Physicians diagnosing and managing knee injuries have become familiar with the lateral capsule sign, or Segond fracture on radiography. The Segond fracture is considered highly suggestive of an anterior cruciate ligament (ACL) tear in the adult population. This conclusion is not as well described in the pediatric patient. Recent anatomic studies have confirmed the presence of the anterolateral ligament (ALL), a structure described by Dr. Segond, and hypothesized to be the etiology of the lateral capsular avulsion. Although case reports of Segond fractures with an intact ACL in pediatric patients have been presented, there is usually a concomitant rotatory instability, tendinous injury, physeal fracture or posterolateral disruption. It is not currently clear the role that the ALL plays in the setting of Segond fracture with an intact ACL. We present a case of an isolated Segond fracture and briefly review the literature relating to this diagnosis. The literature suggests that a Segond fracture without an ACL tear is more common in the pediatric age group compared to adults. Our unique case is the presence of an isolated Segond fracture in a pediatric athlete.
Keywords: ACL tear; Lateral capsule sign; Segond; anterolateral ligament.