An intra-articular knee cyst in a 2-year-old associated with an aberrant anterior cruciate ligament

Intra-articular ganglia of the knee occur infrequently, with an overall incidence estimated to be from 0.2 to 1.9%. To date, the youngest patient reported with an intra-articular ganglion was an adolescent. In this paper, we describe a 2-year-old patient with a massive intra-articular knee cyst and an aberrant anterior cruciate ligament (ACL) origin. The cyst was successfully treated with arthroscopic debridement. Proposed pathology and treatment recommendations for intra-articular cysts are reviewed.