Morphological Risk Factors for Pediatric Anterior Cruciate Ligament Tears and Tibial Spine Fractures

Background: Both tibial spine fractures (TSFs) and anterior cruciate ligament (ACL) tears result in functional loss of knee stability. Nonetheless, it remains unclear why some patients sustain ACL tears, whereas others have TSFs. Purpose: To identify the common morphological risk factors for pediatric ACL tears and TSFs and to determine the morphological differences between them using multiplanar reconstruction of magnetic resonance imaging (MRI). Study Design: Cohort study; Level of evidence, 3. Methods: Age- and sex-matched participants (159 total [53 ACL tears, 53 TSFs, and 53 controls]) aged <18 years who visited a pediatric tertiary-care center for ACL tears, TSFs, or anterior knee pain from March 2009 to April 2023 were included. Each group comprised 41 male and 12 female participants. Data on demographic characteristics and estimated bone age based on the knee MRI atlas were retrospectively collected, and various knee morphological parameters were evaluated using multiplanar reconstruction of MRI. Parameters showing significant differences among the 3 groups were selected as independent variables for multivariable multinomial logistic regression analysis, with the groups as dependent variables. Results: The mean chronological age at the time of MRI was 13.2 ± 2.3 years. Height, weight, body mass index, bone age, articular medial tibial slope, and bony medial tibial slope did not differ among the groups. Articular lateral tibial slope was independently associated with the occurrence of both ACL tears (relative risk ratio [RRR], 1.42 [95% confidence interval (CI), 1.16-1.74]; P = .001) and TSFs (RRR, 1.33 [95% CI, 1.10-1.62]; P = .004). A high notch width index was a protective factor against ACL tears (RRR, 0.86 [95% CI, 0.77-0.96]; P = .006) but not against TSFs (RRR, 1.01 [95% CI, 0.91-1.12]; P = .848). Conclusion: A high articular lateral tibial slope was a common risk factor for ACL tears and TSFs. Patients with ACL tears had a narrower intercondylar notch than those with TSFs and controls.