yogabook / pathology / ankle impingement syndrome, PAIS, AAIS

Definition of

Impingement of the ankle joint is a chronic pain syndrome caused by impingement of the talus on the tibia, which occurs primarily towards the end of the range of motion depending on the load. The first descriptions go back to Morris in 1943 and McMurray in 1950, who spoke of the footballer’s ankle. McMurray had discovered chronic ankle injuries in professional footballers that were painful in anterior dorsiflexion. In most cases, impingement is post-traumatic(supination trauma accounts for 85% of ankle injuries and 3-5% of all reported ankle injuries in the UK) or the result of excessive use of the joint in terminal positions. The overuse-related micro-injuries usually remain subclinical for a long time. In 15-20% of cases, those affected complain of chronic persistent or recurrent pain. The rate of supination trauma leading to anterior impingement is estimated at 3%; according to other figures, chronic pain develops in 20% of patients affected by one or more supination traumas, which is attributable to impingement in 30%.

Ankle impingement can be divided into 5 forms according to localisation. It mainly occurs anteriorly (AAIS) and less frequently posteriorly (PAIS). It also occurs less frequently anterolaterally; posteromedial and anteromedial localisations are rarer. Footballers, for example, are frequently affected with anterior impingement (Soccer Player’s Ankle), as the ball hitting the foot represents a major impact that abruptly forces the ankle joint into full-thickness plantar flexion.
plantar flexion, but also represents a localised trauma to which the ventral side reacts with thickening. Dancers who practise pointe dancing (en pointe position) are often affected by posterior impingement. There is no impact and the compressed dorsal side forms osteophytes.

Impingements are also frequently found as a result of
supination trauma. A less common cause is the presence of a Bassett ligament, which can lead to anterolateral soft tissue impingement. Posteriorly, less common causes include an oversized lateral processus posterius tali tuberosity or bones that deviate from the norm, such as an Os trigonum (Os trigonum syndrome). A distinction is made between soft tissue impingements with hypertrophy of soft tissues ( synovia, capsule, ligaments or scar tissue are trapped) and bony impingements with osteophytes or traction-induced bone spurs. The causes are genetically determined shape variants, an Os trigonum or Os subfibulare, overload-induced bone thickening such as osteophytes or free joint bodies. Bony changes usually appear first in the tibia and only then in the talus.

Clinically, chronic or recurrent pain dominates, often dependent on load and angle. Anterior pain manifests itself in examples with wide dorsiflexions such as when climbing stairs or ascending steeper terrain, posterior pain usually only with wide plantar flexion, which occurs less frequently in everyday life, most likely towards the end of the rolling phase when walking and running. Patients often feel a blockage, especially anteriorly during dorsiflexion in the anterior form, less frequently also dorsally during wide plantar flexion in the posterior form. As a rule, there is a reduced range of motion in the corresponding direction.

Cause

Anterior impingement:

The repeated direct trauma of high-energy ball contact on the ankle joint leads primarily to soft tissue impingement. The main causes of bony impingement are

1. more frequent forced dorsiflexion, resulting in the anterior edge of the tibia striking the neck of the talus, which forms traction spurs (traction-induced bone spurs).
2. Rotational instability of the talus resulting in bony pull-outs at the neck of the talus, fibula or medialmalleolus
3. Osteophytes due to arthrotic-degenerative processes of the joint
4. Insufficient height of the talus neck (the pathomechanism corresponds to the CAM impingement of the FAI)

Anterolateral impingement:

1. Plantar flexion-supination traumawith rupture of anterolateral ligaments, resulting in synovial inflammation, inflammatory changes, scarring and degenerative ligament hypertrophy. This allows entrapment in the anterolateral recess. In severe cases, a meniscoid develops in the recessus.
2. Basset ligament (from fibres of the anterior inferior tibiofibular ligament), which can become trapped in the ankle joint under certain circumstances such as ligament laxity.
3. Rare: Avulsion fractures of the ventrocaudal fibula
4. rare: ossified haematomas
5. Rare: Osteophytes

Anteromedial impingement:

1. Pronation trauma resulting in rupture of ventral fibres of the deep deltoid ligament
2. Plantar flexion-supination trauma with soft tissue changes and osteophytes on the dorsomedial talus shoulder, on the anteromedial distal tibia and on the anterior edge of the medialmalleolus. The osteophytes are usually associated with sport, usually football.
3. Post-traumatic ossicles, e.g. due to avulsions(capsule, anterior tibiotalar ligament)

Posterior impingement:

1. En-pointe and demi-pointe position in ballet resulting in compression of thetalus and neighbouring soft tissue structures between the calcaneus and tibia (nutcracker phenomenon, dancer’s heel).
2. Os trigonum due to failure of the ossification centre on the posterolateral talus to fuse with the corpus tali before puberty (7% of the population).
3. Particularly prominent tuberculum laterale processus posterioris tali (Stieda process).
4. Malleolus posterior (formanolia with extended posterior edge of the dorsocranial tibia).
5. Haglund’s exostosis.
6. Rarer causes lie in the soft tissues: Synovialitis (post-traumatic or sports overuse-related), synovial cysts, fibularis quartus muscle (variety), thickened capsule, post-traumatic thickened ligaments, stenosing tenosynovitis of the flexor hallucis longus tendon.
7. Incarceration of an existing posterior intermalleolar ligament (variant).
8. Hypertrophic flexor hallucis longus.

Posteromedial impingement:

Traumatic(supination trauma with plantar flexion and medial rotation)

Predisposing

– Behaviour

Dancing, ballet, cross-country skiing, football

– Health factors

1. Articulated flat foot
2. Hollow foot(anterior impingement)

Diagnosis

1. Radiological changes to soft tissue or bones
2. Click or snap
3. Pressure soreness

Symptoms

1. Movement- and load-dependent pain, for example when standing, more when walking, even more when exercising; in the anterior form, especially when climbing stairs and squatting.
2. Symptoms of the different forms:

anterior impingement: pain with wide dorsiflexion. Restricted dorsiflexion.

anterolateral impingement: pain intensification with supination or pronation. Occurrence of pain or its intensification with compression of hypertrophied synovial tissue between the talus and tibia. With Basset ligament: audible clicking on dorsiflexion and pronation.

anteromedial impingement: anteromedial pain that occurs or intensifies during dorsiflexion. Restriction of the range of motion in the direction of dorsiflexion and supination. Possibly soft tissue swelling.

Posterior impingement: posterolateral pain with or increasing with plantar flexion. Possibly swelling, tenderness between the Achilles tendon and the tendons of the fibularis.

Posteromedial impingement: posteriomedial pain that increases with plantar flexion and supination.

Complications

1. Recurrences are rather rare in the case of soft tissue impingements, but more frequent in the case of bony impingements, although clinically less pronounced.
2. If anterior impingement is due to instability, incongruence or osteoarthritis, the long-term results are often unsatisfactory.
3. Ankle joint arthrosis with corresponding previous damage, especially in the presence of osteophytes.

Therapy

1. Surgery: as far as possible, removal of trapped soft tissue; removal of enlarged bone. In posterior cases: regular mobilisation exercises on the patient’s own initiative despite perceived pain, in addition to PT.
2. Depending on the case, there are hardly any conservative treatment options other than soothing, primarily proprioception training, ankle-stabilising balance exercises, elimination of muscular imbalances and limited pronation ability as well as a lack of strength in the pronators. In the case of anterior impingement, a larger arch support (raised heel) can provide relief.