Stability in ankle fractures: Diagnosis and treatment

Abstract

Medial column (deltoid ligament) integrity is of key importance when considering the stability of isolated lateral malleolus ankle fractures.Weight-bearing radiographs are the best method of evaluating stability of isolated distal fibula fractures.Computed tomography (CT) scanning is mandatory for the assessment of complex ankle fractures, especially those involving the posterior malleolus.Most isolated trans-syndesmotic fibular fractures (Weber-B, SER, AO 44-B) are stable and can safely be treated non-operatively.Posterior malleolus fractures, regardless of size, should be considered for surgical fixation to restore stability, reduce the need for syndesmosis fixation, and improve contact pressure distribution. Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170057.

Keywords: ankle fractures; posterior malleolus; stability; treatment.

Fig. 1

The foot is supinated while external rotation (arrow) causes injury to the anterior syndesmosis (1) and a trans-syndesmotic distal fibular fracture (2). This is classified as a SER 2 fracture. Higher-energy injuries can sequentially damage the posterior (3) and medial structures (4), which are classified as SER 3 and SER 4 injuries respectively. Injury to these structures can be either osseous or ligamentous (SER 3 either posterior malleolus or PITFL, and SER 4 either medial malleolus or deltoid).

Fig. 2

The foot is pronated while external rotation (arrow) causes injury to the deltoid ligament (a, 1) or the medial malleolus (b, 1). The rotational forces will then cause syndesmosis disruption (2) and a supra-syndesmotic distal fibula fracture (3). With further force, the posterior malleolus or the posterior ligamentous structures may be injured (4).

Fig. 3

Gravity stress view with widening of medial clear space.

Fig. 4

Weight-bearing radiograph revealing talar shift and widening of the medial clear space.

Fig. 5

Trimalleolar fracture with computed tomography scan revealing details of the fracture pattern (loose intra-articular fragments) and allowing preoperative planning.

Fig. 6

Syndesmosis screw fixation.

Fig. 7

28-year-old male soldier sustained a high-energy injury and was treated with syndesmosis screw fixation, only, at another institution. He came to us for follow-up at 3 weeks post surgery, in a lot of pain. It was felt that fibula length and rotation had not been restored. A CT scan was requested.

Fig. 8

The CT scan revealed intra-articular fragments and slight mal-reduction of the syndemsosis.

Fig. 9

Revision surgery was undertaken. The posterior malleolus and fibula fractures were fixed through a posterolateral approach. Stress examination (middle view) revealed no syndesmosis instabililty, and no syndesmosis screws were needed.

Fig. 10

The patient made an uneventful recovery and resumed ordinary activities, including high-impact physical exercise, at 6 months.