Magnetic resonance imaging evaluation of anterolateral ligament injuries and associated lesions in acute anterior cruciate ligament tears

OBJECTIVE: The first aim of our study was to investigate the appearance of the injured Anterolateral Ligament (ALL) on magnetic resonance imaging (MRI) performed in acute anterior cruciate ligament (ACL) injuries and provide data about the inter- and intra-rater agreement in assessing the ALL status. The second aim was to describe the incidence of associated injuries in acute ACL-injured knees and provide data regarding the inter- and intra-rater agreement in identifying these. PATIENTS AND METHODS: Patients with ACL lesions who underwent MRI within 10 days from the injury were included. Images were evaluated by an orthopedic surgeon and a musculoskeletal (MSK) radiologist. Inter- and intra-observer reliabilities were determined for MRI parameters of the anterolateral ligament (ALL) and associated injuries by using the kappa (κ) test. RESULTS: A total of 100 patients were evaluated. ALL abnormalities were observed in 93% of the cases. Inter-observer reliability was substantial to almost perfect concerning ALL signal, femoral and tibial bone bruises, femoral notch sign and meniscal tears (κ = 0.6-1); moderate agreement was observed for lateral meniscus tears (κ = 0.56) and Segond fractures (κ = 0.45). Intra-observer reliability of the orthopedic surgeon was substantial to almost perfect for all the criteria evaluated (κ = 0.6-1). Intra-observer reliability of the MSK radiologist was substantial to almost perfect for ALL injuries and bone bruises (κ = 0.6-1); there was a moderate agreement for meniscal tears and Segond fractures (κ = 0.41-0.6), except for Lateral Meniscus Posterior Horn Root Tears (κ = 0.21). CONCLUSIONS: MRI can represent an instrument of high reliability and reproducibility in the diagnosis of ALL tears and associated lesions in patients with acute ACL ruptures.