What is Impingement Syndrome of the Ankle?
Impingement syndrome of the ankle is a disorder caused by a spur of bone that has formed at the bottom of the shin bone at the ankle joint. As the foot is pointed skywards, the spur of bone can impact on the talus bone of the foot, or more commonly catch some of the lining of the joint like a pincer. This causes a nipping pain.
The foot points skywards during driving – for example taking pressure off a pedal. Nipping commonly occurs with running, limiting running distance. Sometimes, it occurs with walking alone. The pain is located at the front of the ankle joint, usually to the outer aspect of the front.
The spur is a reaction from the body to minor injuries to the ankle joint. This is frequently seen in sportspeople, especially footballers of all abilities. There may not have been one injury that can be remembered that caused the problem. A fracture of the ankle in the past may be related to a spur.
Sometimes, impingement can occur at the back of the ankle. This is commoner in individuals who spend a lot of time on tiptoes, such as ballet dancers.
If you have similar symptoms, it is best to see an orthopaedic surgeon who specialises in foot and ankle surgery. You should have x-rays taken in a standing position – this may demonstrate the spur.
How is the Surgery Performed?
The surgery is normally performed with a keyhole technique. This uses two incisions, only one centimetre long each, to insert a thin metal tube with a camera mounted on the end into the ankle joint.
The other incision is used to insert special shaving devices which can be used to remove scar tissue, loose cartilage and bony spurs which can contribute to the pain felt by patients.
There is a video below which shows different types of arthroscopic (keyhole) surgery.
Sometimes a further incision is made at the back of the joint to allow access to bony spurs at the back.
Surgery is carried out under general anaesthetic, but can be augmented with local anaesthetic injections behind the knee or around the ankle. The injections are normally given while you are asleep for your comfort. They can give good pain relief for the first day after the operation. You can go home the same day in the evening.
Risks of Surgery
Bleeding, infection, poor bone healing, poor skin healing, injury to tendons, injury to nerves, recurrence, and a need for further surgery.
There is a small risk of blood clots in the legs or lungs (DVT and PE), and there are also risks from anaesthesia – the process of being put to sleep for your operation.
Risks of Anaesthesia
The injection behind your knee is given using an ultrasound machine to guide the needle. There is a less than 1% chance of injury to the nerve. General anaesthetic also carries risks. These risks are proportional to your general health. You will need to be assessed for your fitness for surgery and an Anaesthetist will be able to advise you on your individual risk.
What Happens After Surgery?
You will have had injections to numb your foot so that you are not in pain after the operation. This injection will wear off after 18-24 hours, so you must take regular painkillers so that you are not in severe pain when the injection wears off. Ibuprofen and Diclofenac should not be used for more than a few days after the operation as they can interfere with bone healing.
The pain will settle over a few weeks. You may see blood stains on the dressings. This is normal and not a cause for alarm. If blood is dripping from the dressings however, return to hospital.
The ankle will be swollen as well as sore. You should keep the foot elevated as much as possible for the first two weeks. Keep walking down to a minimum – going to the toilet or for meals. Letting the leg hang down will cause the foot to become more swollen.
If you are resting on your sofa, keep your foot elevated on the back rest or arm rest. If you are resting in bed, then place a few pillows under the foot to keep it elevated.
You will not need a plaster cast or a plastic boot. You will have thick dressings which will stay in place for two weeks You can fully weight bear through the operated ankle, although this may be sore to begin with. The shoe is for your comfort when walking, and when the stitches have been removed, you can return to normal shoes.
Although any bony block to movement has been removed, you will initially not notice any change in your range of movement. This is because your Achilles tendon and other structures are still tight, and these need to be stretched through exercises to allow movement at the ankle to increase. After the stitches have been removed, and the pain is settling, you will need physiotherapy to stretch the structures behind the ankle. These stretches can be seen on the exercises page.
RETURNING TO WORK
You will have a sore ankle for at least a few weeks, and in some cases a few months. I recommend that you have at least two weeks off work with a possibility of requiring another four weeks if you are very sore from having bone shaved off the front of the ankle joint.
Some patients have recurrent pain around six weeks after surgery. This is due to inflammation and scarring around the ankle and may need an injection into the ankle to settle it down. Remember that not everyone is the same, and some people take a longer time to recover from their surgery. Please request a sick note before you leave hospital, if you need one.