Anterior Talo-Fibular Ligament (ATFL)
The Anterior Talo-Fibular Ligament (ATFL) is one of three ligaments that make up to Lateral Collateral Ligament of the ankle. The ATFL is a short ligament that widens slightly from top to bottom.
The function of the ATFL is to resist inversion and plantar flexion of the ankle joint. Injury to the ATFL usually occurs when the athlete's center of gravity is shifted over the lateral border of the weight-bearing leg, causing the ankle to roll inward at a high velocity. The ATFL is the weakest of the lateral collateral ligaments and therefore the first to be injured.
Mechanisms of injury may include landing awkwardly on an opponent's foot, catching the outer aspect of the foot on the ground terrain, or a slide tackle that contacts the inside of the opponent's weight-bearing leg.
Ankle ligamentous sprains are the most common single type of acute sport trauma. Ankle ligament sprains were also reported to be the most common injury for college athletics in the United States. The anterior talofibular ligament is the most commonly injured ligament in the ankle.
When a patient presents with a possible ATFL injury, a full physical evaluation should be performed:
- Observation: Observe for gross abnormalities, edema, ecchymosis, and perform a neurovascular assessment.
- Palpation: Palpate for areas of tenderness over the ATFL as well as other lateral collateral ligaments. Check the dorsal pedal pulse, capillary refill, and sensation to light touch. Edema can be measured by using a tape measure to make a figure-8 measurement that encompasses the medial malleolus, lateral malleolus, navicular, and base of the fifth metatarsal.
- Range of Motion: Bilateral goniometric measurements should be taken of active and passive ranges of motion.
- Special Tests:
- Anterior Drawer Test: While stabilizing the tibia and fibula with one hand, use the other hand to hold the foot in 20° of plantar flexion while the talus is drawn forward in the ankle mortise. The Anterior drawer tests the integrity of the ATFL and the anterior joint capsule. A positive test result is when there is greater than 5 mm of anterior motion of the STJ as compared with the non-injured ankle. An audible clunk may also be present during test. Due to increased pain and swelling acutely, the anterior drawer test has been found to have a markedly increased sensitivity when performed 4 to 5 days after injury.
- Talar Tilt Test: This test is primarily performed to determine the integrity of the calcaneofibular ligament (CFL), however, can also give valuable information about the ATFL. The test is performed with the ankle held in neutral position while the talus is tilted into adduction and abduction. Repeat the test with the foot in plantar flexion to evaluate the integrity of the ATFL. A positive test result is 5° to 10° of increased inversion as compared with the non-injured ankle, indicating a CFL injury.
- Swelling observed distal to the lateral malleolus of the ankle that may extend to the foot if the lateral capsule is torn.
- Tenderness palpated over the ATFL and, in more severe cases, the CFL.
- The anterior drawer and the talar tilt test may reveal joint laxity due to tearing of the ATFL and/or the CFL ligament.
- Stress radiographs may reveal excessive anterior translation of the talus or inversion of the talus.
Classification of Lateral Ankle Sprains:
- Grade 1: Small tear of the ATFL. Symptoms include minimal swelling and point tenderness directly over the ATFL, little to no instability, and the patient is able to ambulate with little to no pain.
- Grade 2: Large tear of the ATFL. Symptoms include a broader region of point tenderness over the lateral aspect of the ankle, a painful gait or inability to ambulate, bruising and localized swelling due to tearing of the anterior joint capsule, ATFL, and surrounding soft tissue structures.
Ottawa guidelines should be used to determine if radiographs are required:
- Tenderness over the medial malleolus, lateral malleolus, navicular, and/or base of the fifth metatarsal upon palpation;
- An inability to weight bear immediately following injury or during the clinical evaluation;
- Tenderness that extends 6 cm superiorly from either malleolus
If gross abnormalities are present, radiographs should be performed immediately. Standard radiographic views include anterior to posterior, lateral, and ankle mortise.
Acute Inflammatory Phase
Physiotherapy should be initiated to aid in the normal healing process as well as to protect the ligament from further injury.
Grade 1 and 2 Sprains:
- Rest or Modified Activity- weight-bearing as tolerated
- Ice- Ice therapy applied for 20 mins on/1 hour off throughout the day to reduce pain, edema, and secondary hypoxic damage to the injured tissues.
- Compression- A semirigid orthosis, lace-up style brace, or tape may be used to help provide support.
- Medications (Nonsteroidal anti-inflammatories) as well as electrical stimulation (TENs), pulsed ultrasound, antiedema massage and low-level laser may help in reducing inflammation.
- Active Range of motion (ROM)- patient should be instructed to perform ankle pumps (10 to 20 an hour) within a pain-free range in order to decrease inflammation and increase circulation.
- Soft tissue techniques- Active Release Techniques, Graston Technique, muscle energy techniques, and transverse friction massage applied directly to the ligament and surrounding soft tissue structures can be used to aid in early ligament healing.
Grade 3 Sprains:
If upon initial examination, a patient is unable to bear weight and displays significant ankle pain and swelling then suspicion of a grade 3 sprain must be warranted. The patient should be placed in a functional walking orthosis and instructed to be non weight-bearing and ambulate using crutches. Patient should then be instructed to perform RICE protocol (Rest, Ice, Compression, Elevation) until MRI can be performed.
- Reduce inflammation
- Joint mobilization/Passive stretching: Restore active and passive ranges of motion
- Strength Training
- Maintain cardiovascular fitness
- Proprioceptive rehabilitation
- Advanced strength training
- Agility Training
- Multi-directional sports-specific proprioceptive training
- Bonnel FT, Toullec E, Mabit C, Tourné Y. Chronic ankle instability: biomechanics and pathomechanics of ligaments injury and associated lesions. Orthopaedics & traumatology: Surgery & research. 2010 Jun 1;96(4):424-32.
- Dubin JC, Comeau D, McClelland RI, Dubin RA, Ferrel E. Lateral and syndesmotic ankle sprain injuries: a narrative literature review. Journal of chiropractic medicine. 2011 Sep 1;10(3):204-19.
- Fong DT, Chan YY, Mok KM, Yung PS, Chan KM. Understanding acute ankle ligamentous sprain injury in sports. BMC Sports Science, Medicine and Rehabilitation. 2009 Dec 1;1(1):14.
- Kumai T, Takakura Y, Rufai A, Milz S, Benjamin M. The functional anatomy of the human anterior talofibular ligament in relation to ankle sprains. Journal of anatomy. 2002 May;200(5):457-65.
- Clinically Relevant Technologies. Available from: http://www.youtube.com/watch?v=Z4rvAT3a7OY. [Last Accessed: 21 October 2020
- The Physio Channel. How to do the Talar Tilt Test for the ankle. Available from: https://www.youtube.com/watch?v=dp7usAmLl5c [Last Accessed: 21 October 2020]