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Impingement

Ankle impingement can occur on either the anterior or posterior ankle and may be due to bony or soft tissue causes (or both). Bone changes around the anterior ankle are commonly seen in footballers and may not necessarily be symptomatic. In these patients, routine XRs can show matching exostoses on the anterior margin of the tibia as well as the talar neck. It is thought that these are the result of repeated contact during extremes of dorsiflexion during kicking.

Posterior impingement can have a variety of causes. A prominent posterior process of the talus or os trigonum may predispose to this condition. Soft tissue causes of impingement include synovial hypertrophy, capsular injury, ligament injury and flexor halllicus longs (FHL) tenosynovitis or tendinitis.

 

History

Athletes with anterior impingement generally present with localised pain and tenderness of the anterior ankle. There will be pain (and generally reduced movement) with dorsiflexion. The athlete’s initial perception may be a loss of movement while stretching the calf. Footballers with posterior impingement describe pain at the back of their ankle when driving a ball from their laces – an activity that requires plantarflexion. Posterior impingement should be considered when the player complains of a sore Achilles tendon.

 

Examination

Patients with anterior impingement will have a loss of standing dorsiflexion and pain with forced ankle dorsiflexion. The most convincing clinical sign for diagnosing posterior impingement is pain felt in the posterior ankle with forced plantar flexion. In each condition there may be localised tenderness on either the posterior or anterior ankle.

Click on the following video to see how to assess for ankle impingement.

Click here to see how to assess for anterior impingement.

View how to assess for posterior impingement. Forced ankle plantar flexion should reproduce posterior ankle pain in patients with this condition.

Investigations

X-rays are often a very useful investigation. In cases of posterior impingement, one may see a prominent posterior process of the talus or os trigonum. A special view, called a lazy lateral, may demonstrate this more effectively. Bony changes around the anterior ankle may be seen on a lateral x-rays and may not be related to the player’s presenting pain. The athlete will generally have matching exostoses on the anterior margin of the tibia as well as the talar neck.

  • A lateral XR image showing evidence of bony impingement on the anterior tibia and talar neck.

  • A lateral XR image showing a large os trigonum.

  • A saggital MRI image showing increased signal within a large os trigonum.

Treatment

Both forms of impingement often resolve with avoidance of aggravating activity. Taping or bracing to prevent terminal dorsiflexion or plantar flexion can allow an athlete to remain active. A heel raise to facilitate ankle dorsiflexion is a good intervention in anterior impingement. Oral NSAIDs can be helpful. Steroid injections can provide very dramatic relief of symptoms if these other interventions fail. If symptoms are refractory to treatment, arthroscopic debridement can give a good result. It should be noted that in many cases the bone spurs recur after surgery, but the symptoms often do not.

Learn more about ankle impingement from the Aspetar Sports Medicine Journal.