The ankle joint is a hinge between the leg and the foot. The bones of the leg (tibia and fibula) form a mortise, and the curved top bone of the foot (talus) fits between them. The talus is held to the tibia and fibula by strong bands of tissue (ligaments).
The ligament on the inside of the ankle (medial or deltoid ligament) has two layers; the deepest one is most important. This ligament is mainly torn in association with severe fractures of the ankle bones.
The ligament on the outside of the ankle (lateral ligament) is made up of three separate bands: one at the front (anterior talo-fibular ligament), one in the middle (calcaneo-fibular ligament) and one at the back (posterior talo-fibular ligament). The front band is usually the ligament injured in sprains or tears of the ankle ligaments, and the middle band is sometimes affected. The lateral ankle ligaments are more commonly injured than the medial.
The tibia and fibula have a small joint between them just above the ankle (distal tibiofibular joint). This also has strong ligaments, one at the front and one at the back (tibio-fibular ligaments). The ligament at the front is involved in about 10% of ankle sprains; the ligament at the back, is mainly damaged in association with severe fractures of the ankle bones.
How do they get injured?
Most ankle ligament injuries are caused by twisting injury of the ankle. This may stretch the anterior talo-fibular ligament causing partial or complete tear. If there is a major injury of the anterior talo-fibular ligament, the forces transfer to the calcaneo-fibular ligament and the tibio-fibular ligaments, which may also be torn. Occasionally small pieces of bone may be torn off with the ligaments (avulsion fractures).
In a few cases, a twisting force on the ankle may cause other damage. These include fracture of bones around the ankle, damage of cartilage in the ankle joint, and damage of tendons around the ankle.
What should I do if I sprain my ankle?
Most ankle sprains are fairly minor injuries, which will get better with simple measures. The RICE principle can be applied:
- Rest – take the weight off the injured joint as much as possible for a day or two;
- Ice – use an ice pack (a small bag of frozen peas or corn is ideal) for 10-15 minutes 3-4 times a day to reduce swelling;
- Compression – use a firm bandage or strapping to help getting the swelling down;
- Elevation – rest with the ankle above the level of the heart to reduce swelling.
Although a couple of days rest is useful, it is best to start taking some weight on the injured ankle soon after injury, usually within 2-3 days. It is also important to start to exercise and move the injured ankle as soon as possible after the injury, when comfort permits.
Normally a sprained ankle will recover within 6 – 12 weeks, although it may tend to swell for a few weeks longer. Most simple sprains get better without any special treatment. However, if you have a severe injury or the initial injury does not recover normally, it is usually best to see a physiotherapist. Physiotherapy will help settle down inflammation and strengthen the muscles on the outside of the ankle (peroneal muscles). This usually requires balance exercises undertaken with the help of a wobble board.
Will I keep having trouble with my ankle?
Most ankle injuries get better completely and cause no long-term problems. Sometimes, however, there is some permanent damage to the ankle. The ligaments may fail to heal properly and become weak, or there may be damage to the joint itself or some other structure nearby. This may result in pain and / or a feeling of instability of the ankle.
What can be done about ankle instability?
Physiotherapy using exercises to strengthen the muscles around the ankle and re-training proprioceptive nerves is useful. If the ankle and Achilles tendon are stiff, stretching exercises can be undertaken.
Many people will find their ankle will become much more stable and comfortable after physiotherapy. However, in some cases problems continue. At this stage, you should see an orthopaedic surgeon for further management. Your surgeon will take a history and examination of your ankle. You may require X-rays, ultrasound or an MRI scan.
Will I need an operation?
Most people with ankle instability will not need an operation. Even if your ankle still feels unstable after physiotherapy, bracing or strapping may be sufficient to allow a return to sport.
Surgery usually involves repair of torn or stretched ligaments. Surgery involves a cut on the outer side of the ankle and repair of the ligaments. An ankle arthroscopy may be performed at the same time.
You will be in a boot and on crutches for 6 weeks. Weight-bearing is not allowed through the operated leg for at least two weeks. Your mobility will be limited by swelling and discomfort. It is important that you rest in between walking to allow the pain and swelling to settle. At home, initially walking is kept to a minimum. You will require assistance with household chores such as cooking and cleaning.
After 6 weeks the boot is removed, it may take another 2 weeks to be comfortable in closed shoes.
Driving is not allowed when in the boot, but may be resumed when comfortable, particularly when you are able to brake in an emergency, usually at the 8 week mark following surgery.
Returning to work can be dependent upon the activities of your employment, but is usually resumed at anywhere between 6 weeks and 3 months following surgery.
Risks of Surgery
Risks of surgery include infection, wound healing problems (especially in those who smoke, have diabetes or vascular disease), stiffness, instability may recur over time or after an injury (especially in those who have generalised ligamentous laxity), blood clots (deep vein thrombosis and pulmonary embolism), damage to nerves and blood vessels leading to numbness.