LATERAL-COMPARTMENT BONE CONTUSIONS IN ADOLESCENTS WITH INTACT ANTERIOR CRUCIATE LIGAMENTS

PURPOSE: To determine how often lateral-compartment bone contusions ar e seen on magnetic resonance (MR) images of knees in adolescents with intact anterior cruciate ligaments (ACLs). MATERIALS AND METHODS: MR i mages obtained in 53 adolescent patients (30 male, 23 female; aged 10- 20 years) were reviewed to detect bone contusions in the posterolatera l tibial plateau or the lateral femoral condyle. ACLs were also evalua ted with accepted criteria for the diagnosis of ligamental disruption. Only patients referred for evaluation of a knee injury or mechanical symptoms were included. RESULTS: Five patients with bone contusions ha d an intact ACL at MR imaging. One of the five had arthroscopic confir mation. Fifteen other patients had complete ACL disruptions: 13 of the se patients had typical bone contusions; the other two had no bone abn ormalities but had chronic ACL tears. Thus, 28% of the 18 patients wit h typical bone contusions had intact ACLs. CONCLUSION: Adolescents may have the same pattern of contusions as adults but may maintain an int act ACL owing to increased ligamentous laxity.