Rockwood Adults CH64

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SECTION FOUR • Lower Extremity

extend to involve the medial malleolus, and are usually multi- fragmentary (20%), while type 3 fractures consist of only a small shell of posterior malleolus. The classification system is (perhaps inevitably) imprecise: type 1 and type 3 fractures represent two parts of a single spectrum, 233 and applicability of the classification to decision making and prognosis has yet to be demonstrated. However, it is interesting to note that the authors of this paper describe that they only fix the posterior malleolus if fixation of the medial and lateral malleoli first has not restored stability. Evidence of the efficacy (or otherwise) of surgical reduction and fixation is limited to small case series, and there is no consen- sus that fixation can improve outcomes, and if so, which fractures might benefit. Indeed no systematic review has confirmed any benefit from surgery, except for surgery to address talar sublux- ation. 280,395,397 In general, most series describe the nonoperative treatment of smaller fragments and a tendency to surgery for larger fragments. McDaniel and Wilson found that better clini- cal and radiographic results were achieved when patients with fractures involving over 25% of the joint surface were managed operatively in their small series of 15 cases. 242 However, they were unable to achieve adequate reduction or stability in the compar- ator cases which were managed entirely nonoperatively, resulting in residual posterior subluxation in half of these. When Harper et al. retrospectively reviewed 38 patients with posterior malleolar fractures also involving over 25% of the joint surface, they found that the outcomes (including reduction, union, complications and late OA) for operative and nonoperative management were the same. 143 De Vries et al. compared their results for surgically and nonsurgically treated posterior malleolar fractures after 9 to 30 years and found no differences in pain, function, or arthritis. 86 Langenhuijsen et al. also found that neither size nor fixation of the posterior malleolus influenced outcome in 57 patients. 207 Xu et al. recently compared outcomes among patients with frag- ments < 10%, 10% to 25% and > 25% in size, both fixed and not fixed, and found no differences. 422 Furthermore, when Donken et al. reviewed 19 patients 20 years after an isolated posterior mal- leolar fracture treated nonoperatively, they found uniformly good subjective, objective, and radiographic results. 93 The assumption that surgical fixation results in a better reduction than nonsur- gical treatment should also be questioned: In some large recent series the final congruency of fixed fragments was no better 95 or indeed worse 422 than nonoperatively treated fragments. Against this background, case series reporting good results from fixation are hard to evaluate. A series of 52 patients studied at between 1 and 5 years after fixation described ana- tomical reductions (on plain x-ray) in all cases, but a 17% complication rate including infection, sural nerve neurapraxia, loss of reduction, and arthritis requiring, in one case, a total ankle replacement. 399 Similar complications rates of up to 20%, and some new complications, have been reported by others, 61,180,207,256,298,342,397 including amputation. 329 A prospective randomized trial is needed properly to determine the efficacy of this concept, and the results of such a trial being undertaken by the same group 398 are awaited. A subsequent large-scale prag- matic trial may then be needed to confirm whether any advan- tages in expert hands translate to wider practice. An alternative role for posterior malleolus fixation has been suggested related to syndesmotic stability and the origin of the

PITFL which is usually intact after posterior malleolar fracture: where the posterior malleolus can be reduced and stabilized, it will thereby stabilize the syndesmosis. Gardner et al. 121 demon- strated that a PER 4 fracture was more stable after posterior malleolar fixation than after placement of a syndesmosis screw in a cadaveric model, and others 216,255 have subsequently con- firmed clinically that posterior malleolar fixation reliably sta- bilizes the syndesmosis in a variety of fracture types. Whether this represents an advantage over (the less invasive) standard syndesmotic stabilization has yet to be determined. If desired, surgical stabilization is performed either via per- cutaneous reduction and fixation using AP screws from the front, or posterior buttress plating (or posterior-to-anterior lag- ging) via a posterolateral or posteromedial approach. AP screws have the advantage of being percutaneous, which is of benefit in patients with vulnerable skin or those that cannot be placed prone. In contrast, posterior plate fixation in the prone position is aided by gravity, allows access to an impacted fragment, and may allow both more accurate reduction and more secure fix- ation, as first reported by Huber in 1996, 225 a finding that has been confirmed subsequently by others. 33,216,278,342 These advan- tages may, in selected cases, outweigh the limitations of prone plating including prolonged surgical time, higher rate of wound infection, and sural nerve and peroneal tendon injury. Syndesmotic Injuries The syndesmosis is ruptured in ankle fractures (Fig. 64-20) as a result of a torsional movement of the talus that forces the tibia and fibula apart or as a result of a severe abduction force (see Fig. 64-11). However, the ligaments are rarely visualized or subject to MRI scanning, and their integrity is surmised from radiographic diastasis of the syndesmosis. Diastasis requires the rupture of three strong ligaments and the interosseous membrane (see Fig. 64-3) and therefore represents a very substantial insult to the ankle. Not surprisingly, this injury often results in a poor long-term outcome, with or without surgical treatment. 102,183 The interosseous membrane is known to be important in weight transmission through the fibula. 348 Syndesmotic diastasis left untreated may result in persisting instability, pain, and pro- gressive osteoarthritis. 60,212,409 Pettronne et al., 301 in a carefully conducted study of ankle fracture outcomes, demonstrated a poorer overall outcome at 5 years in patients with radiographic evidence of syndesmosis widening, and it is widely accepted that diastasis must be identified at the outset and treated with surgical stabilization. Patients at particular risk of persistent syndesmotic instability include those with a PER fracture with a deltoid ligament rupture (i.e., the high AO type C fracture or Maisonneuve fracture). However, Boden, 40 in his classical cadaveric study, demonstrated that where the medial-sided injury is a malleolar fracture, fracture fixation results in the syndesmosis becoming stable, a finding confirmed by further cadaveric studies. 53,319 Clinical studies treating patients according to this protocol have found good long-term results without syndesmotic fixation in these circumstances. 60,424 It should be borne in mind, however, that fixed fractures of the anterior colliculus associated with a ruptured deep deltoid ligament may be an exception to this