Prospective analysis of uncomplicated bone bruises in the pediatric knee.

To determine the incidence of uncomplicated knee bone contusions in pediatric patients. MRI studies were obtained using either high-field (1.5 T) or mid-field strength magnets (0.2-0.3 T), identifying 48 pediatric patients suitable for study. Contusion location, size, and any ligamentous or meniscal injuries were recorded. Exclusionary criteria did not include plain film findings, the interval between injury to imaging, or history of patellar dislocation [Fulkerson (2002) 30:447-456]. Uncomplicated bone bruises were those occurring in the absence of other internal derangements of the knee, such as meniscal and ligament tears. Consensus imaging findings by two reviewing radiologists revealed a 25% incidence of uncomplicated bruises (12/48 patients). These bone bruises involved the lateral and medial knee compartments 56 and 44% of the time, respectively. Bruises of the lateral compartment were larger (2.4 cm) than those found in the medial compartment (1.8 cm). Given the high incidence of symptomatic but uncomplicated contusions identified in this study of a pediatric population, we suggest appropriate joint rest and follow-up without other intervention as a primary course of treatment.