Endgames Case Review

Management of ankle injuries

BMJ 2015; 351 doi: https://doi.org/10.1136/bmj.h6698 (Published 15 December 2015) Cite this as: BMJ 2015;351:h6698
  1. Matthew Welck, senior fellow in foot and ankle surgery1,
  2. Michael Rafferty, orthopaedic specialist registrar1,
  3. Stephanie Eltz, orthopaedic specialist registrar1,
  4. Shafic Said Al-Nammari, specialist registrar2,
  5. Kelechi Chika Eseonu, trauma and orthopaedic registrar 3
  1. 1Department of Orthopaedics, Wexham Park Hospital, Slough, UK
  2. 2Department of Trauma and Orthopaedics, Barts and the London NHS Trust, London, UK
  3. 3Department of Orthopaedic Surgery, John Radcliffe Hospital, Oxford, UK
  1. Correspondence to: M Welck matthewwelck@doctors.org.uk

A 26 year old woman presented to the emergency department after injuring her left ankle. While walking on an uneven pavement in the rain she lost her footing and described a sudden “buckling” of her ankle (plantar flexion and inversion injury). She could not bear weight so an ambulance was called.

She was previously fit and well and was on no regular drugs. Six months earlier she had twisted the same ankle while playing hockey. Radiographs taken at the emergency department had been normal, and she was discharged with crutches and a compression bandage. She returned to work after two weeks but had not returned to sport because she did not trust her ankle.

Clinical examination identified tenderness, swelling, and ecchymosis over the anterior talofibular and calcaneofibular ligaments, with some bony tenderness on the posterior edge of the lateral malleolus. She had no medial tenderness. Ankle ligament stress testing was not performed owing to pain.

Questions

  • 1. What is the most likely diagnosis?

  • 2. What are the other possible diagnoses after this mechanism of injury?

  • 3. What relevant history and examination are needed?

  • 4. How should she be investigated?

  • 5. How should she be managed?

  • 6. What features warrant specialist referral in patients with ankle sprain presenting to general practice?

  • 7. How should she be followed up?

Answers

1. What is the most likely diagnosis?

Short answer

Lateral ankle ligamentous injury.

Discussion

The most common injury sustained during an ankle plantar flexion and inversion injury is a lateral ankle ligamentous injury. The bony architecture of the ankle joint is most stable in dorsiflexion. Ankle sprains are therefore more likely to occur with the ankle in plantar flexion because ligamentous support is more important.

A 2014 meta-analysis found a higher incidence of ankle sprain in females than in males, in children than in adolescents, and in adolescents than in adults. Indoor and court sports were the sport category with the highest incidence of ankle sprain in the United Kingdom.1

The lateral ligaments comprise the anterior talofibular ligament (ATFL), the calcaneofibular ligament (CFL), and the posterior talofibular ligament (PTFL) (fig 1). Injuries tend to occur in a stepwise fashion. Because the ATFL is injured first it is the most commonly injured. In more severe injuries the CFL is also damaged and then the PTFL, which is rarely damaged.

Figure1

Fig 1 Lateral ligaments of the ankle

Lateral ankle ligament injuries are graded 1, 2, or 3 (fig 2),2 3 according to the degree of damage to the ligament(s). Grade 1 represents a sprain or stretch, usually with mild tenderness and swelling, minimal pain on bearing weight, and a normal stress examination. Grade 2 represents an incomplete tear, with moderate tenderness, swelling and ecchymosis, some reduction in range of motion and ability to bear weight, and some laxity to stress examination. Grade 3 represents a complete tear, with severe swelling (can extend >4 cm above the fibula), ecchymosis, inability to bear weight, and positive stress examination (if possible to test).

Figure2

Fig 2 The three grades of lateral ligament injury

2. What are the other possible diagnoses after this mechanism of injury?

Short answer

Ankle fracture, anterior calcaneal tuberosity fracture, fifth metatarsal fracture, syndesmosis injury, ankle osteochondral injury, and peroneal tendon injury.

Discussion

Other possible diagnoses after an inversion and plantar flexion injury include:

  • Ankle fracture—Inversion (or supination) of the ankle can cause a spectrum of ankle fractures, including a fibula fracture, which results in lateral sided tenderness and inability to bear weight. The spectrum of ankle fractures that can be sustained during a supination injury is well described in the Lauge-Hansen classification.4 The first part of the classification refers to the position of the foot at the time of injury (supine or prone). The second part refers to the subsequent force on the foot (external rotation, abduction, or adduction). Several stages for each type of ankle fracture are described. The Danis-Weber classification (also known as the Weber classification) is another common method of describing ankle fractures. The three categories are based on the level of the fibula fracture. Weber A describes a fibula fracture distal to the syndesmosis, B is at the level of the syndesmosis, and C is proximal to the syndesmosis.5

  • Calcaneus fracture—Fracture of the anterior process of the calcaneus presents with lateral ankle pain and pain on palpation inferior to the lateral malleolus. It can usually be seen on a lateral radiograph of the foot, although a computed tomogram may be needed.6

  • Fifth metatarsal fracture—These fractures can also be sustained with inversion or supination injuries. Pain is usually felt over the lateral border of the foot, especially on bearing weight. These fractures occur in three zones. Zone 1 is an avulsion injury from the proximal tubercle and heals well. Zone 2 is at the meta-diaphyseal junction and is in a vascular watershed region so is prone to non-union. Zone 3 is diaphyseal and also has a high rate of non-union.

  • Ankle osteochondral injury—Osteochondral defects affecting the talar dome may be purely cartilaginous or involve bony fragments as well. These may easily be missed. If purely cartilaginous they will not be seen on radiography. Talar dome lesions occur in 6.8-22% of ankle sprains.3 7 8

  • Peroneal tendon injuryPeroneal tendon or retinaculum tears are classically caused by sudden dorsiflexion of an inverted foot, leading to a rapid reflexive contraction of the peroneus longus and brevis tendons. Swelling and tenderness are often noted posterior to the lateral malleolus and there is often apprehension with active dorsiflexion and eversion against resistance. Peroneal tendon injuries can cause ankle instability.9 10

  • Ankle syndesmotic injury (“high ankle sprain”)—Injury to the tibiofibular syndesmosis occurs with external rotation injuries, which force the talus to rotate laterally and push the fibula away from the tibia. They are therefore not strictly a differential diagnosis in this case, but should be mentioned in an article on ankle sprains. They represent about 0.5% of all ankle sprains. The syndesmosis joins the tibia to the fibula and comprises the anterior-inferior tibiofibular ligament, posterior-inferior tibiofibular ligament (strongest component), transverse tibiofibular ligament, interosseous membrane, interosseous ligament, and inferior transverse ligament (fig 3). Disturbance of the integrity of the ankle mortice may lead to joint incongruence and arthritis. The outcome is excellent if the syndesmosis is anatomically reduced. Isolated syndesmotic injuries are rare and are normally associated with bony injury, particularly high fibula fractures known as Maisonneuve injuries (fig 4).11

Figure3

Fig 3 Components of the syndesmosis

Figure4

Fig 4 Maisonneuve-type fracture, with proximal fibula fracture, syndesmosis disruption, and medial ligament injury

3. What relevant history and examination are needed?

Short answer

History must include details of the injury, current symptoms, and previous injuries. Examination comprises “look, feel, move, special tests.” The anterior drawer and talar tilt tests assess the lateral ligamentous complex.

Discussion

History must include:

  • Time since injury

  • Exact mechanism of injury

  • Details of any other mechanism of injury. For example, eversion, forced severe plantar flexion, or dorsiflexion should raise suspicion of an unusual ligamentous injury or fracture

  • Location of pain

  • Any locking or feeling of loose bodies in the ankle joint (may suggest displaced osteochondral injury)

  • History of ankle sprains and instability (such as difficulty walking on uneven surfaces).

Examination should comprise “look, feel, move, special tests.”

On inspection there is usually swelling and ecchymosis anterior to the distal fibula. Gross deformity should raise the suspicion of a fracture. Occasionally, marked swelling can give the false impression of a deformity.

Systematically palpate the ATFL, CFL, PFTL, distal fibula, peroneal tendons, fifth metatarsal base, anterior joint line, and proximal fibula. Pain along the talotibial joint line raises the suspicion of an osteochondral talar dome lesion.

Document the comfortable range of motion of the ankle in dorsiflexion and plantar flexion.

Special tests in ankle inversion injuries include:

  • Assessment of gait—Assessment of the ability to bear weight. Patients will typically display an antalgic gait.

  • Anterior drawer test—This assesses the integrity of the ATFL. The patient should sit with the knee flexed to relax the gastrocnemius-soleus complex and the ankle plantar flexed by 10º. The heel is held and forcefully pulled forward with one hand while applying proximal counter pressure with the other hand. Severe anterior subluxation compared with the uninjured ankle suggests damage to this ligament (fig 5).

Figure5

Fig 5 Anterior drawer test to test integrity of anterior talofibular ligament

  • Inversion stress test or talar tilt test—This assesses the integrity of the CFL. The patient is again positioned with the knee flexed. The heel is grasped and the talus is tilted into varus. The findings should be compared with those of the contralateral side. The normal degree of tilt is 0-23º (fig 6).

Figure6

Fig 6 Talar tilt test to test integrity of calcaneofibular ligament

  • Squeeze test or Hopkin’s test—A positive test result indicates injury to the syndesmosis. It is performed by compressing the fibula and tibia at the midcalf. It is considered positive if pain is elicited over the syndesmosis.12

  • External rotation test—This is performed by stabilising the leg proximal to the ankle joint while grasping the plantar aspect of the foot and rotating the foot externally. If painful, it may signify an injury to the syndesmosis.12

In many instances pain precludes proper examination during the acute period and repeat clinical examination is indicated once the pain and swelling have subsided, generally after two weeks.

4. How should she be investigated?

Short answer

Because she was unable to bear weight and had bony tenderness at the posterior edge of the lateral malleolus, radiography of the ankle is warranted.

Discussion

The Ottowa ankle rules are well established evidence based guidelines to determine the need for radiography in ankle inversion injuries (fig 7).13 14 15 These rules are almost 100% sensitive for detecting fractures in adults and children as young as 5 years and 40% specific. Negative findings therefore eliminate the need for radiography but positive finding do not prove there is a fracture. Application of the rules reduces the proportion of unnecessary radiographs by 36%.

Ankle radiography (anteroposterior, lateral, mortice (15º internal rotation)) is indicated if there is pain in the malleolar region of the ankle, with either:

  • Bony tenderness over the posterior edge of the lateral or medial malleolus (areas of potential fracture). The posterior edge is specified because purely ligamentous injuries may have tenderness on the anterior edge of the fibula, or

  • An inability to bear weight for four steps immediately after the injury.

The radiograph should be assessed for ankle fracture, talar osteochondral defects, widening of the syndesmosis, and talar tilt.

Foot radiography is indicated if there is pain in the midfoot zone with either:

  • Bony tenderness over the base of the fifth metatarsal or navicular, or

  • Inability to bear weight for four steps.

Other investigations are rarely indicated in the acute investigation of ankle inversion injuries.

Full length lower limb radiographs (including the knee) are indicated if a syndesmosis injury is suspected. A proximal fibula fracture may indicate a Maisonneuve-type injury.

Ankle stress views (images taken with a varus or valgus stress applied to the ankle or with gravity applying the stress) may help detect injury to the syndesmosis not apparent on plain films or ligament insufficiency in the setting of recurrent sprains. The sensitivity and specificity of stress view radiography are similar to that of magnetic resonance imaging (MRI) for detecting for ligamentous injury, and this technique allows for more dynamic and functional assessment.16 17

Computed tomography may be used to help identify or delineate a fracture (for example, fractures of the ankle, fifth metatarsal, navicular bone, or calcaneal anterior tuberosity).

MRI may be used to identify or delineate a talar osteochondral defect,18 syndesmosis injury, or peroneal tendon injury. MRI has 98% sensitivity in detecting syndesmotic disruption.18 19 It can also help identify bone bruising, which may be responsible for persisting pain.

Figures 8 and 9 show the patient’s radiographs.

Figure8

Fig 8 Anteroposterior radiograph of the patient’s ankle

Figure9

Fig 9 Lateral radiograph of the patient’s ankle

5. How should she be managed?

Short answer

She may need a boot or brace, cryotherapy, elevation, and analgesia initially. Encourage weight bearing and start range of motion exercises when pain allows, progressing to concentric and eccentric strengthening, proprioceptive training, and sport rehabilitation.

Discussion

The fundamental principles in managing ankle sprain are to encourage early weight bearing and instigate range of motion exercises as soon as pain allows.9 20 21

Such a programme can often be started immediately in grade 1 and 2 injuries but may need to be delayed in a grade 3 injury. It has been shown to be superior to prolonged rest, with respect to time to return to work or sport, long term ability to return to sport, long term ankle instability, and patient satisfaction. Early motion and weight bearing stimulate the formation of stronger replacement collagen.

The first (immediate) phase of treatment may involve temporary immobilisation and compression, ice, elevation and analgesia.2 3

A painful, swollen sprained ankle tends to be held in a plantar flexed and slightly inverted position and quickly stiffens when in this position. Furthermore, tissues tend to contract after trauma. If this occurs, rehabilitation has to be delayed until the stiffness is overcome. Therefore, a device that holds the ankle in a neutral position for the early period, but that can easily be removed to permit cryotherapy, may be used. An air stirrup brace or boot (fig 10), or a lace-up support, is more effective than an elastic compression wrap for reducing swelling and time to return to activity. An elastic bandage combined with a plaster removable posterior splint can also be used. A study of compression stockings in patients with ankle sprain showed that they did not significantly modify the time to return to normal painless walking.22

Figure10

Fig 10 Ankle brace commonly used in the initial treatment of ankle sprain

Evidence supports three to seven days of cryotherapy. Most studies have used a protocol of 20 minutes every two hours. Crushed ice in a plastic bag may be applied over a thin layer of cloth, taking care not to cause frostbite injury. Alternatively, the ankle may be cooled by immersion in water at a temperature of about 12.8ºC.2 3

The injured extremity should be raised 15-25 cm above the level of the heart to facilitate venous and lymphatic drainage until the swelling begins to resolve.

Various non-steroidal anti-inflammatory drugs (NSAIDs) are safe, and topical NSAIDs can provide effective pain control with fewer systemic adverse effects than oral ones. Oral NSAIDs are more effective than placebo at improving pain and swelling in the short term. Comparisons of various NSAIDs have not shown any one agent to be superior to another. No randomised controlled trials have compared oral NSAIDs with topical ones. Paracetamol and mild opioids are also effective.23

Walking aids (usually crutches) are useful in patients who have difficulty bearing weight. As soon as the pain allows, patients should start weight bearing and range of motion rehabilitation.2 21 Range of motion must be regained first, before functional rehabilitation begins. Regardless of weight bearing capacity, Achilles tendon stretching should be instituted.9

Once range of motion is regained, the patient begins the strengthening phase, starting with isometric exercises performed against an immovable object. The patient then progresses to dynamic resistive exercises using weights or resistance bands. These combine eccentric (muscle lengthening or stretching) and concentric (muscle contraction or shortening) exercises.2 3 It is important to strengthen the peroneal muscles, because insufficient strength in this muscle group has been associated with ankle instability and recurrent injury.

The next phase involves proprioceptive training for the recovery of balance and postural control. Various devices have been specifically designed for this phase of rehabilitation (for example, wobble boards).24 25

Finally, the patient progresses to jogging, running, and return to sport. Use of a brace or tape may be recommended during the early period of activity specific training.

The average time to return to sport or full weight bearing status (defined at 20 pain-free hops on the effected ankle) is six weeks for a simple sprain (grade 1), 6-12 weeks for a grade 2 sprain, and up to three months for a grade 3 sprain. The goal of treatment is to prevent chronic instability of the ankle. Ankle injuries with some degree of instability have a 35% chance of at least one re-sprain within the first three years.26

The main predictive factor for chronic instability is the severity of the initial injury.27

Evidence does not support immediate surgical repair of lateral ankle sprains. Surgery is best reserved for patients with chronic ankle instability who do not respond to rehabilitation.28 Operative reconstruction or repair can be performed many years after the initial injury, and the results are as good as after primary repair. However, early surgery is needed for injury to the syndesmosis, which highlights the importance of accurate examination and investigations.

Systematic reviews have found no benefit with the use of therapeutic ultrasound,29 acupuncture,30 or hyperbaric oxygen therapy.31

6. What features warrant specialist referral in patients with ankle sprain presenting to general practice?

Short answer

Concerns about fracture, osteochondral injury, neurovascular compromise,32 tendon rupture or subluxation, or syndesmosis injury in acute presentations. Persistent instability, recurrent instability, and persistent pain after completion of rehabilitation.

Discussion

General practitioners should take a focused history, examine the patient, and follow the Ottawa guidance for imaging (see question 2) in all patients presenting with acute injury.

Immediate specialist referral is warranted if there are concerns about any of the following:

  • Fracture: according to Ottawa guidance

  • Displaced osteochondral injury: history of locking or sensation of something trapped in joint

  • Associated nerve palsy: usually common peroneal nerve

  • Tendon rupture: usually peroneal

  • Injury to the syndesmosis: positive squeeze and external rotation test; tenderness of the proximal fibula.

Otherwise the patient can be managed as indicated in the answer to question 3 and reviewed in 8-12 weeks. At review ask about any feelings of the ankle giving way, which often occur on uneven surfaces or when going up or down steps.

Indications for referral for specialist opinion include persistent instability, recurrent instability, and persistent pain.

Persistent instability may indicate incomplete healing of the ligaments or incomplete rehabilitation. If the lateral ligaments do not regain their function, the talus can tilt into varus within the ankle mortice. A 1 mm shift of the talus in the mortice causes a 42% reduction in the area of contact between the tibia and the talus.33 Stress per unit area increases as the total contact area decreases, which can cause premature joint wear.

Recurrent instability can indicate a continued loss of proprioception. Mechanoreceptors are present in the ligaments and capsule of the ankle. Disruption of the ligament therefore impairs the reflex stabilisation of the ankle. Recurrent instability may also indicate that the ligaments have healed in a lengthened position, or that there is persistent peroneal muscle weakness after injury.

Recurrent instability may also indicate a pre-existing condition that predisposes to recurrent ankle sprain. A cavus foot deformity is characterised by an elevated longitudinal arch and a varus hindfoot. This predisposes patients to recurrent ankle sprain, and the deformity may need to be corrected to prevent recurrence.34

Persistent pain after ankle sprain may indicate a missed osteochondral defect or the development of soft tissue impingement. Patients with a missed osteochondral defect may have deep seated ankle pain, mechanical locking, and still have an ankle effusion on examination.7 Patients may also develop scar tissue around the lateral ligaments that can be intermittently trapped in the lateral joint and become inflamed. This anterolateral impingement classically causes laterally based ankle pain on forced dorsiflexion of the ankle.35 36 Such patients should be referred for MRI and specialist opinion. MRI is the most sensitive diagnostic test for osteochondral defects and ligament injuries.18 37 38

Common surgical procedures that orthopaedic surgeons perform in this setting include a Broström lateral ligament reconstruction39 40 or ankle arthroscopy for a talar osteochondral defect or anterolateral impingement.35

7. How should she be followed up?

Short answer

Evaluation at two weeks and then three months.

Long answer

It is prudent to review patients who present to the GP with ankle sprain but do not require immediate specialist referral (as above) at two weeks and then three months.

The two week review should assess the response to the early phase of treatment to ensure that swelling and tenderness have improved, that the patient can bear weight, and that arrangements for rehabilitation are in place.

The three month review is to ensure that rehabilitation has gone well and the patient has regained function. The average time to return to sport or full weight bearing status (defined as 20 pain-free hops on the effected ankle) is six weeks for a simple sprain (grade 1), 6-12 weeks for a grade 2 sprain, and up to 3 months for a grade 3 sprain. The goal of treatment of acute ankle sprains is to prevent chronic instability of the ankle.

Patient outcome

The patient was given an aircast brace and crutches. She was advised to elevate the leg and apply crushed ice for 20 minutes every two hours for three days. She was also advised to bear weight as tolerated and to remove the brace to do gentle Achilles tendon stretches.

She was seen in the fracture clinic at two weeks and was walking comfortably out of the brace, without crutches. She was referred to physiotherapy to start strengthening exercises, then proprioceptive exercises, and then activity specific exercises.

At three month review she was playing hockey again but was wearing a soft ankle support. She still had occasional feelings of apprehension.

Notes

Cite this as: BMJ 2015;351:h6698

Footnotes

  • Competing interests: We have read and understood BMJ policy on declaration of interests and declare the following interests: none.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

  • Patient consent obtained.

References

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