What is ankle impingement?
Ankle impingement can become a problem either at the front of the ankle (anterior) or at the back of the ankle (posterior). Dance, and ballet in particular, forces the ankle into a far end range position and the talus bone (top of ankle) can contact the tibia (bottom of shin) or soft tissues and capsule of the ankle and cause irritation.
Anterior impingement will occur in full dorsi flexion (ankle flexed) such as in a deep demi plie or repeated landing from jumps. The talus can make repeated contact with the tibia causing irritation. Small bony osteophytes are produced as a result and this leads to pain at the front of the ankle, a blocking sensation and a reduction in plie depth.
Posterior impingement will occur will full plantar flexion, or pointing of the foot. In an opposite mechanism to the above the talus has too much contact with the tibia at the back and causes irritation in this region. The presence of an os trigonum can also increase the changes of impingement. This is a small bone that has failed to fuse with the talus effectively during growth and can cause repeated compression of the ankle capsule. With such repeated chronic pinching the tissue will become thickened. Posterior impingement symptoms can also arise from tendons of FHL/FDL/Tib post as they pass behind the medial malleolus.
Symptoms Of Anterior And Posterior Impingement (Os Trigonum)
Anterior impingement feels like ankle pain at the front of the ankle that increases on full dorsi flexion. The ankle may feel weak and feel like it can’t be trusted to hold steady during routine activities. When anterior impingement comes from ligament irritation, pain and tissue thickening are usually felt in front and slightly to the side of the ankle. Tenderness and swelling may also be seen over the front of the ankle. There is often a sense of blocking and an inability to reach full plie depth.
Posterior impingement will be felt with full plantar flexion and activities such as tendu, rises and pointe work. The ankle will often feel weak and an inability to gain full range is often present. There is often a blocking sensation at the back of the ankle.
If we are dealing with an os trigonum or longer bone surface in the ankle there can be nothing to prevent this situation as it is structural. However, ensuring correct technique and effective foot strength and use, can help to minimise any symptoms. It is essential to have a screening if you have any sense of ankle pain to minimise the risk of swelling and resulting tissue thickening at the back or front of the ankle.