Ligaments of the Ankle
Ligaments connect bone to bone and work hand in hand with the muscles and tendons to provide stability to any joint. There are two main ligament complexes in the ankle, the lateral ligament complex and the medial ligament complex.
What is a ligament?
A ligament is an organised bundle of collagen fibres intertwined to provide a stable connection between bones. The exact composition of the ligament will determine the level of elasticity, but mostly ligaments are quite tough. Ligaments have low vascularity, meaning that they have a slow capacity to heal.
An ankle sprain actually refers to partial or complete tearing of these ligamentous structures depending on the severity of the injury. The ligaments main job is to prevent movement of joints into inappropriate positions, and injury occurs when the forces are too great, resulting in the ligament being tensioned to its limits. In many joints, a way to compensate for this is to strengthen the surrounding muscles.
The Lateral Ankle Ligaments
The three main ligaments of the lateral ligament complex are:
- The anterior talofibular ligament (ATFL) – connects the front of the talus bone to the fibula (the shin bone on the outside of your leg)
- The calcaneofibular ligament (CFL) – connects the calcaneus (heel) to the fibula
- The posterior talofibular ligament (PTFL) – connects the back of the talus bone to the fibula
The ATFL is the most commonly injured ligament. The normal mechanism of injury for an ankle injury is when the foot is forced down and in (plantar flexion and inversion).
Ligament sprains are graded from 1 -3:
- Grade 1 – minimal tearing of ligament fibres
- Grade 2 – partial tearing of ligament fibres
- Grade 3 – complete tear or rupture of ligament
The grade is usually determined via several assessments by the physiotherapist as well as the level of pain, and ability to bear weight through the injured ankle.
Ligaments are also important for providing proprioception, information about where the joint is in space, meaning that once a ligament has been injured it is more likely to occur again. This reduced proprioception may lead to more commonly tripping and rolling the ankle. Balance training is an important method used to counteract the loss of proprioception.
The Medial Ankle Ligaments
The main ligament of the medial ankle is the deltoid ligament which spans most of the medial side. There is a deep and superficial layer to the deltoid ligament, meaning that it is quite strong, as both layers individually resist the foot turning outwards (eversion). This means that medial ankle sprains are far less common, but tend to be more severe as generally the injury has occurred with greater force. Injury to the deltoid ligament may also occur in conjunction with a high ankle sprain.
Another important medial ankle ligament is the Spring ligament (calcaneonavicular ligament), which plays a role in stabilising the medial arch of the foot. Acute injury may occur with forceful landing onto a flat foot, or injury can be commonly associated with the posterior tibialis tendon.
There is a multitude of tiny ligaments throughout the foot that help to ensure adequate stability for day to day function.
Anterior and Posterior inferior tibiofibular ligament (AITFL and PITFL) are the ligaments that support above the ankle, keeping the two shin bones stable over the ankle. To injure these ligaments, a larger force is often required pushing the foot into external rotation. Due to the location of these ligaments, the syndesmosis (connective tissue between the tibia and fibula) can commonly concurrently injured.
All in all, we know it is important to receive treatment for ankle sprains, as late diagnosis or lack of treatment can result in early onset arthritis!
If you are or know someone who is suffering from ankle pain, or has recently sprained their ankle, give us a call on 1800 992 999 or email us at [email protected] to book an appointment with one of our talented physiotherapists today!
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