Combined posterolateral corner and acute anterior cruciate ligament injuries in an adolescent cohort: a magnetic resonance imaging analysis.

PURPOSE: Failure of a reconstructed anterior cruciate ligament (ACL) has significant morbidity in the paediatric and adolescent patient population. Untreated concomitant posterolateral corner (PLC) injury is an identified cause of failed ACL reconstruction; however, the injury pattern has yet to be defined for the paediatric population. METHODS: Magnetic resonance imaging (MRI) studies of the knee performed between 1 January 2009 and 1 January 2013 were retrospectively reviewed. Imaging reports indicating an intra-substance injury of the ACL were reviewed, and all associated injured structures were recorded. Injury patterns were categorised by age, gender, physis status and associated injuries. Logistic regression and chi-square analyses compared ACL disruptions with and without concomitant PLC injuries. RESULTS: One hundred and twenty-eight patients (74 boys and 54 girls, average age 15.27 years) sustained an ACL disruption. Concomitant injury to the PLC was seen in 13.3% of injuries. Associated PLC injuries were significantly associated with lateral meniscus injury and Segond fractures. Lateral meniscus injury was predictive of PLC injury (p = 0.05) upon logistic regression analysis. CONCLUSION: Concomitant PLC injuries were found in 13.3% of all ACL disruptions on MRI analysis. Lateral meniscus injuries associated with an ACL disruption were predictive of concomitant PLC injury. Combined injury of the ACL and lateral meniscus should prompt close scrutiny to PLC structures.

The Effect of Bony Parameters on the Pediatric Knee: Normal versus Anterior Cruciate Ligament Injury versus Tibial Spine Avulsion Fracture.

Purpose Anterior cruciate ligament (ACL) injuries can present as a ligamentous disruption or avulsion fracture of the tibial spine in pediatric patients. Differences in knee morphometric parameters have been investigated between pediatric cohorts with ACL disruptions and tibial spine avulsion fractures. However, no study to date has compared morphometric parameters in patients with tibial spine avulsion fracture against a control population. Methods A retrospective review of pediatric patients undergoing knee magnetic resonance imaging (MRI) studies was performed, identifying 15 patients with tibial spine avulsion fracture between January 1, 2009, and January 1, 2013. Inclusionary criteria consisted of patients who sustained an acute tibial spine avulsion fracture and had MRI examination. The MRI studies were analyzed by a pediatric musculoskeletal radiologist, who measured identified bony parameters, and results were compared with an age-matched control group and a skeletally immature cohort with ligamentous disruption of the ACL. Data were analyzed using unpaired t test and logistic regression. Results Cohorts included 15 patients with a tibial spine avulsion fracture, 39 with an ACL disruption, and 28 in the age-matched control group. The tibial spine group demonstrated no significant differences in bony parameters when compared with the control group, but had significantly wider tibial eminence widths in comparison to the ACL group (2.92 cm [0.4] versus 2.71 cm [0.27]; p = 0.040). Additionally, this finding was predictive of tibial spine avulsion injury when assessed by logistic regression. Conclusions Pediatric patients who sustain a tibial spine avulsion fracture exhibit significantly wider tibial eminences when compared with the cohort with ACL injuries. This indicates a possible biomechanical explanation for differences in ACL injury patterns that should be examined in future, prospective analyses.