Orthopedic Teaching Cases 2022, Dec, 05 | 12:00 am

Foot and ankle structured oral questions1: Lateral ligament instability of the ankle

Foot and ankle structured oral questions1:

Lateral ligament instability of the ankle

EXAMINER. Tell me what this diagram represents and name the structures labelled 2, 3 and 5. (Figure 4.1.)

CANDIDATE. This diagram is a representation of the lateral aspect of the ankle showing the bony and ligamentous structures. Structure 2 is the anterior talofibular ligament, structure 3 is the calcaneofibular ligament and structure 5 is the posterior distal tibiofibular ligament.

EXAMINER. What structures are injured in a lateral ligament injury?

CANDIDATE. The mechanism is usually a rotational injury with sequential failure of the ligaments from front to back, hence the anterior talofibular ligament or ATFL is most commonly injured followed by the calcaneofibular ligament or CFL and the posterior talofibular ligament is the least frequently injured.

EXAMINER. How would you go about diagnosing a lateral gastrocnemius soleus complex. For the anterior drawer test the distal tibia is grasped in one hand and the other hand grasps the heel and the foot is drawn anteriorly in relation to the talus. Pain or excess anterior translation or a sulcus sign developing at the anterolateral corner of the ankle are signs of an ATFL injury. The other ankle must be examined for comparison. The talar tilt test involves inversion of the ankle whist palpating the anterolateral corner of the joint to feel for movement of the talus within the mortise. A lack of firm end point or tilt in excess of the normal side would represent instability and the CFL is considered to have been injured if this test is positive.

EXAMINER: What other clinical findings may be positive in a patient with recurrent ankle sprains?

CANDIDATE: Ankle sprains are more common in patients with a cavus foot deformity or hypermobility.

EXAMINER: If you suspect a lateral ligament injury how will you proceed in managing this patient?

CANDIDATE: The first step in management would be rehabilitation with physiotherapy, concentrating on peroneal strengthening and proprioceptive training. If the dynamic stabilizers of the ankle are well conditioned the majority of patients recover well from a ligament injury. Bracing may be of benefit.

EXAMINER: ... and if the patient continues to have significant symptoms despite adequate rehabilitation?

CANDIDATE: A patient that fails to recover would need more investigation. I would begin with simple weightbearing radiographs of the ankle. Stress X-rays of the ankle may be diagnostic for diagnosing a ligament injury, however if the patient is still having significant pain and swelling I would request an MRI scan to look for additional pathology.

EXAMINER: What other conditions would you be looking for?

CANDIDATE: My differential diagnosis for an ankle sprain that doesn’t get better, in addition to incomplete recovery or rehabilitation would be peroneal tendon pathology such as a split tear or subluxing tendons, intra-articular pathology such as an osteochondral defect of the talus or loose body, or nonunion of an anterior calcaneal process fracture in addition to the presumed diagnosis of lateral ligament injury.

EXAMINER: What are the surgical options for management of an isolated lateral ankle ligament complex injury in a young patient who has failed to respond to non-operative treatments?

CANDIDATE: The options would be a lateral ligament repair or reconstruction of the lateral ligaments.

EXAMINER: Do you know any methods of surgical repair?

CANDIDATE: Yes, the Broström repair.1

EXAMINER: What are the principles of that operation?

CANDIDATE: It is an anatomical repair of the lateral ligaments. The ATFL and CFL are imbricated to re-tension them. The extensor retinaculum may then be sutured over the top of the repair for additional strength. Consideration should be given to performing an ankle arthroscopy first at the same sitting to diagnose and address any associated intra-articular pathology.

EXAMINER: Are intra-articular lesions common in this group?

CANDIDATE: Various studies have found chondral injures in a significant proportion of chronic ankle instability. In one study associated intra-articular pathology amenable to arthroscopic treatment was identified in 83% of patients undergoing

Brostrom repair.2

EXAMINER: A patient asks how successful a ligament repair will be, what will you tell them?

CANDIDATE : I would expect a successful result in over 80% of patients.

EXAMINER: Tell me about the options available for lateral ligament reconstruction.

CANDIDATE: There are several operations described for lateral ligament reconstructions. The majority of these involve sectioning the anterior half of the peroneus brevis proximally, leaving the distal end attached and routing the free end to reconstruct a lateral ligament. The reconstruction can be anatomical or non-anatomical. I have experience of the modified Chrisman–Snook procedure which transfers the anterior half of the peroneus brevis through bone tunnels in the distal fibula and lateral calcaneum to form an anatomical reconstruction of both the ATFL and CFL. I understand that many surgeons are moving towards reconstruction using a free hamstring graft in athletes to avoid harvesting one of the dynamic ankle stabilizers.3

EXAMINER: Thank you.

  1. Broström L. Sprained ankles VI: Surgical treatment of

‘chronic’ ligament ruptures. Acta Chirurgica Scand 1966;132(5):551–565.

  1. Kibler WB. Arthroscopic findings in ankle ligament reconstruction. Clin Sports Med 1996;15(4):799–804.

  2. Boyer DS, Younger AS. Anatomic reconstruction of the lateral ligament complex of the ankle using a gracilis autograft. Foot Ankle Clin 2006;11(3):585–595.