Bone Bruises in Children and Adolescents Not Associated With Ligament Ruptures [corrected]

Clinical characteristics of uncomplicated bone bruises (ie, not associated with a ligament rupture, meniscal tear, or fracture of the knee) in young athletes have scarcely been reported.

To identify mechanisms of injury, characterize bone bruise patterns, and identify clinical factors relating to recovery in young patients suffering uncomplicated bone bruises about the knee.

Case series; Level of evidence, 4.

A review of clinical records and magnetic resonance imaging (MRI) findings of patients seen at a single institution was completed.

We identified 62 children and teenagers (mean age, 13.9 years; range, 8-18 years) who had a total of 101 bone bruises on MRI. The injuries occurred during a variety of organized and recreational sporting activities, the most common being football, basketball, and soccer. The majority (61.4%) of bone bruises occurred as a result of noncontact mechanisms. Patients reported a mean pain scale score of 6.3 of 10 (range, 2-10) on presentation. Frequent clinical findings included non-joint-line tenderness (64.5%), limited range of motion (58.1%), joint-line tenderness (54.8%), and positive meniscal signs (50.0%). The majority of bone bruises (61.4%) were located medially, and the most common bone bruise type was subcortical (58.4%), followed by medullary/reticular (35.6%) and articular impaction (5.9%). The only factor related to time to recovery was mechanism of injury; patients reporting a noncontact mechanism required significantly more time to recover than those reporting a contact mechanism (mean, 99.7 ± 74.8 vs 65.7 ± 38.8 days, respectively; F = 3.753, P = .049).

In this case series of 62 pediatric patients with non-anterior cruciate ligament (ACL) bone bruises, the majority occurred in the medial compartment, suggesting that these bone bruises result from a mechanism distinct from the pivot-shift mechanism, classically thought to cause ACL injuries.