The double posterior cruciate ligament (PCL) sign appears on sagittal MRI images of the knee when a bucket-handle meniscal tear (medial meniscus in 80% of cases) flips towards the centre of the joint so that it comes to lie anteroinferior to the posterior cruciate ligament (PCL) mimicking a second smaller ligament.
A double posterior cruciate ligament sign from a torn medial meniscus can essentially only be seen in patients who have an intact anterior cruciate ligament (ACL) as this is required to prevent the flipped fragment from migrating further laterally, or not aligning parallel to the posterior cruciate ligament 1.
In a minority of patients, a lateral meniscus bucket handle tear, in the presence of torn anterior cruciate ligament, may also give rise to a double posterior cruciate ligament sign.
Identifying a double posterior cruciate ligament sign is highly specific (98-100%) but of variable sensitivity (27-53%) for the detection of displaced bucket-handle tears 1.
Associated signs include:
central meniscal fragment
Differential diagnosis
-
accessory meniscofemoral ligament (ligament of Humphrey)
smaller
closely approximated to the posterior cruciate ligament
normal medial meniscus
-
medial oblique meniscomeniscal ligament
normal medial meniscus
Unable to process the form. Check for errors and try again.