Surgical Treatment of Ankle Fractures

Eben A. Carroll, MD

Alejandro Marquez-Lara, MD

Suman Medda, MD

Jason J. Halvorson, MD

Dr. Carroll or an immediate family member has received royalties from Globus Medical; is a member of a speakers’ bureau or has made paid presentations on behalf of Smith & Nephew and Synthes; serves as a paid consultant to or is an employee of Smith & Nephew and Synthes; has received research or institutional support from Smith & Nephew and Synthes; and has received nonincome support (such as equipment or services), commercially derived honoraria, or other non-research-related funding (such as paid travel) from Smith & Nephew and Synthes. None of the following authors or any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter: Dr. Marquez-Lara, Dr. Medda, and Dr. Halvorson.

PATIENT SELECTION

The ankle is the most frequently injured weight-bearing joint in the body, making ankle injuries commonplace to most orthopaedic surgeons.¹ Injury is usually the result of indirect rotational forces but also less commonly occurs after a direct blow. These forces result not only in bony fracture but also variable degrees of ligamentous and soft-tissue injury. Because ankle stability depends on both bony and ligamentous integrity, injury to both types of structures must be recognized and treated appropriately.

Fractures may be classified based on the anatomic site of injury or the mechanism of injury. The most common of the latter type is the Lauge-Hansen² classification system. This system predicts the position of the foot and the direction of the primary deforming force based on the displacement pattern, level, and morphology of the fibula fracture. The most common anatomic classification system is the Danis-Weber³ system. This system uses the level of the lateral malleolar fracture in relation to the articular surface to classify these injuries.

As is true of many classification systems, neither of these systems perfectly predicts the need for surgical intervention. Each injury needs to be individualized and treatment decisions based on bone and ligamentous stability or lack thereof. Common to many of these injuries is some degree of dislocation or subluxation of the talus within the ankle mortise. It has long been established that even minimal mortise malalignment results in altered contact pressures and the risk of subsequent arthritis.⁴ Imperative to successful management of these injuries is a stable, anatomically reduced ankle mortise. Stability is imparted by restoring the integrity of the bony injury and associated ligamentous injury.

Critical to decision making is the condition of the soft tissues. Marked swelling, the presence of fracture blisters, or other skin changes should delay surgery until the soft-tissue milieu resolves. Many ankle fractures can wait up to 3 weeks before undergoing definitive management without the need for significant change to surgical technique or any deleterious effect on outcome.⁵ These considerations are of particular importance in the elderly and in those with diabetes.

All patients with suspected ankle injuries should get AP, mortise, and lateral radiographs. There are three important radiographic measurements with which all surgeons treating ankle fractures should be familiar: medial clear space (MCS), tibiofibular overlap (TFO), and tibiofibular clear space (TFCS) (Figure 1). In general, lateral shift of the talus 2 mm or greater (as measured by the MCS) or fracture displacement greater than 2 mm has been an indication for surgical intervention. The importance of dynamic stress views has recently been highlighted.⁶ These views may demonstrate dynamic talar shift that may go unappreciated on static nonstress views (Figure 2). Similarly, injury to the syndesmosis may be obvious with widening of the distal tibiofibular joint or appreciated only on dynamic stress examination.⁷ TFCS >6 mm on either the mortise or AP radiograph, or TFO <6 mm on the AP and <1 mm on the mortise view is suggestive of a syndesmotic injury.

Monomalleolar fractures most commonly involve either the medial or lateral malleolus. Although long-term studies are lacking, most nondisplaced or minimally displaced (less than 2 mm) medial or lateral malleolar fractures are treated nonsurgically.⁵ Monomalleolar injuries displaced more than 2 mm should undergo surgical intervention.¹ There is little role for nonsurgical management of bimalleolar and trimalleolar ankle fractures, fracture-dislocations, syndesmotic injuries, and open fractures; all of these injuries require surgical management in the absence of absolute contraindications to surgery.¹ Historic indications for the fixation of posterior malleolar fragments include those fractures that comprise greater than 25% of the tibial plafond and remain displaced greater than 2 mm after fibular fixation.¹ Recent literature, however, suggests that these indications may be expanding
and that posterior malleolar fixation may improve fibular reduction and help restore the integrity of the syndesmosis by restoring the ligamentous connection between the fibula and the tibia via intact posteroinferior tibiofibular ligaments.⁸^,⁹ Failing to address syndesmotic instability can significantly compromise a patient’s outcome; however, studies have demonstrated that current techniques fail to achieve anatomic reduction of the syndesmosis in 25.5 to 52% of patients.¹⁰^,¹¹ If disrupted, the deltoid ligament contributes to the instability of the syndesmosis and may warrant repair or reconstruction.¹²

FIGURE 1 Illustration depicts the parameters commonly measured when assessing ankle stability. The medial clear space (MCS) should be 4 mm or less on the AP and mortise views. The tibiofibular overlap (TFO) should be 6 mm or more on the AP view and 1 mm or more on the mortise view. The tibiofibular clear space (TFCS) should be 6 mm or less on both AP and mortise views.

FIGURE 2 AP radiographs of isolated right distal fibula fracture. A, The medial clear space (MCS) appears normal on a static view. B, Note the increased MCS, suggestive of widening with gravity stress.

PREOPERATIVE IMAGING

The case described here is a 76-year-old man who sustained an ankle injury as a result of a motorcycle accident. He presented to the emergency department with a closed trimalleolar ankle fracture-dislocation (Figure 3, A and B). He underwent closed reduction under conscious sedation in the emergency department (Figure 3, C through E). He was subsequently discharged from the hospital and was brought back for formal surgical management 4 days after the injury when outpatient examination revealed resolution of swelling and a soft-tissue milieu appropriate for surgical intervention.

VIDEO 79.1 Trimalleolar Ankle Fracture Fixation. Eben Carroll, MD; Jason Halvorson, MD (14 min)

View Quicktime Video

Video 79.1

PROCEDURE

Room Setup/Patient Positioning

The room setup is depicted in Figure 4. The operating surgeon and the instrument table are on the same side as the ankle injury. Intraoperative C-arm imaging, which is required, is set up on the side opposite the surgical
extremity. This setup allows the surgeon to work and gain concomitant imaging with little obstruction or frustration.

FIGURE 3 AP (A) and lateral (B) radiographic views show a trimalleolar ankle fracture-dislocation in a 76-year-old man. AP (C) and lateral (D) postreduction radiographs and sagittal reconstruction (E) of the posterior malleolar component. Note the now-reduced ankle mortise (C) and restoration of the tibiotalar relationship in the lateral plane (D). E, The size and displacement of the posterior malleolar fracture fragment are evident.

The position of the patient depends on the nature of the ankle injury. For most isolated monomalleolar fractures and bimalleolar injuries, the patient is positioned supine. A nonsterile bump is often placed under the affected hip, and a nonsterile tourniquet is applied. If there is a trimalleolar injury in which the posterior malleolar fracture needs to be addressed, we prefer the setup shown in Figure 5, A. In the patient depicted in Figure 3, there was a posterior malleolar fragment that needed to be addressed surgically. The patient was placed in a lateral position on a beanbag. This allows for a posterolateral approach to the fibula and posterior malleolus. The patient is then rolled into a supine position for fixation of the medial malleolar fracture (Figure 5, B).

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