Pediatric knee MR imaging: pattern of injuries in the immature skeleton.

PURPOSE: To evaluate the frequency of various cartilaginous and ligamentous knee injuries with magnetic resonance (MR) imaging in a large pediatric population.

MATERIALS AND

METHODS

The authors reviewed 104 consecutive MR imaging studies acquired in patients 4-18 years of age with open physes. Frequency of various injuries was compared by using a chi 2 test. The frequency of each injury was compared with published adult data by using the Student t test. Arthroscopic follow-up in 30 patients was used to calculate sensitivity and specificity.

RESULTS

The medial meniscus was found to be injured more frequently than the lateral meniscus or the anterior cruciate ligament (ACL). Both menisci were injured less frequently than in adults. Sensitivity and specificity of MR imaging for meniscal tears were 83% and 95%, respectively, and for ACL tears were 64% and 94%, respectively.

CONCLUSIONS

These results show that medial meniscal tears are the most common cartilaginous or ligamentous injury in children and adolescents. The frequency of specific injuries, however, is different from that in adults.