The Celery Stalk Sign: An Indicator of Mucoid Cyst of Anterior Cruciate Ligament

Abstract

Mucoid cyst of the anterior cruciate ligament is a rare condition that is often overlooked [1,2]. It is a newly formed cystic formation consisting of one or more cavities containing very viscous mucoid fluid and surrounded by a fibro conjunctive wall [2], described by Bergin et al as an uncommon form of mucoid degeneration [1]. Its prevalence in magnetic resonance imaging (MRI) is 0.4 to 1.3% with a male predominance and an average age between 40 and 50 years old [1]. The clinical picture at the beginning is asymptomatic, the evolution is characterized by gonalgia of progressive intensity often posterior in the popliteal fossa [1,2], associated with a limitation of flexion and/or extension with sometimes episodes blocking [1,2]. The physical examination is poor and not very specific, a history of acute trauma or repetitive strain injuries are often involved [1,2]. Magnetic resonance imaging (MRI) is the gold standard for diagnosis [1,2]. It appears in the form of a cystic lesion, fusiform of liquid signal, filling the intercondylar notch and oriented in the long axis of the anterior cruciate ligament which appears widened in a fan “like a stalk of celery” [1,2]. The evolution can be marked by the rupture of the cyst [1] hence the importance of early diagnosis and adequate management. Arthroscopic resection is the treatment of choice given its minimally invasive nature, its good functional results and a nearzero recurrence rate [1,2].