Outcomes for Surgical Treatment of Posterolateral Instability of the Knee
Treatment outcomes for the posterolateral corner (PLC) of the knee are expected to have high levels of variation because they occur with knee injuries of variable severity and heterogenous-associated ligament pathologies. Injuries to the PLC of the knee occur in isolation <2% of the time.1,2 They frequently occur in combination with an injury to the anterior cruciate ligament (ACL) and/or the posterior cruciate ligament with an incidence ranging from 43% to 80%.1,3,4 In the setting of a knee dislocation, injuries to the PLC could also involve the medial collateral ligament or the posteromedial complex. As there are many associated pathologies that can present with PLC injuries, the outcomes can have significant variations depending upon the nature of the injury. Associated injuries that occur with multiligament knee injuries can have a dramatic effect on outcomes. These include vascular or neurological injures, fractures, muscle injuries that may involve compartment syndromes, and the severity of the injury to the soft tissue and skin envelope. The incidence of vascular compromise in knee dislocations has been reported to occur with an incidence of 32% to 50%.5,6 Neurological injuries that compromise the peroneal or tibial nerves also have a high incidence of up to 20% to 30% in the reported literature.6–12 Multiligament knee injuries will have associated fractures with rates of occurrence as high as 60%.10 A motor vehicle accident highenergy PLC injury that occurs as the result of a knee dislocation with an associated vascular injury could result in compartment syndrome and permanent nerve damage, which would have a far poorer prognosis than an athletic injury that occurs as a basketball player goes in for a lay-up without neurovascular injury. As injuries of the PLC occur frequently with associated injuries, the outcomes will vary depending on the associated injury.