Ankle ligament injuries

                              Ankle ligament injuries

                                                 Dr. KS Dhillon

Anatomy of ankle ligaments

The ligaments around the ankle can be divided into three groups: the lateral ligaments, the deltoid ligament on the medial side, and the ligaments of the tibiofibular syndesmosis which joins the tibia to the fibula.
1. There are three ligaments on the lateral side of the ankle that make up the lateral ligament complex. These include:

• The anterior talofibular ligament (ATFL), which connects the front of the talus to the fibula.
• The calcaneofibular ligament (CFL), which connects the calcaneus to the fibula.
• The posterior talofibular ligament (PTFL), which connects the rear of the talus to the fibula

2. The deltoid ligament supports the entire medial side of the ankle. It  has 2 components:
The superficial components which consist of:

• The tibiocalcaneal ligament,
• The talonavicular ligament
• The posterior superficial tibiotalar ligament
• The tibiospring ligament

The deep components which consist of:

• The anterior tibiotalar ligament (ATTL)
• The posterior deep tibiotalar ligament (PDTL)

3. The tibiofibular ligament (AITFL) connects the tibia to the fibula. It consists of:

• Anterior inferior tibiofibular ligament (AITFL)
• The posterior inferior tibiofibular ligament (PITFL)
• The inferior transverse ligament
• The interosseous ligament which extends from the tibia to the fibula. 

Ankle ligament injuries

The ankle is the most frequently traumatized body site and ankle injuries account for 10–30% of all sports injuries [1]. Ankle sprains are the most common musculoskeletal injuries and in all sports injuries, the rate of ankle sprains ranges from 15 to 20 % [2,3].

One inversion ankle injury occurs per 10,000 people every day which amounts to about 5000 injuries a day in the UK and about 23,000 in the US [4,5,6]. Most ankle injuries occurring during sports involve the lateral ankle ligament and this represents about 77% ankle sprains [1].

The most common mechanism of injury which leads to lateral ligament sprain or tear is a combination of inversion and adduction of the foot in plantar flexion [7]. This force injures the anterior talofibular ligament. When the inversion force occurs in a dorsiflexed ankle, the calcaneofibular ligament which is the primary stabilizer gets injured. Anterolateral rotatory instability occurs when the anterior talofibular ligament is injured and the medial ligaments are intact [8]. In addition to this, when the calcaneofibular ligament tears there is tilting of the talus [8].

Deltoid ligament injuries occur with eversion and external rotation. They are usually accompanied by fractures of the ankle [9].

Syndesmotic injuries result from forced external rotation during dorsiflexion and eversion movements of the ankle. Syndesmotic injury can occur in isolation or may be associated with ankle fractures [10].

Ankle ligament sprains are usually graded on the basis of severity of injury to the ligament [11].
In grade I injuries (mild sprain) there is a mild stretching of the ligaments without visible rupture or joint instability. The injury is usually limited to the ATFL.

 In grade II injuries (moderate sprain) there is a partial rupture of the ligament with moderate swelling and pain with functional limitations and a mild to moderate instability. Such patients typically present with problems in weight-bearing. In grade II injuries there is a tear of the ATFL with partial or complete tear of the CFL.

 In grade III injuries (severe sprain) there is a complete rupture of the ligament with marked pain, swelling, hematoma formation and a marked impairment of function with instability. This is the most severe type of injury where there is a tear of the ATFL and CFL and sometimes there is a tear of the capsule as well as a tear of the PTFL [12].

Although this classification is available and often used, there however remains clinical difficulties in quantifying the severity of these injuries.

Clinical evaluation

Patients will give a history of a twisting injury to the ankle. They will complain of pain, swelling of the ankle and of difficulty in walking.

Examination will show swelling, tenderness, and ecchymosis at the site of injury. There will be limitation of ankle movements and the walking pattern will be altered to avoid pain.

Grade I injuries will present with mild swelling, tenderness and minimal limitation of movements. In grade III injuries there will be diffuse swelling, ecchymosis, tenderness, ankle instability and inability to weight bear.

Pain, swelling, and tenderness on the medial side of the ankle with a soft tissue defect would denote a deltoid ligament injury.

Syndesmotic injury will present with tenderness over the anterior aspect of the syndesmosis and positive squeeze or external rotation test [13]. In all ankle injuries assessment of the neurovascular status is very important.

Stress testing is useful in the diagnosis of ankle ligament injuries if there is not much pain.

Useful stress tests include:

• Anterior drawer test: Anterior displacement of the talus over the tibia is carried out and displacement of more than 4mm denotes tear of the ATFL.
• Talar tilt test: A stress radiograph of the ankles is carried out by forced inversion of the ankle while the tibia is stabilized. A more than 5° of difference in outward shift as compared with the contralateral side denotes a CFL tear.
• Eversion stress test: Abduction with eversion of the ankle is carried out while the tibia is stabilized and increased laxity as compared to the opposite side denote deltoid ligament tear.
• External rotation stress test: Plantarflexion and external rotation of the ankle is carried out while the tibia is stabilized and the presence of pain and tenderness over the syndesmosis denotes syndesmotic injury.

Diagnostic studies

The usual first step following clinical examination after an ankle injury is obtaining x rays of the ankle. The Ottawa Ankle Rules (OAR) established by Stiell et al [14] help in decision making as to whether an x-ray is needed. According to the OAR, the following types of patients do not need x rays:

1. Patients who can weight-bear at the time of injury which means they are able to walk at least four steps, without assistance, two steps on the injured side and two on the other side, even if they are limping.
2. Patients are able to walk at the time of evaluation. This means walking at least four steps, without assistance two steps on each side, even if limping.
3.Absence of tenderness along the distal 6cm of the tibia or fibula (for ankle x rays).
4.Absence of tenderness on the proximal 5th metatarsal and navicular bone (for foot x-ray).


Initial ankle X-rays should include anteroposterior (AP), lateral and mortise views. AP and mortise views in dorsiflexion and plantarflexion can provide information about talar osteochondral lesions. If there is tenderness on the 5th metatarsal an oblique x-ray of the foot must be obtained.

Stress x-rays can be obtained to diagnose CFL tears. AP and lateral stress views with 20 degrees of internal rotation and valgus stress are useful in the diagnosis of deltoid ligament injuries.

On performing the valgus stress test a more than 10° of valgus tilt and/or more than 5 mm of widening in the medial clear space denotes syndesmotic injury. Other radiographic findings of syndesmotic injury include an increased tibiofibular clear space, decreased tibiofibular overlap and increased medial clear space [12].

Magnetic resonance imaging (MRI) is usually not indicated in patients with acute ankle injuries unless there is evidence of major ankle instability. MRI is often useful in patients in whom concomitant injuries such as osteochondral and tendon injuries are suspected. MRI may also be indicated in patients who have chronic ankle pain after an ankle sprain and in patients who have a clinical history of repetitive trauma and complex injuries of the ankle [12].

Treatment of ankle sprains

As with most injuries, prevention of injury is the best treatment. The best method of preventing ankle sprains remains controversial. Various types of footwear and bracing has been tried to prevent ankle sprains. Some have used low-top shoes combined with lace-up bracing while others have used high-top shoes with taping [15,16]. The use of taping has also been found to be of not much use in preventing ankle sprains [17].

The treatment of grade I and grade II ankle ligament injuries is quite straight with no controversy. The general consensus is that grade I and II injuries should be treated conservatively.
Almost all authors agree that patients who have a grade-I or grade-Il injury recover quickly with non-operative management [7,18,19,20] and that the prognosis is good or excellent in most patients [4,5,7,18,19,20,21,23,24,25].

Conservative treatment includes a short period of rest, ice, compression, and elevation (RICE) followed by protective taping or bracing and functional rehabilitation [18].

There are 4 stages of biological healing in ankle ligament injuries and functional rehabilitation treatment is based on these four stages.

In the 1st stage, there is inflammation and swelling and RICE protocol helps reduce inflammation and swelling [26]. In the 2nd phase, there is healing and proliferation with fibroblasts forming collagen fibers. In this phase bracing or taping is needed to prevent talar tilt [27]. The 3rd phase is the maturation phase when the collagen fibers mature and become scar tissue. This phase starts at about 3 weeks after the injury. Controlled stretching is started which allows reorientation of collagen fibers which prevents stiffness [28].

The 4th and final stage of healing occurs between 6 to 8 weeks following the injury. At this stage, the patient returns to near full strength and can return to full activity. Full recovery can take up to 6 to 12 months [28].

Functional rehabilitation involves ankle mobilization, muscle strengthening and improving proprioception. A stationary bicycle can be used for increasing range of motion. Tilt board and trampoline can be used to improve proprioception [28]. Nonsteroid anti-inflammatory medications and cryotherapy have only short term benefits.

The average disability period for grade I injuries is about 8 days and the average disability period for grade II injuries is about 15 days [23].

Treatment of grade III ankle sprains is less standardized and more controversial. Good results have been reported for grade III ankle ligament tears with acute surgical repair, cast immobilization, and also with functional rehabilitation.

Kannus and Renstrom [30] were one of the earliest authors to conclude that functional treatment is the preferred method for treatment of complete tears of lateral ligament. Their findings have since been corroborated by other researchers [31,32].

Kannus and Renstrom [30] carried out a review of 12 prospective studies
and found that functionally treated patients returned to work 2 to 4 times faster than those who had acute repair.

Kaikkonen et al [33] carried out another comparative study and reported excellent to good outcomes in 87% of functionally treated patients as compared to surgically treated patients where only 60% of patients had good to excellent outcome. Furthermore, the range of ankle movements at final follow up was less in patients who had surgery.

Munk et al [34] carried out a prospective study to compare the long term outcome of three methods of treatment of lateral ligament injuries. The methods of treatment included, operation and walking-cast for 5 weeks, walking-cast alone, and elastic bandage. They followed up the patients for an average period of 11 (9-13) years. They found that the residual disabilities and late complications, such as instability, pain on activity, talocrural arthrosis and the number of ligament reconstructions were equally low in all 3 groups. They concluded that nonoperative treatment is adequate for lateral ligament tears.

Surgical repair of acute ankle ligament tears is rarely performed. There are some proponents of acute repair for lateral ankle sprains. Leach and Schepsis advocated primary repair of grade III tears in young athletes with Grade III sprains [35]. A study by Pijnenburg et al [36] found better objective scores in patients who had surgical repair of the ligament but they concluded that in most patients surgery was not worth the additional cost, risks, and complications.

Surgery is not indicated in the acute setting and if any late instability develops, the instability can be treated by surgery with a similar outcome as with a primary repair [30].

Kerkhoffs et al [37] carried out a Cochrane systematic review to find out if primary surgical repair of the torn ankle ligament gives a better result as compared to conservative treatment. They concluded that there was not enough evidence from randomised controlled trials to show that surgery gives a better result than conservative treatment for acute ankle sprain in adults.

Complications

Risk of reinjury

Attenborough et al [38] carried out a systematic search of the literature to determine the presence of common aspects of chronic ankle instability (CAI) within individual sports. They found that in volleyball the incidence of recurrent sprains was 46%, in American football 28%, in basketball 19% and in soccer the incidence was 11%. Other researchers have found the incidence of recurrent sprains to vary from 12% to 47% [39,40,41,42,43].

A history of lateral ankle sprain is one of the strongest risk factors for a future lateral ankle sprain [44,45,46].
Future injury-prevention interventions must keep in mind the risk for
subsequent injury after an initial ankle sprain.

Chronic ankle instability(CAI)

The high reinjury rates after an acute lateral ankle sprain are associated with the development of CAI. CAI is characterized by ongoing pain, giving way and feelings of instability in the ankle. This leads to persistent disability when the instability interferes with daily activities. Chronic ankle instability can develop after an acute ankle sprain, from multiple injuries to the same ligament.

Chronic ankle instability can be due to mechanical instability, functional instability, or a combination of both. Mechanical instability can be due to pathologic laxity, arthrokinematic changes, synovial irritation, or osteoarthritis. Functional instability is usually caused by insufficiencies in proprioception and neuromuscular control [47].

A recent review of CAI by Gribble et al [48] suggested that up to 70% of individuals who sustain an acute lateral ankle sprain may develop CAI over a short time period following the initial injury.
Doherty et al [49] in a prospective cohort study found a 40% CAI prevalence rate at one year after a first-time lateral ankle sprain.

CAI prevalence is higher in individuals who participate in running, jumping, and cutting activities. Individuals who participate in dance and gymnastics have a higher prevalence of CAI than other sporting populations [38,48].

CAI is treated with nonoperative measures such as peroneal strengthening, lateral heel wedges, proprioceptive training, and strapping or bracing [28]. Patients who have functional instability without demonstrable mechanical instability will benefit from these non-operative measures. Patients with mechanical instability who do not respond to conservative treatment over a period of about 6 months can be treated with surgery.

Surgery for CAI can be carried out by an anatomic repair, nonanatomic reconstruction, or an anatomic reconstruction of the lateral ligament.

Brostrom first described the technique of an anatomic mid-substance repair of the ATFL and CFL in 1966 [50]. In Broström’s anatomic repair, midsubstance imbrication and suture of the ruptured ligament ends is carried out.

Gould et al [51] modified the Brostrom procedure. They reinforced the repair using the lateral talocalcaneal ligament and the inferior extensor retinaculum to correct the subtalar instability. Karlsson et al [52] imbricated the damaged ligaments and reinserted the ligaments through drill holes in the fibula.

Over the years several non-anatomic reconstruction methods have been described. The first was by Elmslie in 1934. Elmslie used a fascia lata graft to reconstruct the lateral ankle ligaments [53].

Watson-Jones in 1952 popularised the use of the peroneus brevis tendon to reconstruct the lateral side of the ankle by rerouting the tendon in a posterior to anterior fashion through the fibula and securing it onto the talar neck [54].

Evans in 1953 reported a simplified modification of the Watson-Jones procedure where he routed the peroneus brevis tendon obliquely through the distal fibula in an anterodistal to the posterioproximal fashion [55]. Chrisman and Snook [56] modified the original Elmslie procedure. He split the peroneus brevis tendon and transferred one portion of the tendon through the fibula and into the calcaneus, thus providing a much more anatomic reconstruction.

Anatomic reconstructions can augment anatomic repair without sacrificing lateral ankle kinematics. Colville used a split peroneus brevis tendon to augment a repaired ATFL and CFL. In this anatomic reconstruction, the peroneus brevis is placed into the anatomic origins and insertions of the lateral ligaments. As a result, normal ankle kinematics and subtalar motion are maintained [57]. In anatomic reconstructions, free autograft or allograft tendons such as the gracilis, fascia lata, plantaris, palmaris, and semitendinosus can also be used. This technique is indicated in patients with poor tissue quality and for revision surgery.

Posttraumatic Osteoarthritis 

Posttraumatic osteoarthritis (PTO)  is one of the more serious complications of ankle sprains. The incidence of PTO after lateral ankle sprains varies between 13% to 22% and 80% of ankle PTO cases are due to ankle sprains [48]. Besides ankle sprains, the other causes of ankle PTO include fractures and osteochondral lesions [58].

Fifty percent of the PTO develop after a single acute sprain and the other 50% develop as a result of recurrent sprains [48].

A retrospective study by Valderrabano et al [58] showed that the overall mean latency time for symptomatic end-stage ligamentous posttraumatic ankle osteoarthritis was 34.3 years (range, 6-57 years). They also found that ankles that were treated surgically a shorter mean latency time as compared to those who were treated nonoperatively.

In a 20-year follow-up study, Lofvenberg et al [59] found a 13% incidence radiographic OA in patients CAI. 

Canale and Belding [60] found a much higher incidence of posttraumatic OA in patients with CAI. They found an incidence of 48% at 11 years follow up.

The presence of degenerative changes on arthroscopic examination of the ankle are higher with reports demonstrating degenerative changes in 21% to 95% percent of patients with CAI [ 48].
The exact aetiology of these degenerative changes has not yet been established. Taga et al [61] carried out preoperative arthroscopy of the ankle in 31 patients before ligament operation. Nine patients had a fresh injury, and 22 patients had chronic injuries. They found chondral lesions in 89% of the freshly injured ankles and 95% of the ankles with chronic injuries. The authors were of the opinion that acute LAS may be sufficient to cause an osteochondral lesion. These findings could explain why patients with a single episode of ligament injury can develop post-traumatic osteoarthritis
.
There is a scarcity of literature on the interaction of symptoms with documented degenerative changes in the ankle following LAS. Van Ochten et al [62] carried out a study to look at the correlation between degenerative changes in ankle and symptoms. Their study included 206 patients who had an ankle sprain 6 to 12 months before the study. The patients filled up a standard questionnaire and had a physical examination, x rays and MRI of the ankle. Of the 206 patients, 98 had persistent complaints of pain and 108 did not have any complaints. There were no significant differences in structural abnormalities between patients who had symptoms and those who did not have any symptoms. In both groups, many structural abnormalities were found on x rays and MRI. X rays showed OA in the talocrural joint in 45.1% of patients and 36.5% of the patients had talonavicular sclerosis. On MRI bone oedema was seen in 33.8% of the patients and talocrural osteophytes in 39.5% of the patients. Talonavicular osteophytes were seen in 54.4%, sclerosis in 47.2%, and osteoarthritis in 55.4% of the patients. They also found anterior tibiofibular ligament damage in 16.4% of the patients.

They concluded that the prevalence of structural abnormalities is high on radiography and MRI in patients with a previous ankle sprain and there is no difference in structural abnormalities in patients with and without persistent complaints. They were of the opinion that imaging alone will not provide the explicit reason for the persistent complaints after LAS.

Conclusion

Ankle sprains are the most common sporting injury (15% to 20% of all sporting injuries). Seventy-seven percent of all ankle sprains involve the lateral ligamentous complex. Approximately 20 percent of acute ankle sprains result in functional or mechanical instability leading to chronic ankle instability.

Diagnosis is made through a thorough history and a good clinical examination. Radiographs and MRI are useful for excluding other associated pathologies.

There are 3 grades of ankle sprains. Grade I and II sprains are always treated conservative. Treatment of grade III sprains is more controversial. The consensus is that grade III sprains should be treated conservatively in the acute phase. Late instability with persistent symptoms can be treated surgically. Anatomical repairs are most commonly used for the treatment of symptomatic chronic instability of the ankle.

Complications after ankle sprains are not uncommon. There is a high risk of re-injury after ankle sprains, especially in athletes. Other disabling complications include chronic ankle instability and posttraumatic OA.

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