What is a posterior ankle impingement?
Posterior ankle impingement is usually the result of structures at the back of the ankle getting caught between the heel bone (calcaneum) and the lower leg bone (tibia). It causes pain at the back of the ankle, just above the heel bone, in activities where the foot is pointed down. It is commonly seen in dancers who spend extended time with toes pointed maximally (‘en pointe’), as well as in gymnasts, runners, kicking sports and fast bowlers in cricket.
Signs and Symptoms of a posterior ankle impingement
Posterior ankle impingement causes pain at the back of the ankle when the toes are pointed (plantarflexed) and when the structures mentioned above become impinged. This condition may sometimes also begin after a previous ankle sprain. In minor cases pain won’t be felt doing daily activities only high load activities such as dancing, however if the soft tissue around the impingement becomes inflamed general activities such as driving can become painful.
Causes of posterior ankle impingement
The cause of the impingement in this condition differs from person to person. Often the causes are soft tissue structures at the back of the ankle, such as the joint capsule and covering of the ankle (synovium), tendons and ligaments at the back of the ankle. In some people, the impingement may be due to a small extra bone in the back of the ankle called an ‘os trigonum’ that is present in about 10 per cent of adults. Having an os trigonum doesn’t guarantee that you will get this condition. Other people have a slightly more prominent bony point at the back of their bone in the ankle joint (talus), which can cause the impingement. Remember though, you may have the same features on your other ankle that are not painful and may not be clinically relevant.
Treatment for posterior ankle impingement
Rest – offloading from the aggravating activity, such as avoiding time en pointe or reducing kicking loads for a period. Medications may be advised to help settle any pain or associated inflammation if needed.
AlterG Anti-Gravity Treadmill – Continuation of training on the AlterG to decrease the load on the foot and its surrounding muscles whilst maintaining an exercise program.
Mobilisation and distraction techniques to the ankle joint that can help to settle symptoms and improve joint mobility. Strengthening exercises will be prescribed for the calf, as well as for any deficits identified further up the leg.
Taping – can be very effective in offloading the impingement. Appropriate footwear may also need to be considered to help management.
Assessment of technique – particularly in performance sports such as dancing or gymnastics. In ballet dancers, turning out of the foot while on toes may lead to the condition, and any issues should be identified and changed as part of rehabilitation.
Injection therapy – If pain persists, this may be considered or in cases where os trigonum is the causative factors, surgical removal may be considered.