Minimally Invasive Surgical Techniques for the Treatment of High-Energy Tibial Pilon Fractures

John P. Ketz

Roy Sanders

INTRODUCTION

High-energy tibial plafond or pilon fractures are complex injuries that involve the articular surface of the distal tibia. These articular fractures can have a wide range of patterns.¹^, ²^, ³^, ⁴^, ⁵^, ⁶ However, there is always an associated soft tissue injury, and it is often the soft tissue envelope that dictates the method and timing of fixation. Historically, acute open reduction internal fixation (ORIF) was used with some success with low-energy injuries, but poor outcomes and increased complications arose when acute fixation was used for higher-energy injuries.¹^, ³^, ⁶^, ⁷^, ⁸^, ⁹^, ¹⁰ External fixation techniques with no or limited internal fixation, were then tried, but these techniques did not improve outcomes and unfortunately were still associated with a high number of complications.¹¹^, ¹²^, ¹³^, ¹⁴^, ¹⁵^, ¹⁶^, ¹⁷^, ¹⁸ In an attempt to decrease complications and improve outcomes, staged treatment protocols were developed.⁴^, ¹⁹ This concept used temporary external fixation to allow soft tissue edema to decrease until definitive ORIF could be performed. This has been the mainstay of treatment for high-energy injuries for the last twenty years. As our expertise with these fractures has improved, current trends have shifted to using multiple approaches that are even more benign to the soft tissues. These utilize direct visualization and fixation of the articular fragments in combination with minimal incisions to reconstruct the metaphyseal-diaphyseal dissociation.

INDICATIONS

There is little role for the nonoperative treatment of displaced or impacted tibial pilon fractures. It is typically reserved for truly nondisplaced fractures or for patients who have severe contraindications to surgical intervention. The goal of the surgery is not only to restore an anatomic reduction to the joint surface but to realign the mechanical alignment of the distal tibia as well. It is well understood that poor articular reductions and residual tibiotalar incongruity are poorly tolerated by patients and lead to early arthrosis of the ankle joint. There are a number of different techniques available for treatment of these injuries ranging from external fixation to open fixation, or a combination of both. The surgical management of pilon fractures depends on fracture pattern, soft tissue quality, and surgeon preference.

PREOPERATIVE ASSESSMENT

Patients are typically seen in the emergency setting and prompt reduction with splinting optimizes soft tissue management. Following splinting, formal radiographs should be obtained of the tibia and fibula as well as the ankle. A computed tomography (CT) scan may be obtained before initial stabilization with external fixation. This is more appropriate for a lower-energy pattern that may be treated acutely using percutaneous techniques. For higher-energy patterns, due to the concern of radiation exposure, CT scans should be obtained after initial external fixation. Because external fixation will realign the lower extremity, a CT thereafter will offer a much improved evaluation of the articular surface. In addition, Tornetta and Gorup²⁰ have shown the importance of CT scans in planning surgical incisions based on the fracture pattern.

OPERATIVE TECHNIQUES

In virtually all fractures, the first consideration is the fibula. The role of the fibula with respect to the ankle is important in that it establishes length as well as rotation. Often with a high-energy pilon fracture, there can be significant tibial metaphyseal comminution and/or a segmental defect. Because tibial length is difficult to judge, anatomic fixation of the fibula offers the best guide for definitive fixation of the tibia. Additionally, once the fibula is fixed, a stable lateral buttress of the ankle exists and this can obviate the need for lateral-based external fixation. There are a number of fixation techniques for fibular fixation including formal open reduction, percutaneous plating, intramedullary screw fixation, and intramedullary wire fixation. The authors recommend that fibular fixation only be performed by the surgeon who definitively treats the fracture. This will ensure that further incisions or treatment strategies are not compromised due to a previous incision from another surgeon.

FIBULAR FIXATION

Percutaneous Plating

The patient is placed supine on the operating table. A small 2-cm incision is placed over the posterolateral malleolus distally. The peroneal fascia is incised and the tendons are retracted posteriorly. A periosteal elevator can then be used to elevate the peroneal tendons from the posterior aspect of the fibula. A one-third tubular plate is of appropriate length is selected and passed percutaneously proximally along the posterolateral aspect of the fibula. By placing the plate beneath the peroneal fascia, the risk of injuring the superficial peroneal nerve is minimized. A separate incision is then made under fluoroscopic guidance at the proximal extent of the plate. A small tissue dissector is used to identify the plate under the peroneal fascia. The plate is stabilized proximally using 3.5-mm cortical screws. With the plate fixated proximally, attention is turned distally where the fracture is reduced using manual techniques. Next, a medial external fixator is placed across the ankle and traction applied through the ankle joint. The distal fibular fragment can be “fine tuned” through the distal based incision with the aid of pointed fracture reduction clamps. If needed, 1.6-mm K-wires can be placed through the distal fibula into the lateral aspect of the talar body or distal tibia temporarily for added fixation. Once the appropriate length and rotation of the distal fibula is confirmed, 3.5-mm cortical or 4.0-mm cancellous screws are placed distally through the plate. The wound is then irrigated and closed in layered fashion (Fig. 26-1).

Intramedullary Fixation

This technique should be reserved for transverse or short-oblique fractures of the fibula that have minimal comminution. A 1 to 2 cm incision is made over the tip of the lateral malleolus. A medial external fixator is placed across the ankle and traction applied for reduction purposes. The distal fracture segment is stabilized with a pointed reduction clamp. Inversion of the hindfoot should be applied to allow better access to the distal fibula. After drilling, an intramedullary fibular nail is passed. The nail should be placed at a minimum of 4 to 6 cm proximal to the most proximal extent of the fracture.

Figure 26-1. Intraoperative fluoroscopic views of percutaneous plating of a distal tibia-fibula fracture. An external fixator was used to restore the length and alignment of the fracture. (A) The tibia was initially percutaneously plated. Using fluoroscopy, the length of the fibular plate is then confirmed. The plate is then placed through a small incision distally and fixed proximally with a separate small incision. Final fixation as shown in (B) mortise and (C) lateral views.

If a long screw is used, an additional K-wire placed distally across the fibula into the lateral aspect of the talar body is recommended to prevent rotation of the distal fragment while placing the screw. This wire must be placed away from the trajectory of the drill bit, either anteriorly or posteriorly. A 2.5-mm drill bit is placed directly on the tip of the lateral malleolus and drilled across the fracture site under fluoroscopic guidance. Countersinking should be used to minimize prominence of the screw head. The path must be tapped to prevent incarceration of the screw during insertion. A 3.5-mm screw is passed across the fracture site. As with nail insertion, the screw should be 4 to 6 cm proximal to the most proximal extent of the fracture (Fig. 26-2).

Technical tip: If difficulty is encountered passing the drill bit across the fracture site, a 1.6-mm K-wire can be placed in the medullary canal and overdrilled using a cannulated drill bit, slightly past the fracture site. The cannulated tap and counter sink can then be used to create the path for the screw. A cannulated or solid 4.0-mm cortical screw can then be inserted.

When there are associated fractures of the fibula and tibia, newer techniques for limited internal fixation can be applied. Dunbar et al.²¹ advocated limited fixation of proximal tibial fracture segments using anterior, medial, and lateral based incisions. By stabilizing the tibial fracture fragment this converted the fracture from a complete articular pattern to a partial articular fracture. Thus, it simplifies the fracture pattern and allows for less-invasive definitive surgical techniques. The authors have extended
this technique to include fixation of the displaced posterior malleolar fracture fragment initially with fixation of the fibula, if appropriate, through a posterolateral approach. This has been the authors’ preferred treatment method for high-energy injuries involving a displaced posterior malleolar fragment.²²

Figure 26-2. Percutaneous fixation of a distal fibula fracture. (A) A 1.6-mm K-wire is placed, through a small incision distally, into the fibular intramedullary canal. (B) The K-wire is then over-drilled and (C) a cannulated screw is placed across the fracture. (D) Alternatively, this can be performed with a solid screw using lag technique.

Open Reduction and Fixation

The patient is bought into the operating room and placed in the prone position. A tourniquet is placed high on the extremity. The lower limb is then prepped and draped in sterile fashion. The authors routinely exsanguinate the limb with an Esmarch bandage, before inflating the tourniquet. A posterolateral incision is then made midway between the posterior border of the fibula and lateral aspect of the Achilles tendon. The length of the incision is dictated by the proximal extent of the posterior tibial fracture fragment as seen on a fluoroscopic image. Sharp dissection is carried down through skin and subcutaneous tissues. Care is taken to protect the sural nerve. Dissection is carried down to the peroneal fascia. If the fibula is fractured, the fascia is split and the tendons are retracted medially to expose the posterolateral aspect of the fibula (Fig. 26-3). The fibula is then reduced with reduction clamps. If appropriate, a lag screw is placed through the fibula and a neutralization plate applied. Often, there is significant comminution of the fibula and bridge plating is required. Care should be taken in plating the fibula to restore the proper anatomic length, alignment, and rotation. Again, this can best be performed under fluoroscopic guidance.

Operative Technique—Stage 1

Through the posterolateral incision another fascial plane is created medial to the peroneal tendons. The flexor hallucis longus and associated soft tissue are retracted medially, exposing the entire distal and posterior aspect of the tibia. The posterior malleolar fragment typically has a metadiaphyseal spike that can be reduced to the posterior aspect of the tibial shaft, but many times this “key” is fractured and care must be taken to reposition the malleolar fragment anatomically. This reduction is critical to the success of the procedure, as subsequent anterior reconstruction will be based on the proper position of the posterior malleolus. Anatomic reduction of the posterior malleolar fragment also aids in the restoration of the integrity of the ankle syndesmosis (Fig. 26-3). A small or mini fragment plate is then applied spanning the fracture in a buttress or antiglide mode, and secured proximally with cortical screws. If screws are required distally for stability of the posterior malleolar fragment(s), unicortical screws (10 to 14 mm) should be used to prevent interference with the subsequent reduction of the anterior fragments. For this reason, small fragment locking plates are ideal (Fig. 26-4). Reduction and fixation of the posterior components creates a stable buttress for the anterior fragments to be reduced to at the time of final fixation. In essence, a complete articular fracture (OTA 43C) is converted into a partial articular fracture (OTA 43B). Following stabilization of the posterior aspect of the tibia, final images are obtained to evaluate for proper length of the posterior aspect of the tibia and fibula. At this point the wound is thoroughly irrigated and layered closure is performed. The skin is closed with interrupted 3-0 nylon sutures.

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