Rockwood Adults CH64

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CHAPTER 64 • Ankle Fractures

syndesmosis (Fig. 64-11). Operative treatment of this fibular fracture differs from that of an SER 4 fracture in that lag screw fixation of the comminuted region is often not possible, and an alternative strategy of bridge plating with a small fragment DCP or equivalent, rather than a 1/3 tubular plate, or an intramedul- lary nail may be required. The medial fracture can be addressed with orthogonal cancellous lag screws as for the SER fracture, or with a tension band construct if the fragment is small. The integrity of the syndesmosis should be assessed. Pronation External Rotation Fractures In the first stage (PER 1), an isolated medial malleolar fracture (or deltoid rupture) is produced. In the second stage (PER 2), either the AITFL is ruptured or a tubercle of Chaput fracture occurs. In the third stage (PER 3), a fracture of the fibula occurs through torsion resulting in an oblique or spiral fracture. This differs from the SER fracture in that it is typically suprasyndes- motic (equivalent to an AO type C fracture) and that the long spike at the proximal extent of the fracture is anterior (i.e., the fracture line passes from distal posteriorly to proximal anteri- orly). A PER 3 fracture is unstable and there is a high associ- ated incidence of syndesmosis injury. The classic variant is the so-called Maisonneuve fracture (Fig. 64-12), which may not be diagnosed correctly unless suspected and looked for. Surgical stabilization of the fibular fracture is with a plate if it occurs within 5 or 6 cm of the syndesmosis, with or without a syn- desmosis screw. Fractures above this level are most commonly treated with syndesmosis screw(s) alone. The medial malleolar fracture is commonly treated with cancellous lag screws. Despite the utility of the Lauge–Hansen classification system, later investigators have not been able to replicate the stages of injury described in the original experiments, 137,249 and more recently an innovative study comparing the mechanism of injury

as seen on “YouTube” movie clips and the subsequent x-rays of the same patient failed to find a strong correlation between mechanism and fracture pattern. 205 In common with other classi- fication systems, it does not provide reliable information regard- ing the presence or absence of syndesmotic rupture. 122,274,425 Like most detailed classification systems, reproducibility is modest with interobserver variability of between 43% and 60% and intraobserver variability of between 64% and 82%. 273,377 How- ever, the classification system does have prognostic significance: The degree of articular damage has been shown to correlate with the stage of injury. 215 Eponymous Terms A number of eponymous terms have also survived by custom and common usage. A Volkmann’s fracture refers to a fracture of the posterior malleolus, 400 although the fracture was first described by Earle, the grandson of Sir Percival Pott. 98 A Maison- neuve fracture is a fracture of the proximal fibula associated with a medial malleolar fracture or deltoid ligament injury, account- ing for 5% of all ankle fractures, 293 although Maisonneuve actually described a number of fractures of both the proximal and distal fibula in association with a rotational injury. 228 It is important to exclude this proximal fracture in rotational ankle injuries as it is highly unstable despite potentially normal ankle radiographs. The proximal tibia should be carefully palpated and, where there is tenderness, full-length views of the tibia and fibula should be obtained (Fig. 64-12). CLINICAL ASSESSMENT OF ANKLE FRACTURES Assessment of an ankle fracture requires a detailed history, a thorough physical examination and radiographic imaging. While the patient’s own account of a low-energy twisting injury

A, B

C

Figure 64-11.  A pronation abduction (PAB3) fracture (AO/OTA C2.3). A: The initial radiograph shows a medial malleolar fracture, a comminuted suprasyndesmotic fibular fracture and a diastasis. B: The medial malleolar fracture has been stabilized with two screws and the fibular fracture with a bridging plate. A diastasis screw has been inserted. C: An intramedullary nail can be used for the fibula.