Joint reduction is accomplished in a timely fashion, typically after radiographs have been performed and assessed. Reduction is best performed with the patient under general anesthesia or deep conscious sedation. Suitable anesthesia facilitates relaxation while decreasing the incidence of iatrogenic chondral damage during reduction attempts. Reduction is performed with the knee flexed to 90 degrees to negate the effect of the gas-trocnemius. The joint is reduced in steplike fashion. First, one accentuates the deformity. Next, joint distraction is accomplished with application of longitudinal traction. Finally, a reduction maneuver is performed in a direction opposite to that of the injury-producing force.4,5
Irreducible dislocations do occasionally occur, as reduction may be blocked by soft-tissue or bony impediments. Irreducible injuries are most commonly associated with lateral peritalar dislocations. Such instances necessitate an open procedure. This permits excision or reduction of the impediments to reduction. In the instance of a lateral dislocation, the posterior tibial tendon is the most commonly encountered impediment. It may become incarcerated into the joint, blocking reduction. In contrast, with medial peritalar dislocations, the talar head may become buttonholed through the extensor digitorum brevis or the peroneal tendons.5
Typically, once the talonavicular joint has been congruently reduced, the foot is stable. Recurrent dislocations are rare; however, on occasion, insertion of a Kirschner wire is necessary due to a persistent unstable foot.3
Figure 70-2 A lateral radiograph demonstrating a peritalar dislocation. The talonavicular joint is disrupted and the subtalar joint is subluxated.
As previously noted, medial peritalar dislocations are decidedly more common than lateral.3,4,6,7 The rate of open injury is variable; Merchan,3 in a series of 39 injuries, documented a 41% rate of open injuries. Compound injuries obviously represent orthopedic emergencies and are managed with urgent irrigation and débridement, reduction, and appropriate antibiotic coverage to prevent deep infection.
Peritalar injuries are commonly associated with osteochondral fractures involving the head and/or body of the talus as well as associated foot and ankle fractures, especially metatarsal and malleolar fractures. Multiple authors have highlighted an incidence of associated fractures in the range of 40% or more.3,4,6 These concomitant injuries may adversely affect rehabilitation efforts. A computed tomography study of the hindfoot is recommended to rule out occult injuries not evident by conventional radiography.5,6
Overall, the prognosis following a peritalar dislocation is guarded. In their series of 17 patients, DeLee and Curtis4 found only five patients with range of motion comparable to that of the contralateral, noninjured extremity. Specifically, the average arc of subtalar motion following a medial dislocation was 24 degrees, whereas with lateral dislocations a subtalar arc of 17 degrees was present.4 Similarly, in a report of 18 peritalar dislocations, Garofalo et al7 reported excellent results in only 56% at an average follow-up of 10 years. Subtalar arthrofibrosis and/or post-traumatic arthritis are thought to be primary deterrents to satisfactory outcomes. A subtalar fusion or triple arthrodesis may be considered as a salvage procedure for persistent subtalar dysfunction.
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