Visualization of Concurrent Anterolateral and Anterior Cruciate Ligament Injury on Magnetic Resonance Imaging

Abstract

To investigate the ability to visualize the anterolateral ligament (ALL) on magnetic resonance imaging (MRI) and identify ALL injuries in an intact- anterior cruciate ligament (ACL) and torn-ACL cohort. We also aimed to assess inter-rater reliability between 2 radiologists when it comes to the aforementioned assessment. MRIs that met inclusion and exclusion criteria were placed into a control (ACL-intact) or study (ACL-injured) cohort. MRIs were independently analyzed by 2 radiologists for data points pertaining to demographics, ALL visualization, presence of ALL injury, and concomitant knee abnormalities. Inter-rater reliabilities for visualizing the ALL and identifying ALL injuries were assessed. The control and study groups consisted of 116 and 82 MRIs, respectively. Age varied between the 2 groups, but sex distribution was similar. With near-perfect agreement (kappa= 0.92), both radiologists visualized at least part of the ALL in more than 95% of MRIs irrespective of ACL integrity. The mean incidence of ALL injury in the ACL injured group was 53.05% with minimal inter-rater agreement (kappa= 0.38). Segond fractures were noted in a mean 13.95% of MRIs with concomitant ALL and ACL injuries. The ALL was reliably visualized on MRI irrespective of whether the ACL was intact or torn. However, ALL injuries were not reliably diagnosed on MRI in the setting of an ACL tear. Poor interobserver reliability shows the potential for false-positive and -negative interpretation. These findings suggest that, in this study, ALL injuries could not be accurately diagnosed in the presence of an ACL tear using MRI. On the basis of these findings, it is recommended that physicians should not rely on MRI to diagnose an ALL injury in the presence of an ACL injury. Level III, retrospective comparative trial.