Teenage Female with Knee Pain and Instability

*To whom correspondence should be addressed: Dr. Patricia Jo University of Sakatchewan, Faculty of Medicine Email: [email protected] INTRoduCTIoN Congenital dislocation of the knee, resulting from an absence of the cruciate ligaments, is a condition affecting 0.017 per 1000 live births (1). Although very rare, it has drawn the attention of orthopaedic surgeons and radiologists because it is associated with other congential anomalies. This paper presents abnormalities that are isolated to the knee and without evidence of associated syndrome. The absent anterior cruciate ligament (ACL) is associated with a hypoplastic posterior cruciate ligament (PCL), a shallow femoral notch, and hypoplastic tibial spines seen with radiographic and magnetic resonance imaging. The objective of this article is to review the clinical presentation and imaging findings associated with congenitally absent ACL.