When obtaining the patient’s history, it is important to address medical comorbidities and social habits that will influence the choice for operative intervention and postoperative management. Diabetic patients should undergo detailed peripheral vascular and neurologic examination. Signs of poor microvascular status and/or a history of smoking may prompt the surgeon toward less invasive fixation of posterior fragments (percutaneous screws) or nonoperative management due to the increased risk for wound complications. Presence of peripheral neuropathy warrants a prolonged period of non-weight bearing to minimize the risk of implant failure.

Standard X-rays of the ankle should always be obtained. The lateral X-ray is most important in determining the presence and nature of a posterior malleolus fracture. Posterior subluxation of the talus, signifying ligamentous instability, can be reliably identified on the lateral X-ray. If ambiguity exists it may be appropriate to obtain a CT scan of the ankle to better delineate the size of fracture fragment and possible articular comminution or impaction.

Historically, the most common indication for fixing the posterior malleolus has been for fragments greater than 25% of the articular surface [1, 2]. However, articular incongruity with greater than 2 mm step-off [3], syndesmotic associated instability [4, 5], and persistent posterior subluxation despite fibular fixation [6] has also been reported as indications for fixation. One study has shown that the syndesmosis is restored to 70% stability with isolated plating of the posterior malleolus versus only 40% stability restored with isolated syndesmotic fixation in the presence of PM fracture [5].

The posterolateral approach to the ankle is the workhorse for internal fixation as this approach allows fixation of the posterior malleolus fragment as well as the fibula through a single incision [6, 7]. The patient is positioned prone on a radiolucent table (Fig. 5.3). An incision is made in the intermuscular plane between flexor hallucis longus and the peroneal tendons (Fig. 5.4). It is important to identify and preserve the sural nerve located in the subdermal fat layer, as this structure enters the surgical field in approximately 80% of cases [8]. It is our preference to always address the posterior malleolus fragment first as this can aid in restoring length to the fractured fibula. The periosteum is then elevated off the posterior tibia. The posterior malleolus is visualized with medial retraction of the FHL. If medial extension is present, it can sometimes be addressed with further medial retraction of the FHL although this pattern may be better addressed using the posteromedial approach. The fracture is mobilized from medial to lateral and proximal to distal to maintain the ligamentous attachment to the fragment [6]. The fracture fragment is booked open and hematoma is irrigated from within the fracture to remove clot and any loose fragments of bone or tissue which may impede reduction. Reduction can be achieved using a variety of techniques although our preference is for gentle pressure using a ballpoint pusher device. A K-wire placed from posterior to anterior can aid in holding the reduction. Once this provisional reduction is obtained, a buttress plate with screw placement at the apex of the fracture is applied to prevent posterosuperior migration of the fragment. Additional 1–2 screws are placed proximal to the fracture after at least one lag screw is placed through the distal aspect of the plate in order to obtain compression across the fracture. The fibula may be addressed by either medial or lateral retraction of the peroneals and fixation achieved using a 1/3 tubular plate (Fig. 5.5). A stress view to assess the syndesmosis is performed at this point. In this case fixation of the posterior malleolus and fibula sufficiently stabilized the syndesmosis and transsyndesmotic fixation was not needed.