The ankle joint (talocrural joint) is a synovial hinge joint that connects the distal tibia and fibula with the proximal talus, allowing mainly flexion and extension motion, but also some rotation, supination and pronation. The bony arch formed by the articular surface of the tibia (plafond) and the medial and lateral malleoli is a rectangular socket referred to as the ankle “mortise.” The articular surfaces are covered by a thin layer of hyaline cartilage. Owing to its bony architecture, the ankle joint is more stable in dorsiflexion than in plantar flexion. This means that almost all ligament injuries happen in plantar flexion.
The ankle joint is stabilized by several extra-articular ligaments. These can be divided into three groups: 3
Lateral collateral ligament complex.
Medial (deltoid) ligament.
Syndesmotic ligament complex.
The lateral collateral ligament complex is composed of three distinct parts originating around the lateral malleolus: the anterior talofibular ligament (ATFL), the calcaneofibular ligament (CFL), and the posterior talofibular ligament (PTFL). Similarly, the syndesmotic ligament complex also has three distinct parts, giving axial, rotational, and translational stability to the distal tibia and fibula: the anteroinferior tibiofibular ligament (AITFL), the posteroinferior tibiofibular ligament (PITFL), and the interosseous tibiofibular ligament. The interosseous membrane also adds to the stability of the syndesmosis. In contrast, the medial ligament is a single unit that consists of two layers: the superficial and deep layers.
Anteriorly, the tendons of the anterior muscle compartment of the lower leg pass under the extensor retinaculum, together with the superficial and deep peroneal nerves and the dorsal pedal artery. Posteromedially, the posterior tibial and long toe flexor tendons are located with the posterior tibial artery and the tibial nerve. The peroneal tendons are located posterolaterally, behind the lateral malleolus, and posterior to the ankle joint is the Achilles tendon.
7.3 Clinical Examination
Ankle injuries can often be easily diagnosed with the aid of a thorough patient history and a systematic clinical examination. The examiner should be able to identify the following:
If there was player contact when the injury occurred or beforehand.
If the foot was free or planted on the ground.
If the player felt a “snap” or “pop” when the injury occurred.
If the player was able to continue playing or had to leave the pitch.
Asking for details of any previous ankle injuries or ankle surgery is often helpful.
The clinical examination of an ankle injury should consist of the following:
Evaluation of range of motion (ROM).
Muscle strength tests.
Other ankle-specific tests.
7.3.1 Visual Inspection
During the visual inspection, the examiner needs to look for gait disturbance, swelling, a hematoma, muscle hypotrophy, lower limb malalignment, etc.
Note: The visual inspection should always be carried out with the patient walking, standing, sitting, and lying down.
7.3.2 Evaluation of Range of Motion
The typical active ROM for a footballer is approximately 10 to 15 degrees of dorsiflexion and 45 to 50 degrees of plantar flexion. The value of additional passive ROM testing is limited if the player has a pain-free and symmetrical active ROM. Comparison with the other side is always necessary.
7.3.3 Muscle Strength Tests
Muscle strength should be evaluated against resistance. This is usually done manually by the examiner, but hand-held dynamometers or other strength testing devices might be of value in some cases.
Always begin the palpation in areas where you have a low suspicion of injury. Important anatomical structures to palpate include the joint line, the ligaments, and the posterior parts of the malleoli—as well as the Achilles tendon, including its insertion, and the base of the fifth metatarsal bone. It is important that the fibula and the interosseous membrane are palpated from the ankle to the proximal tibiofibular joint to identify or rule out any concomitant injury higher up.
7.3.5 Laxity Tests
In contrast to the knee, there are only a few manual laxity tests for the ankle joint. However, as with the knee, it is extremely important to compare the laxity with the nonaffected side.
Lateral Collateral Ligament Complex
The lateral ligaments are evaluated using the anterior drawer and talar tilt tests. The anterior drawer test is used to assess the ATFL, while the talar tilt test is used to assess both the ATFL and the CFL.
Anterior Drawer Test
With the patient supine and the knee flexed at 20 degrees, the examiner holds the hindfoot with one hand and places the other hand on the distal part of the lower leg and moves the talus forward in the ankle mortise ( ▶ Fig. 7.1). During testing, the anteroposterior translation and the quality of the endpoint (firm, soft, or absent) are evaluated. The test is considered positive if the anterior drawer motion is at least 5 mm more than that seen in the contralateral healthy ankle.
Fig. 7.1 Anterior drawer test.
Talar Tilt Test
In the talar tilt test, the patient sits with the knees flexed at 90 degrees ( ▶ Fig. 7.2). While the distal tibia and fibula are stabilized with one hand, inversion stress is applied to the ankle with the other hand cupped under the heel. The test is considered positive if the talar tilt is 20 degrees or more, or if it is at least 10 degrees more than that seen in the contralateral healthy ankle.
Fig. 7.2 Talar tilt test.
The ankle eversion stress test is commonly used to assess the integrity of the deltoid ligament. Laxity testing of the medial ligament is usually more difficult to carry out and interpret than for the lateral ligaments.
Eversion Stress Test
The patient sits with the knees flexed at 90 degrees ( ▶ Fig. 7.3). While the distal tibia and fibula are stabilized with one hand, eversion stress is applied to the ankle with the other hand cupped under the heel.
Fig. 7.3 Eversion stress test.
Syndesmotic Ligament Complex
The stability of the inferior tibiofibular joint, especially the AITFL, is commonly evaluated using the external rotation test (Kleiger’s test) and the squeeze test.
External Rotation Test
In the external rotation test, the patient lies supine with the foot in a neutral position ( ▶ Fig. 7.4). The lower leg is stabilized and the examiner passively rotates the foot externally. The test is regarded as positive if this maneuver elicits pain at the site of the AITFL.
Fig. 7.4 External rotation test.
In the squeeze test, the patient lies supine with the feet in a neutral position ( ▶ Fig. 7.5). The examiner firmly and slowly squeezes the tibia and fibula together just above the AITFL. The examiner holds it for a few seconds, and then quickly releases the pressure. If there is pain from the AITFL upon release, the test is considered positive, indicating an AITFL injury.
Fig. 7.5 Squeeze test.
Note: Laxity testing and evaluation can be difficult in an acute setting because of pain and swelling. It is usually better to wait until 4 or 5 days after the injury before conducting laxity tests.
7.3.6 Other tests
It has been reported that Achilles tendon ruptures are overlooked in up to 20% of patients in a general setting. 4 Consequently, the Thompson (or Simmonds–Thompson) test should always be included in the routine clinical examination of the ankle region, as should tests for anterior and posterior ankle impingement.
During the Thompson test, the patient lies prone with the feet over the edge of the examination table ( ▶ Fig. 7.6a, b). The examiner flexes the knee approximately to 20 to 30 degrees to unload the gastrocnemius muscle and then squeezes the midportion of the calf muscle from side to side. The normal response to this maneuver is plantar flexion of the foot/ankle, while a lack of plantar flexion is considered a positive Thompson test, indicating a total rupture of the Achilles tendon.
Fig. 7.6 (a) Thompson test: normal reflectory plantar flexion with intact Achilles tendon. (b) Thompson test: no movement of the foot in case of ruptured Achilles tendon.
Testing for anterior impingement requires the ankle to be quickly moved—passively—from a neutral position to hyperdorsiflexion. The test is considered positive if the player experiences sudden pain anteriorly. Similarly, for posterior impingement, forced hyperplantar flexion will elicit ankle pain posteriorly. The posterior impingement test should be done with the knee flexed in order to uncouple the gastrocnemius muscle.
7.4 Radiological Examination
A significant ankle injury should always be referred for at least a standard radiographic examination in order to rule out a fracture and identify any osteochondral lesions or loose bodies inside the joint. Magnetic resonance imaging (MRI) is highly sensitive, allowing occult skeletal injuries, articular bone marrow lesions, and cartilage lesions to be observed, as well as soft tissue pathologies such as tears in ligaments and tendons. In experienced hands, ultrasonography can also be used to examine the ligaments and tendons around the ankle joint, for instance injury to the peroneal tendons.
Stress radiographs play no role in the routine diagnosis and care of acute ankle sprains, but may occasionally be used in the investigation of chronic functional ankle instability. It should, however, be borne in mind that there is little correlation between the findings of stress radiographs and symptoms of functional instability.
7.5 Ankle Sprains
Distraction injuries to the stabilizing connective tissue around the ankle joint (i.e., the joint capsule and the ligaments) are very common, resulting from both contact and noncontact injury mechanisms. Ligament injuries are often roughly categorized as either partial or complete tears; this classification usually has a prognostic value, with complete tears leading to longer layoffs in general, but rarely needing surgical treatment. Ankle sprains used to be the most common football injury, 5 but the injury rate has fallen considerably over the last 20 to 30 years and appears to be continuing to decline. 6 This is probably due to successful implementation of research on the football field, i.e., increased knowledge among medical practitioners about preventive measures.
7.5.1 Lateral Ligament Injuries
Epidemiology and Diagnostics
Lateral ankle sprains are the single most common ligament injuries in football, accounting for around 7 to 8% of all injuries in professional football and half of all ankle injuries. 6, 7 This means that a male elite team can expect three to four lateral ankle sprains per season ( ▶ Fig. 7.7a, b). Many lateral ankle sprains occur as a result of player contact, often involving tackling or foul play. 8, 9 A football-specific injury mechanism involving a direct impact on the medial aspect of the lower leg by an opponent tackling before or at the point of foot strike, resulting in forced inversion of the ankle joint, has been well described. 9
Fig. 7.7 (a) Typical injury mechanism for lateral ankle sprain. (b) Typical injury mechanism for lateral ankle sprain. (Image by Tommy Bolic, used courtesy of Oslo Sports Trauma Research Centre/Tommy Bolic. Image originally published in Andersen et al 2004 9.)
Fig. 7.8 (a) Rupture of the anterior talofibular ligament. (b) Rupture of the calcaneofibular ligament. (c) Rupture of both ligaments, the ankle joint is rendered unstable. (These images are provided courtesy of Annette Dahlström.)
Lateral ligament sprains are often divided into three categories on the basis of their severity (see ▶ Table 7.1). This classification is mainly of prognostic value.
ATFL tender, with minimal swelling and no increase in laxity
ATFL and CFL tender, with swelling, restricted ROM, and some increase in laxity
ATFL, CFL, and PTFL tender, with marked swelling, severely restricted ROM, and significant increase in laxity
Abbreviations: ATFL, anterior talofibular ligament; CFL, calcaneofibular ligament; PTFL, posterior talofibular ligament; ROM, range of motion.
It is important that a careful clinical examination is carried out in all cases, even if the diagnosis appears to be obvious. This is because there are several differential diagnoses that need to be considered, including fractures of either the lateral malleolus or the posterior process of the talus, bony avulsions of the base of the fifth metatarsal bone, osteochondral/cartilage injury, as well as a partial (longitudinal) rupture or dislocation of the peroneus brevis tendon. A delayed clinical examination after 4 to 5 days (or a second examination at that point) is often of higher quality and more reliable than an earlier examination. 11
Note: A twisted ankle is not always a sprain, and a systematic clinical examination should always be conducted to rule out other—sometimes more severe—soft tissue (or bone) injuries in the ankle region.
Treatment and Return to Play
In an acute setting, the most common treatment is rest, ice, compression, and elevation (RICE), although the scientific evidence for this is limited. 12 Most sports medicine practitioners advocate early mobilization, with an accelerated rehabilitation program, regardless of the amount of ligament involvement and the degree of laxity. 13 With appropriate immediate treatment and early mobilization, almost half of all professional footballers can return to full activity within approximately 1 week following a lateral ankle sprain. 6
Short-term immobilization in an acute setting—and even acute ligament repair—might be considered for a small minority of players. Some players have concomitant associated joint injuries, such as osteochondral injuries and/or loose bodies, and might need arthroscopic surgery. Moreover, a minority of players develop functional instability, which might require surgical reconstruction if rehabilitation is not successful. These players usually have positive anterior drawer and talar tilt tests and repeatedly experience the ankle giving way. The primary surgical technique is anatomical ligament reconstruction (which involves imbricating and reinserting the damaged ligaments, sometimes reinforcing them with local tissue such as periosteum, or the extensor retinaculum), followed by a short period of immobilization (10–14 days in a plaster cast being the recommended period, followed by 4 weeks of ROM training using an ankle brace) and physical therapy. 14 A player can usually return to football within 3 months following reconstructive surgery.
The prognosis after a first-time ankle ligament injury is usually good, and most footballers can return to play quickly, often with the use of an ankle support (taping or bracing) for at least 2 to 3 months (or until the end of the season). Reinjuries used to be common, 5 but they are less of a problem today, with only around 10% of all lateral ankle sprains in professional football recurring within a few months of the player returning to football. 6, 7 This is probably a result of the successful adoption and implementation of various secondary prevention strategies, such as balance board training and bracing/taping. 15, 16, 17, 18