Rockwood Adults CH64

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CHAPTER 64 • Ankle Fractures

to the deltoid ligament) and this is achieved by first passing a 14-guage intravenous cannula through the deltoid ligament so that it lies tightly in the “axilla” formed between the cortex of the fragment and the K-wires. The wire is then placed into the cannula opening and pushed through the ligament using the cannula as a guide. The K-wires are then cut and bent through 180 degrees and are impacted over the flexible wire. Again, the metalwork should lie against the bone, and a longitudinal inci- sion in the deltoid ligament will help the wire to pass through the ligament to bone.

Treatment of Posterior Malleolar Fractures: INDICATIONS Nonoperative AP Screws

Posterior Screws/Plate

• Fragments

• Posterior talar subluxation after medial and lateral malleolar fixation • Fragments > 25% plafond with talar subluxation • Elderly patients • Younger patients

< 25% plafond

• Undisplaced fragments

• Vulnerable soft tissues

• Marginal impaction

Potential Pitfalls and Preventive Measures

• Syndesmotic injury

Treatment of Medial Malleolar Fractures: POTENTIAL PITFALLS AND PREVENTIONS Pitfall Prevention

For AP screw fixation, surgery is performed under general anesthesia in the supine position with a tourniquet. Preoperative Planning ✔ ✔ Posterior Malleolar Fixation With AP Screws: PREOPERATIVE PLANNING CHECKLIST

• Very small or

• Use K-wires and tension band wiring technique

osteoporotic fragment

• Supination adduction injury. Vertical fracture line

• Correct any plafond impaction

❑ R adiolucent

OR table

and then use antiglide plate or two cancellous screws placed parallel to joint

❑ B ump under ipsilateral buttock ❑ F oot and leg elevated on radiolucent block

Position/ positioning aids

❑ C ontralateral side

Fluoroscopy location

Posterior Malleolar Fixation Reduction of posterior malleolar fractures, as for other intra- articular fractures, must be anatomical, as nonanatomically fixed posterior malleolar fractures have been shown to have a higher rate of osteoarthritis. 168 Fixation options include either a percutaneous reduction with AP screw fixation (Fig. 64-24), or open posterior buttress plate fixation (see Fig. 64-17). Little comparative evidence is available, although biomechanical evi- dence suggests that buttress plating results in less displacement with cyclical loading. Whether this translates into a clinical benefit has yet to be confirmed, provided the talus is reduced and stabilized. 1,41,116,372,387 There is a dilemma inherent in the evidence-based treat- ment of posterior malleolar fractures. The aim is to prevent posterior talar subluxation. As most ankles are stable after fix- ation of the medial and lateral malleoli, and additional poste- rior fixation has no clear advantages in the majority of cases. However, having fixed an ankle with the patient in the supine position, fluoroscopic assessment of the posterior malleo- lar fracture is often impeded by the fibular plate or nail and, moreover, if a posterior plate is then deemed necessary, intra- operative movement of the patient from supine to prone for posterior plating is fraught with delay and hazard. As there is no certain way to identify the rare unstable posterior injury, the surgeon must make a judgment as to which patients are likely to require posterior plating, and position these patients prone from the outset. Such patients, in the authors’ view, will be young and active, have large fragments, marginal impaction, or clear syndesmotic injury. CT scanning is obtained where required to confirm impaction or retained fragments, and for surgical planning.

❑ S mall fragment set or 4-mm cannulated screws

Equipment

❑ 250 mm Hg

Tourniquet

Other

Technique

✔ ✔ Posterior Malleolar Fixation With AP Screws: KEY SURGICAL STEPS ❑ Place the heel on the radiolucent block and dorsiflex the foot to reduce the fragment ❑ If the fragment does not reduce perfectly on fluoroscopy, make a 1-cm incision posteromedially, just medial to the tendo Achilles ❑ Perform blunt dissection down to the fragment ❑ Use a periosteal elevator to free, push, and reduce the fragment, usually distally (see Fig. 64-24) ❑ Maintain pressure or apply a large reduction clamp ❑ Make a 1-cm incision over the anterior aspect of the ankle, just above the plafond, using fluoroscopy to confirm the location. For two screws, the incisions will be 1/3 and 2/3 across the front of the ankle joint ❑ Perform blunt dissection through retinaculum and down to bone ❑ Place a 1.3-mm guidewire into the posterior fragment and measure ❑ Insert partially threaded lag screw, just engaging posterior cortex ❑ Position second screw ❑ Close stab incisions Considering the placement of AP screws, although several authors emphasize that posterior malleolar reduction is made easier by fixing the fibula first, we have found that the lateral