Rockwood Adults CH64

2852

SECTION FOUR • Lower Extremity

Sommer 151 reviewed their results in 20 patients with distal fib- ular fractures describing a small 2- to 3-cm wound distally and 3- to 4-cm wound proximally. They experienced no soft tissue complications but there were three cases of nonunion. Inevitably, they describe the technique as highly challenging. A variety of strategies have been described for reinforcing the fixation of ankle fractures, particularly in osteoporotic bone. Bio- mechanical studies have shown that lateral plate fixation can be augmented by passing one or more screws into the tibia 97,292 and this tibio-pro-fibular technique is a particularly attractive option for patients with osteoporotic bone or peripheral neuropathy. Assal et al. described using a traditional lateral plating technique aug- mented by both polymethylmethacrylate cement injection into the proximal fragment screw holes and an intramedullary axial wire. In a cohort of elderly patients allowed early weightbearing they described no failures of fixation. 21 Koval et al. described a similar technique of augmentation of lateral plating but with intramedul- lary Kirschner wires (K-wires). In clinical and biomechanical stud- ies they reported good results with no failures of fixation in the 20 patients treated with this technique and a construct that had twice the resistance to torsional force of traditional constructs. 197 Preoperative Planning ✔ ✔ Open Reduction and Plating of Ankle Fractures: PREOPERATIVE PLANNING CHECKLIST

locking, compression, or third tubular plates, via open or min- imal incisions. However experience with plating has revealed a number of limitations. The thin soft tissues over the distal fibula, and the subcutaneous location of the lateral plate, predispose to wound dehiscence and infection. Rates between 5.5% 333 and 26% 154 have been reported with higher rates in elderly 14 and diabetic patients. 241 The thin soft tissues in this region may also result in late metalwork irritation and the requirement for secondary removal surgery in up to 50% of patients. 14,243 The incision also puts at risk the superficial peroneal and sural nerves, both of which have highly variable anatomy. 163 With a laterally sided plate, the distal metaphyseal screws are necessarily unicortical and cancellous and risk articular surface penetration. Structural failure may be a problem in osteope- nia: Beauchamp et al. 29 reported stable fixation in only 54% of elderly patients with porotic or comminuted bone. To reduce some of these problems Brunner and Weber 49 described dorsal buttress plating (Fig. 64-21B) in 1982. The posterior to anterior screws reduce the chance of intra-articular penetration and allow bicortical purchase, while the dorsal location of the plate gives increased soft tissue coverage and the more posteriorly placed incision reduces the chance of damage to the superficial peroneal nerve. 317 Good clinical and radio- graphic outcomes have been reported, 285,390,417,418 and the con- struct is certainly biomechanically stronger in vitro, 257,331 but comparative clinical studies have failed to show a clear advan- tage over conventional lateral plating. 206 Moreover, peroneal tendon irritation occurs in up to 43% of patients, and in 30% of patients visible tendon lesions are present at the time of plate removal. 285,408 It appears that dorsal buttress plating largely exchanges the wound complications associated with lateral plating for peroneal tendon complications. Certain configurations such as pronation abduction fractures result in regional comminution that prevent lag screw compres- sion, and in this situation the comminuted segment has to be grafted or bridged (see Figs. 64-11 and 64-21C). Graft augmenta- tion was described by Limbird and Aaron 217 in 1987 who treated eight patients with graft and a one-third tubular plate bridging the comminuted region. In all cases anatomical reduction was achieved and there were no cases of infection or osteoarthritis. Extraperiosteal bridge plating allows indirect fracture reduction, secondary bone healing, and theoretically reduces the damage to the periosteal blood supply of comminuted fracture fragments. In a cohort of 31 patients treated with this technique Siegel and Tornetta 345 reported good clinical and radiographic outcomes and no episodes of nonunion. The mortise must be reduced either fluoroscopically or under direct vision, and accurate restoration of length and alignment of the fibula may be challenging. Although locking plates have a superior in vitro load-to- failure in osteoporotic ankles, 429 comparative clinical studies have not confirmed a definite advantage. Schepers et al. 333 reported that the rate of wound complications following locked plating was 17.5% compared to 5.5% after conventional plat- ing: The bulkier size and technical difficulty of locking plates may currently negate their biomechanical advantage. MIPO techniques may reduce damage to a vulnerable soft tissue envelope, 199 a potential advantage in the ankle. Hess and

❑ Radiolucent

OR table

❑ Supine with a bolster under the ipsilateral buttock. ❑ Radiolucent block under injured ankle

Position/ positioning aids Fluoroscopy location

❑ C -arm from contralateral side

❑ S mall fragment plate

Equipment

❑ 250 mm Hg

Tourniquet

Other

Technique

✔ ✔ Open Reduction and Plating of Ankle Fractures: KEY SURGICAL STEPS ❑ Longitudinal 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 ❑ Periosteum and ligamentous attachments are debrided back from the fracture edges by 1 to 2 mm ❑ Irrigation and curettage of clot and small bone fragments from fracture site ❑ Application of a serrated “lobster claw” clamp, with rotation of clamp or traction on distal fragment to effect reduction ❑ Replace with a pointed reduction clamp ❑ Drill 3.5-mm gliding hole first, then a 2.5-mm pilot hole, measure and countersink, insert screw ❑ 1/3 tubular plate with three bicortical screws in the proximal diaphysis, and three cancellous screws in the distal metaphysis ❑ Wound closure