The trans-fibula approach to a posterior malleoli fracture

Background

Posterior malleolus fracture fixation is recognised to prevent unnecessary syndesmotic stabilisation.¹ British Orthopaedic Association Standards for Trauma and Orthopaedics (BOAST) guidelines mandate all tri-malleolar fractures require a computed tomography (CT) scan. We describe an intraosseous approach through the fibula, sparing the need to position the patient in the prone or lazy lateral position if contraindicated by comorbidities.

Technique

Preoperative CT images are utilised to confirm whether the injury contains a coronal plane fracture involving the whole posterior plafond where the line exits through the fibula (Figure 1). At the time of surgery, the patient is positioned supine, and a direct fibula approach is undertaken followed by subperiosteal dissection. The usually oblique fibula fracture is distracted using a laminar spreader (Figure 2a) and the posterior malleolus fracture is approached through the fibula. Reduction is undertaken with direct vision of the articular surface and distal tibial metaphysis, to reduce the cortical read and position the foot in a neutral position to allow for ligamentotaxis. A large Weber clamp can be placed to hold the fracture and Kirschner wire stabilisation is utilised, followed by percutaneous screw fixation in a posterior-anterior configuration. The fibula is then fixed using standard techniques with any associated medial malleolus fracture (Figure 2b and c).

Figure 1 .

Computed tomography scan showing a Liverpool type 3 fracture,² where axial loads led to a fracture configuration in which the fibula is fractured in the same plane.

Figure 2 .

(a) Clinical pictures showing a laminar spreader being utilised to expose posterior malleolus, and the posterior cortical reef is subperiosteally dissected and revealed. (b) Dis-impacting apex of posterior malleolus fracture undertaken with an osteotome. (c) Application of Kirschner wires (K-wire), followed by screw fixation – preferred technique is posterior-anterior screw fixation if feasible; in this case anterior-posterior was used for anaesthetic issues. This was undertaken by an experienced foot and ankle surgeon, judiciously under direct vision to ensure that the posterior malleolus fracture fragment is not pushed away from, rather than being lagged to the tibia. To aid screw placement a K-wire is placed from the anterior tibial surface and measured. Thereafter, it can be directed posteriorly and pushed through, so that the screw can be drilled and placed from the posterior surface. (d) Final fixation and following testing showing reduction and stabilisation of the fracture.

Discussion

The described technique allows fixation of a certain group of posterior malleolar fractures. This allows conventional wisdom to be followed in patients in whom prone/lateral positioning is contradicted by comorbidities, axial trauma or habitus, while still conferring conventional access to the medial ankle for medial malleolus fixation.