Study designRetrospective, case–control.PurposeKnee morphometric risk factors for noncontact anterior cruciate ligament (ACL) injury have been a popular topic with skeletally mature patients. Little research has focused on the skeletally immature, with conflicting conclusions. This study performs a comprehensive analysis of identified parameters thought to predispose to ACL injury in a skeletally immature cohort.MethodsA retrospective review of pediatric patients undergoing knee magnetic resonance imaging (MRI) was performed over a 4-year period. Inclusionary criteria included mid-substance ACL disruption, skeletal immaturity, noncontact injury, without associated ligamentous disruption, and no medical condition associated with ligamentous laxity. MRI studies were analyzed by a pediatric musculoskeletal radiologist, measuring identified bony parameters, and compared with an age-matched control group without ligamentous injury. Data were analyzed using unpaired t-tests and logistic regression.ResultsOne hundred and twenty-eight patients sustained an ACL disruption, 39 met all inclusionary criteria (66 excluded for associated ligamentous disruption, 23 skeletally mature, three traumatic mechanisms, one with Marfan syndrome). When compared to an age-matched control cohort, the notch width index (NWI) was found to be significantly smaller in the ACL-injured group (p = 0.046). Subgroups analysis demonstrated significant differences in morphometric parameters between subjects with isolated ACL injuries and concomitant medial collateral ligament (MCL) strain.ConclusionsThe NWI was significantly smaller in the ACL injury group. Significant differences were noted between isolated ACL injuries and ACL injuries with an MCL strain. This study further highlights the need for incorporating associated injury patterns when investigating the influence of morphometric factors for ACL injury in the skeletally immature.Level of evidenceLevel III.

The kidneys are the most commonly injured genitourinary organ in children following blunt abdominal trauma. Though the retroperitoneal location affords the kidneys some protection from the forces experienced in blunt abdominal trauma, the kidneys are at greater risk of injury when a disease process exposes them from their normal shielded location. In such cases, the injuries may appear to be disproportionate in relation to the severity of the trauma history, confusing the imaging findings. Recognition of both the underlying disease process as well as the manifestations of acute trauma is important; therefore, we present a pictorial essay of traumatized kidneys in children with pre-existing renal abnormalities.

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.

A torn meniscus frequently requires surgical fixation or debridement as definitive treatment. Meniscal tears with associated fragment displacement, such as bucket handle and flap tears, can be difficult to recognize and accurately describe on MRI, and displaced fragments can be challenging to identify at surgery. A displaced meniscal fragment can be obscured by synovium or be in a location not usually evaluated at arthroscopy. We present a pictorial essay of meniscal tears with displaced fragments in patients referred to a pediatric hospital in order to increase recognition and accurate interpretation by the radiologist, who in turn can help assist the surgeon in planning appropriate therapy.