Characterizing Fracture-Dislocations And Posterolateral Corner Disruptions In Multiligament Knee Injuries

Multiligament knee injuries are rare and devastating with many possible associated injuries. We focused on two particular associations in this study. For fracture-dislocations, we conducted an extensive literature review to better understand and explore this rare injury with the intention of combining the data from our literature review with our own experience and knowledge of knee fracture-dislocations gained from treating these patients at our Level 1 trauma center to establish our current protocol and recommendations for the treatment of these injuries. For the posterolateral corner disruptions, the purpose was to characterize the ligamentous and myotendinous injury patterns and zones of injury that occur in acute posterolateral corner (PLC) injuries and determine associated rates of dislocations, fractures, peroneal nerve palsies, and vascular injuries. We retrospectively identified all patients treated for an acute multiligament knee injury (MLKI) at our Level 1 trauma center, from 2001 to 2018. From this cohort, all patients with PLC injuries were identified. Demographics, involved ligaments and tendons, neurovascular injury, and presence of fracture were compared to the larger multiligament knee cohort. Incidence of injury and location of injury, from proximal, midsubstance, to distal injury were recorded for the lateral collateral ligament (LCL), popliteus tendon (PLT), popliteofibular ligament (PFL) and the biceps femoris tendon. 100 knees in 100 patients were identified as MLKIs. 74/100 (74%) knees were found to have lateral-sided ligament injuries. 23/74 patients (31%) had a peroneal nerve palsy, 10/74 patients (14%) had vascular injury, and 23/74 (31%) had a fracture associated with their injury. Patients with PLC injuries had higher rates of peroneal nerve injury (p = 0.005) compared to acute MLKIs without a PLC injury. Patients with a complete peroneal nerve palsy were less likely to regain function compared to those with a partial peroneal nerve palsy (p \u3c 0.0001). Of the 74 patients, 72/74 (97%) had injury to the LCL. 3 distinct patterns of injury were observed. Fibular avulsion accounted for the majority (65%) of the LCL injuries, followed by a femoral avulsion (20%) and a midsubstance tear (15%). MLKIs with involvement of the PLC are more likely to suffer peroneal nerve injury and patients with complete peroneal nerve palsy at presentation were much less likely to regain function. Location of injury to the LCL was associated with and predictive of peroneal nerve injury with midsubstance tears and fibular avulsion having a higher rate of peroneal nerve injury