Ankle: Anterior and Posterior Impingement Syndrome

An ankle impingement occurs when there is pain in the ankle joint during exercise or sports where there is repeated and extreme dorsiflexion or plantarflexion of the foot about the ankle joint (sometimes called the “talocrural joint”) when it is loaded. The particular type of tissue stress involved in this pathology is always due to a compression force. When someone has ankle impingement syndrome, they will experience pain at the end ranges of movement of the ankle joint, which is often restricted.

The term “ankle impingement syndrome” covers several underlying pathologies due to both acute and chronic (meaning repetitive) trauma to the ankle, and is therefore quite common. It can involve either soft-tissue or bony impingement, or both, and can be anterior or posterior.

Most people who develop ankle impingement syndrome are active and take part in sports. Football in particular puts people at a high risk of anterior ankle impingement.

The ankle joint is formed by the lateral malleolus of the fibula and the medial malleolus of the tibia, with the distal tibial plafond articulating with the proximal surface of the talus lying between them, created a hinge joint. Please see the image below, as this may make this description clearer.

In addition to the structure of the bones that make up the ankle joint, a set of ligaments and connective tissues give the joint stability and coherence. Please see the images below for more details.

Medial View of the Talocrural Joint Ligament Complex (often called the “Deltoid Ligament”)
Lateral View of the Talocrucal Ligament Complex
Posterior View of the Talocrural Ligament Complex

An anterior-lateral ankle impingement (meaning an impingement at the front and to the outside of the ankle) is due to soft-tissue lesion of the anterior-inferior tibiofibular ligament or the anterior talofibular ligament. Both the AITF and ATFL are often injured during sports and symptomatic scar tissue can develop around these ligaments in about 2% of cases, causing what is called a “meniscoid lesion”. This lesion is essentially a mass of hylanised tissue that is formed following a lateral inversion injury of the ankle. This mass can become trapped between the fibula and talus, causing impingement and pain.

Anterior ankle impingement (which means on the front of the ankle) is due to abnormalities in the bone tissue and results from repetitive microtrauma between the central part of the anterior tibial plafond and the neck of the talus. Osteophytes may develop in the joint space and progressively reduce the amount of dorsiflexion available in the joint (dorsiflexion is the movement you’d have to make to pull your toes up towards your face if you were looking down on them). This condition was once often called “Footballers Ankle” and it is common in people who play football, but is also common in people who do others sports or athletic activities, such as dancing, especially ballet. Changes in the bone can be accompanied by inflammation and scarring of the joint capsule, which worsens the condition.

Anterior-medial ankle impingement (which means on the front and inside of the ankle) usually occurs around the anterior aspect of the medial malleolus. It is believed that one or more ankle inversion injuries can damage the anterior tibiotalar ligament (part of the Deltoid Ligament), or cause small fractures or contusions (bruises) of the bone, resulting in osteophytes developing in the area, causing anterior-medial ankle impingement.

Posterior-medial ankle impingement (which means the back-inside part of the ankle joint), involves structures in and around the posterior-medial recess. The posterior-medial recess is formed from the posterior part of the medial malleolus and posterior tibiotalar ligament, the adjacent cartilage and the medial part of the posterior talar process. If that sounds confusing, here an image to show the area. Notice the proximity of the Tibialis Posterior and Flexor Hallucis Longus tendons.

The Posterior Medial Recess

If an ankle injury involves high plantarflexion, inversion, and internal rotation forces, this can produce a medial compression injury, leading to inflammation and scar tissue in this area as well as osteochondral lesions of the talus and/or malleolus, which is believed to occur in as many as 2 out of every 3 cases. Pathologies of the Tibialis Posterior and Flexor Hallucis Longus tendons can also be involved.

Posterior impingement is due to an enlarging of the posterior aspect of the talus or to an os trigonum (an accessory bone that develops in adolescence and only in some people and not everybody). Both will reduce the ability of the ankle to plantarflex, possibly leading to pain due to impingement during plantarflexion, as well as soft-tissue inflammation and scar tissue in the area.

Posterior-lateral ankle impingement is produced by a meniscoid lesion, as it is in anterior-lateral impingement. This happens following an ankle injury and associated lesions on the posterior-lateral ligaments. This is a rare condition and not often seen in practice.

Patients presenting with an anterior or posterior ankle impingement usually have a history of ankle injury followed by a pain at the end of a reduced range of dorsiflexion or plantarflexion of the joint. The patient will often be able to point out the exact location of the pain. Patients usually take part in sports, most often football or ballet, which are common causes of these injuries. Patients may also report stiffness and “popping” or “snapping” noises coming from the ankle joint. Swelling is not always present and the area may be tender to palpate.

A diagnosis is made from a history of the condition, presenting symptoms, palpation of the anterior and posterior-medial aspects of the ankle (the posterior-central and posterior-lateral are not directly palpable). Using anterior and posterior ankle impingement tests can ellicit pain at the end of the range of motion and serve as a means to confirm the diagnosis. X-ray imaging can be helpful to confirm any bony pathology such as osteochondral lesions, os trigonum, or bone spurs. Ultrasound can be helpful to determine if there is any intra-articular effusion and tenosynovitis (which means fluid build-up in the joint space and inflammation of the fluid-filled sheath around the tendons in the local area – remember the Tibialis posterior and Flexor hallucis longus in posterior-medial ankle impingement?). MRI is perhaps the best form of imaging for this condition, but the cost is often prohibitive when other less-expensive methods can be used. CT scans are reserved for detecting small bone lesions or avulsions, and for preparing for surgery.

Conservative treatment is the first option to explore when managing this condition, including rest, immobilising the joint, and possibly orthoses, heel raises, or other functional devices in-shoe devices or footwear changes. Changing how the person exercises for a period of time, often several weeks, is often required, and using NSAIDs is often recommended to relieve pain during recovery. Corticosteroid injections and acupuncture can also be used to reduce pain and inflammation, albeit with potential side-effects including erosion of bone, tendon, and joint cartilage. Acupuncture can also be used to reduce pain and inflammation, and is far less likely to cause side-effects than steroids, but may take several sessions to produce signficant results. Surgery may be required to remove space-occupying lesions and/or bone tissue.

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