Magnetic Resonance Imaging Evaluation of the Anterolateral Ligament in Acute Anterior Cruciate Ligament Injuries in an Adolescent Population.

PURPOSE: To evaluate the frequency of anterolateral ligament (ALL) injuries in acute anterior cruciate ligament (ACL) injuries in adolescent patients using magnetic resonance imaging (MRI) and characterize other potential intra- and extra-articular knee injuries that are associated with ALL injuries.

METHODS

Patients between 14 and 17 years of age with acute ACL injuries (trauma for <3 weeks before examination) were retrospectively evaluated with MRI over 24 months (January 2016-December 2017). Among this population, ALL was classified as not visible, normal, or injured. Injuries were separated into strains (partial injuries), complete injuries, or Segond fractures. Possible abnormalities of the menisci, collateral ligaments, popliteal tendon, posterior cruciate ligament (PCL), iliotibial tract (ITT), and bone injuries were evaluated. Associations were calculated between ALL injuries and injuries of these other knee structures, as well as age and gender.

RESULTS

ALL was visible in 171 of the 184 MRI-evaluated knees (92.9%). ALL was considered normal in 68 (39.8%) and damaged in 103 (60.2%) patients. ALL injuries were considered partial in 56 (54.4%) and total in 44 (42.7%) cases. Only 3 (2.9%) cases were Segond fractures. ALL injuries were associated with ITT (P < .0001), lateral meniscus (P = .04), lateral collateral ligament (P = .01), popliteal tendon (P = .001), and medial collateral ligament (P = .009) injuries, in addition to bone contusions in the lateral compartment of the knee (P < .0001). There was no correlation between ALL injuries and medial meniscus (P = .054) or PCL (P = .16) injuries.

CONCLUSIONS

MRI evaluation showed ALL injuries are present in 60.2% of acute ACL injuries in adolescent patients. These injuries are associated with the medial and lateral collateral ligaments, ITT, lateral meniscus injuries, and bone contusions, but they are not associated with medial meniscus or PCL injuries.

LEVEL OF EVIDENCE: Level IV, case series.