What are the most common ankle injuries?
Perhaps one of the most common sports injuries, and also in the non-sporting population from a twist or fall is ankle ligament sprains. It’s common to sprain the ATFL on the outer side of the ankle, then slightly less common to sprain the CFL and AITFL ligaments. An injury to the AITFL is more problematic as it provides a lot of stability to the ankle joint and may require surgery. The ATFL and CFL ligaments can be managed conservatively. We can ultrasound scan the ankle to see which ligaments are injured and help to plan the course of rehab.
Ankle ligament sprains need to be managed well as they may cause at the time of injury, or are a risk factor for, an osteochondral defect on the talus bone (OCD). Ankle ligaments sprain can also lead to a condition called ankle impingement syndrome.
Management of ankle ligament sprains
Once a fracture has been rules out the initial management of an ankle ligament sprain is the RICE principles. Icing and compressing the ligaments to reduce bleeding and swelling is important in the initial 24-48 hours. Depending on the severity of the ankle ligament sprain it’s worthwhile using an aircast boot to immobilise the ankle and allow the area to start healing. A short period of partial weight bearing and crutches may be required, however we do want to encourage weight bearing as soon as possible. Using ultrasound guided PRP injections into the ankle joint in the early stage of injury management may also be useful. Physiotherapy is important after the initial few days so you can be guided through the stages of rehab you need to perform from gaining movement and strength to being able to hop, jump and change direction for high end sports activity.
What is an osteochondral defect of the talus?
Trauma is the most common cause of an osteochondral defect of the talus and results after a bad inversion sprain, or repeated ankle sprains from ankle instability. The talus is an interesting bone that has no muscular attachment and most of the bone is covered in a thin layer of cartilage which is susceptible to injury where it sits in the mortise of the tibia and fibula. When the ankle twists and the ligaments tear, it allows the lateral talus to bang into the fibula. The thin layer of the cartilage that covers the talus can easily tear and the lack of nerve supply in the cartilage means it is not painful, however the underlying bone oedema can be. At this stage you would probably need to have an x-ray or an MRI if your ankle sprain symptoms are not settling in the first month or two post injury.
Once you have imaging there are a number of clinical scenarios:
- An asymptomatic OCD – these are typically small OCDs, which are common, and they are generally managed by leaving them alone. There is no evidence it will lead to arthritis.
- Symptoms from another problem – there may be pain coming from anterior impingement which is also common post ankle sprain or in ankle instability.
- Mechanical symptoms from a cartilage tear flap leading to locking and catching in the joint and synovitis and swelling – this can be treated with micro fracture surgery.
- Deep bone pain from bone marrow oedema
Management of osteochondral defect of the talus
The first line of treatment is to correct alignment and strengthening with podiatry and physio respectively. Having a Biomechanical Gait Scan will help to establish if you need insoles for your shoes to correct your foot mechanics. Activity modification and rebab to resolve any weakness or ligament instability can also help as can anti-inflammatories if the ankle is painful. Alternatively, a PRP injection with or without hyaluronic acid may also be useful at settling pain and stimulating some tissue healing. Microfracture for small osteochondral lesions is a surgical procedure that can help to stimulate some new fibro cartilage growth in the area of injury, but as articular cartilage healing doesn’t take place and can lead to ongoing problems. Large lesions will require a more extensive surgical repair.
What is anterior impingement of the ankle?
Ankle impingement is an umbrella group of signs and symptoms associated with anterolateral ankle pain. Anteromedial and posterior impingement are less common. The first type of anterolateral impingement is associated with ATFL injury, the second one associated with the inferior AITFL. Impingement occurs secondary to an ankle sprain or recurrent sprains that leads to ankle instability, synovitis and fibrous / thickening of the ankle ligaments in the anterior lateral gutter. There is usually tenderness and localised swelling, and it is sore when the patient goes into dorsiflexion such as squatting or climbing stairs. Your physio might use a knee to wall test to establish anterior impingement.
Treatment includes physio for the ankle joint and strengthening to improve stability. It may be that you also take some anti-inflammatory medications to help as well. If this does not help that we would try an ultrasound guided steroid injection into the joint to settle the pain down.
Is the impingement caused by soft tissue or bone?
Anterior bone impingement is also possible, caused by osteophytes on the tibia and talus and impingement occurs from repeated ankle dorsiflexion. The bone spurs squash the soft tissues around the joint, so it is believed that impingement is a soft tissue problem.
Activity modification and ultrasound guided joint injection are useful initial treatment strategies for a bony impingement before surgery being required to remove the osteophytes.
What is posterior ankle impingement?
Posterior impingement is rare, it can occur with repeated plantar flexion such as kicking a ball or wearing high heels. The structures being impinged include the tendons that pass over the posterior joint such as the FHL tendon, the posterior joint capsule or from an os trigonum. This is also a soft tissue impingement, and it may also respond to physiotherapy such as settling inflammation, correcting mechanics and improving strength around the ankle. If this fails we would attempt an ultrasound guided steroid injection into the ankle joint which can be very useful in settling symptoms. Surgery to remove an os trigonum would be a last resort.