Abstract
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.
Keywords
pediatric - knee anatomy - anterior cruciate ligament - tibial spine avulsion fracture
