What is posterior ankle impingement?
Posterior ankle impingement, also known as posterior impingement syndrome, is the medical term used when repetitive compressive forces cause damage to the soft tissue at the back of the ankle. The ankle joint is made up of one strong capsule that forms around the joint, encapsulating it and preventing either boney ends of the lower leg and foot from connecting or impacting. The ankle is, in fact, made up of two joints in order to allow it a lot of movement and flexibility. The point where the lower leg connects to the foot is through the tibiotalar joint (the joint between the tibia and the talus). This joint allows the foot to point downwards and upwards. Pointing downwards, known as plantar flexion, compresses the ankle at the back and is the action responsible for most posterior ankle impingements. The second joint is the subtalar joint (the joint between the talus and calcaneus), this joint allows the ankle to bend from side to side. The two joints are encompassed by the one strong capsule. The capsule itself is filled with a small amount of thick fluid called synovial fluid that acts like a cushion. In addition there is protective layer of articular cartilage that covers each boney surface. The cartilage, fluid and strong capsule allow the joint to move in a smooth, flexible manner. Ligaments that surround the joint are made of thick, tough, fibrous tissue that overlap the joint and work in co-ordination with the strong lower leg muscles to provide protection and stability for the ankle. As you can see, there are a lot of soft tissue structures at the back of the ankle that may be injured.
Why & when does posterior ankle impingement happen?
Posterior ankle impingement is a common injury and effects people of all ages. It is normally seen in individuals who partake in sports that involve repetitive or forceful plantar flexion of the foot, such as football, gymnastics and ballet dancing. The forceful and repetitive compression at the back of the ankle, between the boney surfaces of the tibia and talus, entraps the soft tissue of the ankle joint. This causes small amounts of damage and inflammation of these structures with each compression. Certain anatomical variants or dysfunction with the foot or ankle joint may leave you slightly more at risk of developing posterior impingement syndrome, as does hypermobile ankles. Often cases of ankle impingement are seen after an acute injury to the ankle, such as an ankle sprain.
What does posterior ankle impingement feel like?
Posterior ankle impingement can cause a very intense, immediate, sharp pain or dull ache around the back of the ankle when plantar flexing your foot. In some cases the discomfort is only felt on plantar flexion during an activity and with others it is felt once resting after such an activity. Stiffness and dull aches are normally experienced during the night and are most intense early in the morning. The pain and discomfort is not always restricted to the back of the ankle and is often reported to radiate up into the calf muscle or down into the foot. On occasions there may be minor swelling around the back of the ankle, this is normally only experienced after a long period or repetitive plantar flexion, for example after a football match or ballet recital.
How long does posterior ankle impingement take to heal?
Mild cases of posterior ankle impingement can recover in as little as one to two weeks. More moderate or severe ankle impingements take longer. However as long as the aggravating plantar flexion activity has been avoided during recovery then most impingements will have fully healed within six weeks. If you experience pain for longer than six weeks it is advisable to see your GP.
How will posterior ankle impingement be diagnosed?
Your GP or Therapist will be able to diagnose you by both listening to your history and examining you. Occasionally an ankle X-ray or further investigation may be needed to confirm diagnosis and rule out any complicating factors.
What treatment options are available for posterior ankle impingement?
Your GP will most likely prescribe anti-inflammatory medication and painkillers to reduce any swelling and pain relief. You will be advised to follow the R.I.C.E protocol. The R.I.C.E protocol involves: Resting your ankle, try not to walk about on it too much and most importantly avoid all plantar flexion movements. Ice, applying a covered ice pack to the area may also significantly hasten the healing process by reducing the pain and swelling. Make sure the ice pack is covered to prevent any ice burn and for best results use the icepack use regularly for 10-15 minutes with intervals of 30 minutes. Compression, try and keep the elastic bandage on during the day to limit the swelling and make sure to take it off at night. Elevation, keep your foot raised on cushions or a stool to help limit the swelling.
Your GP or therapist will be able to provide you with exercises to strengthen the ankle ligaments and muscles to aid the healing process and prevent reoccurring injury. Many people find manipulative therapies such as physiotherapy, chiropractic and osteopathy to help through mobilisation treatment of the ankle as it works to reduce the severe stiffness levels and return the joint back to its normal movement.
If you feel or your GP has mentioned that there is any foot or ankle dysfunction that has predisposed you to this injury then it is very important that you see a podiatrist who can fully check whether or not your foot needs extra support through orthotics for your shoes. The failure to do this may result in recurring cases of ankle impingement.