingement is a condition characterized by a painful mechanical limitation of joint movement. It occurs when soft tissue or bone is pinched between the ankle bones during normal motion, resulting in pain and stiffness. The condition is common, especially among athletes with repetitive ankle stress, and frequently develops following a prior ankle injury, such as a sprain.
Anatomical Classification and Impingement Types
Ankle impingement is classified based on the anatomical location of the mechanical blockage. The two primary locations are anterior (the front of the ankle) and posterior (the back). Anterior ankle impingement is the more common presentation, involving pain at the front of the joint that worsens when moving the foot upward (dorsiflexion). Conversely, posterior impingement causes pain at the back of the ankle, aggravated by pointing the toes downward (plantarflexion).
Beyond location, the condition is categorized by the type of material causing the obstruction: bony or soft tissue. Bony impingement occurs due to the formation of osteophytes, which are abnormal bone spurs developing on the edges of the tibia or talus. These bony growths reduce the joint space, leading to a painful block in movement.
Soft tissue impingement involves the pinching of non-bony structures, such as scar tissue, inflamed joint lining (synovium), or thickened ligaments. This often results from chronic inflammation or abnormal healing after an injury. The thickened tissue becomes entrapped between the articulating bones, and in the anterior region, it is frequently associated with recurrent ankle sprains.
Traumatic and Repetitive Causes
The development of ankle impingement is closely tied to trauma or sustained repetitive stress on the joint. A single acute traumatic event, particularly an ankle sprain, can initiate the condition. The initial injury causes bleeding and inflammation, and the subsequent healing process often results in the formation of scar tissue, contributing to soft tissue impingement.
Repetitive microtrauma is another significant cause, often seen in athletes whose sport requires extreme or repeated ankle movements. Activities demanding excessive upward motion of the foot, such as kicking in soccer or forced dorsiflexion in running, commonly lead to anterior bony impingement. The repeated stress causes minor damage to the cartilage, prompting the body to form protective osteophytes.
Posterior impingement is frequently seen in activities involving forceful and repetitive plantarflexion, such as ballet dancing or gymnastics. The presence of an os trigonum, an extra bone at the back of the talus (present in about 5% of the population), can make a person more susceptible to pinching when pointing the toes. The underlying mechanism involves an abnormal healing response that narrows the joint space.
Identifying Key Symptoms
The symptoms of ankle impingement are directly related to the mechanical obstruction and are aggravated by specific movements. Anterior impingement causes pain localized to the front of the ankle, intensifying during activities that require the foot to bend upwards, such as squatting, climbing stairs, or walking uphill. This pain results from the impinging structure being compressed during dorsiflexion.
For posterior impingement, the pain is felt deep in the back of the ankle and is provoked by pointing the toes down or performing activities like walking downhill or wearing high-heeled shoes. In both types, a sensation of catching or locking may be felt as the bone spur or thickened tissue momentarily gets trapped.
Chronic swelling and stiffness that persist long after an initial injury are common signs. The mechanical irritation causes ongoing inflammation, leading to a restricted range of motion. Tenderness to the touch is often present directly over the area of impingement, aiding in physical identification of the affected region.
Conservative and Surgical Management
Management of ankle impingement begins with conservative treatment methods aimed at reducing inflammation and pain. Initial interventions include resting the ankle, modifying activities to avoid painful movements, and using nonsteroidal anti-inflammatory drugs (NSAIDs) to manage swelling. Physical therapy helps restore the ankle’s range of motion and strengthens surrounding muscles to improve joint stability.
If initial measures do not provide sufficient relief, the next step often involves a corticosteroid injection delivered directly into the site of impingement. These injections reduce localized inflammation and are particularly effective in cases of soft tissue impingement. This conservative phase is pursued for a defined period before considering more invasive options.
Surgical intervention is generally reserved for individuals whose symptoms persist despite comprehensive conservative care. The procedure of choice is typically ankle arthroscopy, a minimally invasive technique using a small camera and instruments. The surgeon removes the impinging structures, such as bone spurs (bony debridement) or inflamed soft tissue. This arthroscopic clearance aims to restore the full, pain-free range of motion.