mri scan ankle instability ligament

What is Ankle Instability? What causes Recurrent Sprains?

When most people sprain their ankle, they make a slow but sure recovery over the course of a few months to return to normal activity. Sometimes, ankles do not return to normal and recurrent ankle sprains occur. This can be so frequent that it occurs several times every day. This is associated with pain, swelling and an inability to take part in normal day to day activities and sport, with loss of confidence.

ankle instability pain osteochondral injury

Sprains normally result in stretching of a ligament, but the ligament remains in continuity. If the ligament is torn, it may join together with scar tissue. If the ligament/scar tissue is stretched enough, it is unable to prevent excessive movement of the ankle joint and the feeling of instability ensues. Often, patients have spasm of muscles on the outer side of the ankle as they attempt to compensate for the excessive movement by pulling hard with a tendon.

In about a quarter of cases, recurrent sprains are not due to ligament injury, but damage within the ankle joint. This can lead to pain and swelling and sudden pain can lead to giving way of the ankle. 

If you have ankle instability, 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. Sometimes this can demonstrate damage inside the joint, but often an MRI scan is performed to demonstrate damage to ligaments and to the surface of the joint.

ankle instability ligament

How is Surgery Performed?

The operation is composed of three parts. Firstly, the ankle is examined clinically and with x-rays while you are asleep. Secondly, a keyhole examination of the ankle is made as up to one quarter of ankle instability is caused from within the ankle joint. Thirdly, if the first two parts suggest that it is required, the ligaments on the outside of the ankle are tightened.

ankle instability osteochondral damage cartilage injury

If the ligaments are tightened then you will have a plaster cast applied, and this will stay on for six weeks. If the ligaments are not tightened, then you will be able to walk on the foot as pain allows. If it is felt that the ligaments do not need tightening, but instability continues, then this part of the operation may need to be performed subsequently.

incision for ankle instability brostrum procedure

Surgery is carried out under general anaesthetic, but can be carried out 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.

postoperative shoe foot surgery

What Happens After Surgery?

The rehabilitation you require depends on how much surgery was done. You may have had just the ankle arthroscopy if a cause was found inside the ankle, or you may have had the ligaments tightened. If you have had just the arthroscopy, you will not be in plaster. You may walk on the ankle straight away, unless you are specifically told not to weight bear for six weeks if a cartilage  operation was performed to encourage the joint to repair. If you had the ligaments tightened, then you will be in plaster and not able to weight bear for six weeks.

plaster cast brostrum ankle instability
If ligaments tightened

PAIN

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.

aircast boot ankle instability
If ligaments tightened

SWELLING

The foot 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. Most of the swelling will settle within the first few months, but swelling can continue for up to one year.

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.

WALKING

You will normally be in plaster for a total of six weeks after surgery for ligament rupture. During this time, you should not weight bear on this foot. You will need crutches or a walking frame to get about.

Two weeks after the operation, you will have your plaster removed, and the stitches removed. You will then have a further plaster applied for four more weeks. After this, you will have an xray and if this is satisfactory, you will be given a removable plastic boot, in which you can put your weight through the operated foot. You will use this for a further six weeks. This can be removed for washing, performing exercises and at night.

BLOOD CLOTS

If you are in plaster for a prolonged period, you will be at risk of developing a blood clot in your leg. You will be given injections to thin the blood to cut this risk down. These can be self-administered, even in the elderly. You can stop taking these as soon as you progress to a plastic boot.

EXERCISES

While you are in plaster, you can perform exercises to keep the leg muscles above the knee strong, as these will become weaker as you are not weight bearing.

You can remove the plastic boot to wash, and perform exercises depending on your operation. You will also start physiotherapy at this point.

After twelve weeks, you will be seen in the clinic. From this time, you will start to wean yourself off the plastic boot and will wear a smaller brace for three further months.

RETURNING TO WORK

You will be unable to weight bear while in plaster. I advise that you do not return to work before the plaster is removed, especially if you are on your feet all day at work. Most people will be off work for four months as a minimum, but if you have a workplace with disabled access that allows you to use crutches and you are sitting down most of the day, you may be able to return to work while wearing the plastic boot. 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.