Acute traumatic knee effusions in children and adolescents.

A prospective analysis was completed during a 6-month period to identify all patients, age 18 years or younger, who presented for evaluation of their knee effusion. There were 44 injured knees in 44 patients. There were a total of 55 diagnoses: 16 (29%) anterior cruciate ligament (ACL) injuries, 16 (29%) meniscal tears, 14 (25%) patellofemoral subluxations or dislocations, 3 (5%) medial collateral ligament sprains, 2 (4%) patellar osteochondral fractures, 2 (4%) retinacular injuries, 1 (2%) posterior cruciate ligament rupture, and 1 (2%) tibial eminence fracture. Girls had 11 of the 14 patellofemoral injuries; 58% of the girls had effusions secondary to patellofemoral pathology compared with 12% of the boys. Boys had 10 of the 16 meniscal tears and 13 of the 16 ACL tears. Fifty-two percent of boys had an injury to the ACL and 44% had an injury to a meniscus. In contrast, 16% of girls had an ACL injury and 32% had meniscal tears. ACL injuries, meniscal tears, and patellofemoral pathology accounted for 87% (48/55) of the diagnoses. Girls were more likely to have patellofemoral pathology; boys were more likely to have ACL and meniscal tears.