Calcaneofibular ligament injury

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Calcaneofibular ligament injuries typically occur in conjunction with an anterior talofibular ligament injury within the scope of a lateral ankle sprain and are rarely found isolated. The injuries can comprise either ligament tears, avulsion fractures or both.

Epidemiology

The calcaneofibular ligament is the second most common ligament injured (after the anterior talofibular ligament) in a very high percentage of lateral ankle sprains. Isolated calcaneofibular ligament injury is rare .

Associations

Clinical presentation

Clinical signs and symptoms are that of an acute lateral ankle sprain, but in case of a calcaneofibular injury they will be typically more severe and also depending on the grade of injury will result in talocrural joint instability and talar tilt. Conversely, an unstable ankle joint after sustaining a lateral ankle sprain will more likely coincide with a calcaneofibular ligament injury. The calcaneofibular ligament can additionally be assessed with the inversion stress test in a dorsiflexed position .

Complications

If left untreated calcaneofibular injury can lead to the following conditions:

Pathology

Mechanism

Calcaneofibular ligament injuries typically occur along with an anterior talofibular ligament injury within the scope of a lateral ankle sprain. The typical mechanism is excessive supination of the rearfoot on an externally rotated lower leg, leading to an inversion-internal-rotation type injury . Isolated injury is rare but can occur on supination or inversion on a dorsiflexed ankle where the anterior talofibular ligament is relaxed .

Radiographic features

Plain radiograph

Plain radiographs may show a lateral malleolar tip or avulsion fracture other findings include lateral malleolar soft tissue swelling.

Ultrasound

The calcaneofibular ligament will be hypoechoic and thickened or swollen in case of a sprain. Partial tears might show anechoic defects and undulated or irregular ligament fibers. Complete tears might show anechoic defects, tendon stumps displaced superficial to the usually overlying peroneal tendons.

MRI

The usual appearances of calcaneofibular ligament injury are thickening in case of a sprain or chronic injury, ligament contour irregularities, partial discontinuity, and signal intensity changes in case of partial tear and complete discontinuity and fiber retraction in case of a complete tear .

Similar to other ligament injuries inhomogeneity of the ligament with intraligamentous signal intensity on fat-suppressed T2-weighted or intermediate weighted sequences indicate intrasubstance tearing .

In addition to the ligamentous alterations, there might be bone-marrow like lesion at the distal fibular and calcaneal insertion sites or signs of tenosynovitis of the peroneal tendons.

Radiology report

In case of a calcaneofibular injury the report should look similar to that of a lateral ankle sprain and should include the description of the following:

  • calcaneofibular ligament injury (sprain, partial tear, complete tear)
  • anterior (and/or posterior) talofibular ligament injury (sprain, partial tear, complete tear)
  • concomitant subtalar joint injury
  • avulsion injuries of the lateral malleolus
  • signs of tenosynovitis or injury to the peroneal tendons
  • possible concomitant syndesmotic injury
  • fractures or fracture-dislocations
  • chondral or osteochondral injury

Treatment and prognosis

Calcaneofibular ligament injuries are the result of a more serious form or higher grade lateral ankle sprain and the calcaneofibular ligament provides a significant contribution to lateral ankle stability .

Management is nevertheless most often conservative and includes initial treatment with rest, ice, compression and elevation (RICE) and semi-rigid ankle brace and/or a short-term period of immobilization in more severe cases.

Subsequent therapy includes a comprehensive rehabilitation with emphasizing proprioception, neuromuscular and postural control with motion or movement exercises, strengthening exercises, balance training and endurance and agility exercise .

Surgical treatment is decided on an individual basis and includes ligament repair or reconstruction either arthroscopically or with an open approach. Surgery can reduce recurrence rate, but has similar overall outcomes as conservative management.

Differential diagnosis

Practical points

Calcaneofibular ligament injuries usually go along with anterior talofibular ligament injuries, which should be looked out for on MRI or ultrasound in the assessment of an ankle injury.

In the case of combined anterior talofibular and calcaneofibular ligament injury, the deltoid ligament should also be assessed with respect to possible deltoid ligament injury.

See also