Incidence and MRI characterization of the spectrum of posterolateral corner injuries occurring in association with ACL rupture

Objective To determine the incidence and MRI characteristics of the spectrum of posterolateral corner (PLC) injuries occurring in association with anterior cruciate ligament (ACL) rupture. Materials and methods We carried out a level IV, retrospective case series study. All patients clinically diagnosed with an ACL rupture between July 2015 and June 2016 who underwent MRI of the knee were included in the study. In addition to standard MRI knee reporting, emphasis was placed on identifying injury to the PLC and a description of involvement of these structures by two musculoskeletal radiologists. Association with PLC involvement was sought with concomitant injuries using correlation analysis and logistic regression. Results One hundred sixty-two patients with MRI following ACL rupture were evaluated. Thirty-two patients (19.7%) had an injury to at least one structure of the PLC, including the inferior popliteomeniscal fascicle ( n = 28), arcuate ligament ( n = 20), popliteus tendon ( n = 20), superior popliteomeniscal fascicle ( n = 18), lateral collateral ligament ( n = 8), popliteofibular ligament ( n = 7), biceps tendon ( n = 4), iliotibial band ( n = 3), and fabellofibular ligament ( n = 1). Seventy-five percent of all patients with combined ACL and PLC injuries had bone contusions involving the lateral compartment of the knee. The presence of these contusions strongly correlated with superior popliteomeniscal fascicle lesions ( p