Characteristic pattern and management of intra-articular knee lesions in different pediatric age groups.

Posttraumatic hemarthrosis of the knee joint usually leads to arthroscopy. In a retrospective study we defined an age-specific spectrum of injuries and, subsequently, assigned an age-dependent diagnostic management for children up to 16 years. From January 1986 to December 1996, 1,273 patients up to 16 years of age with knee trauma presented to the emergency department. Overall, soft-tissue lesions prevailed (82%). Hemarthrosis occurred in only 18.0%. The patients were classified in three groups: group 1 (528 children younger than 10 years of age) with hemarthrosis in only 5.7% (mainly metaphyseal fractures and patellar dislocations), group 2 (207 preadolescents from 11 to 12 years of age) with hemarthrosis in 17.9% (patellar dislocations and fractures), and group 3 (538 adolescents between the age of 13 and 16 years) with hemarthrosis in 30.3% (main findings were intra-articular fractures and patellar dislocations, additionally, 16 ligamentous and two meniscal lesions). Correspondingly, physical examination, conventional radiography, and magnetic resonance imaging (most appropriate diagnostic tool for patellar dislocation) were sufficient to reveal injuries in children up to 13 years of age. Arthroscopy was predominantly justified in those older than 13 years of age, but only if it leads to therapeutic consequences.