Rockwood Adults CH64

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CHAPTER 64 • Ankle Fractures

The patient is placed supine with a bolster under the ipsilateral hip to allow the foot to lie vertically. A tourniquet is applied and, after exsanguination, inflated to 250 mm Hg. A radiolu- cent box or platform holding the injured ankle above the level of the other side is helpful, allowing lateral fluoroscopy without the need to move the limb. This also opens up a greater arc of movement for instruments. A simple radiolucent box in a Mayo stand cover is ideal. The lateral malleolus is addressed first through a longitudi- nal incision placed directly over the fibula and centered on the fracture. Blunt dissection is performed through subcutaneous fat to avoid damage to the superficial peroneal nerve. The frac- ture is identified and periosteum and ligamentous attachments are debrided back from the fracture edges by 1 to 2 mm: Just far enough to visualize the fracture clearly. The fracture itself is distracted gently to allow irrigation and curettage of clot and small bone fragments. Reduction is achieved and held by the application of a serrated “lobster claw” clamp. There are a num- ber of maneuvers that may assist with this reduction. Firstly, a gentle torsional movement with the reduction clamp may be sufficient to walk the two fractured surfaces out to length and into place. If more force is necessary, distraction and inversion of the foot and ankle will assist in regaining fibular length. Finally, if required, a pointed reduction clamp can be applied to the metaphysis of the distal fragment in the AP plane, and used to apply direct longitudinal traction. The next stage is to place a lag screw across the fracture in an orientation as close to orthog- onal as possible. The serrated clamp is not infrequently found to obstruct either the starting point or anticipated exit point of the drill and screw, and may first need to be replaced with a pointed reduction clamp in a slightly different orientation. The lag screw may be placed in either an AP or a posteroanterior direction. A 3.5-mm gliding hole is drilled first, and a 2.5-mm pilot hole is then drilled through a centering device, followed by counter- sinking, measuring, and screw placement. A one-third tubular plate is selected of sufficient length to allow the placement of three screws above and below the fracture. Often a seven-hole plate is needed to avoid conflict with the lag screw. The plate is precontoured and then applied to the bone with three bicortical screws in the proximal diaphysis, and three cancellous screws in the distal metaphysis. These distal screws are unicortical and extend to, but not through, the second (subarticular) cortex. Their pull-out strength can be improved by varying their ori- entation, typically in a triangular construct. Alternatively, the tip of the plate can be bent sharply to allow a long screw to be placed in a retrograde manner (Fig. 64-22). Fibular Intramedullary Nailing Intramedullary fixation offers a minimally invasive approach to the distal fibula with little palpable metalwork (see Figs. 64-10 and 64-11). Initially popular intramedullary implants, such as Rush nails, were smooth devices with no fixation to bone and were predisposed to backing out, therefore not controlling fibular length or preventing talar shift. 106,282,309 Despite this, Pritchett 309 reported functional outcomes that were good or fair in 76% of a cohort of elderly patients with no complications, a better result than those treatedwith plates. Radiographic results were less

satisfactory, however, with only 40% of cases showing good reduction on postoperative radiographs. To reduce the problems with backing out, Ray et al. 316 used a threaded intramedullary screw and reported good results in patients with minimal fracture comminution. A similar tech- nique was described by Lee et al. 210 using a fully threaded, headless, cannulated screw with variable thread pitch, resulting in good radiographic and clinical results in 95.7% and 91.3% of cases, respectively. Comparisons of intramedullary devices with lateral plat- ing techniques have been encouraging. Lee et al. 209 reviewed 47 patients with Gustilo type I or II open ankle fractures; half were treated with an intramedullary Knowles pin and the oth- ers with a conventional lateral plate based on surgeon choice. Both groups had similarly high rates of anatomical reduction of around 96% but there were significantly fewer soft tissue complications in the Knowles pin group. However, the device has a bulky extraosseous tip and a large number of patients in both groups required later removal of metalwork. Similar results were seen when the same comparison was undertaken in a cohort of elderly patients treated in the same manner. 211 Additional work by Brown 47 reported similarly good clinical and radiographic results but again 55% of patients described discomfort over the tip resulting in a 40% rate of removal of metalwork. Subsequent biomechanical studies have found no significant differences between this intramedullary device and conventional lag screw and lateral plate techniques. 25 The Inyo nail is conceptually unique—a tapered tri- flanged stainless steel nail that can be inserted into the distal fibula through either an open or a closed technique and then augmented with an interlocking nail to prevent migration. McLennan and Ungersma 245,246 reported results in two separate cohorts of 75 patients, with a mean age of 40 years. Good radio- graphic results were obtained in 83% of patients with 88% of patients achieving good functional results. In comparison with conventional lateral plating they found patients reported less pain, quicker return to usual activities and decreased metal- work tenderness. There were significantly lower rates of osteo- arthritis and metalwork removal in the patients treated with the Inyo nail than those treated with a plate. There have been no further reports of its use. The IP-XS nail is a device implanted after open reduction and secured with multiple K-wires. Gehr et al. 125 reported the results of 194 ankle fractures treated with this nail finding good or excellent results in 92% at a mean follow-up of 15 months. There were however a number of soft tissue complications and no further studies have been reported. Percutaneously inserted fibula-specific nails offer further potential. Ramasamy 314 reported his experiences with the Biomet fibular nail in a small cohort of eight osteopenic patients over the age of 50 years: Early functional outcomes were promising with 88% achieving excellent subjective scores. However, 25% of patients did have evidence of osteoarthritis on evaluation of radio- graphs after a mean of 26 months, and one mechanical failure occurred. Rajeev et al. 313 also investigated the use of the Biomet fibular nail in 24 elderly, osteoporotic, predominantly female, patients. After a mean follow-up of 7 months they reported a mean Olerud and Molander score of 57 and no postoperative