A 22-year-old male athlete presents with acute right knee pain and mechanical locking after a twisting injury during football. Clinical examination reveals joint line tenderness and a positive McMurray test. MRI shows a vertical longitudinal tear with the inner meniscal fragment displaced into the intercondylar notch, as marked **A** in the diagram. The displaced fragment lies anterior and parallel to the posterior cruciate ligament on sagittal imaging. Which of the following is the most characteristic MRI finding associated with this tear pattern?
A. Fragment in the intercondylar notch visible only on coronal imaging
B. Double PCL sign — the displaced fragment appears anterior and parallel to the native PCL
C. Disproportionate posterior horn sign with fragmentation
D. Absent bow-tie sign — loss of the normal double bow-tie configuration of the meniscal body on sagittal slices
Explanation
Why "Double PCL sign" is right
The double PCL sign is the pathognomonic MRI finding for a medial bucket-handle meniscus tear. When the inner meniscal fragment (marked A) displaces centrally into the intercondylar notch, it lies anterior and parallel to the native PCL on sagittal imaging, creating the appearance of two PCL-like structures. This sign is highly specific for medial bucket-handle tears and directly reflects the anatomy of the displaced fragment shown in the diagram. Campbell's Operative Orthopaedics and AAOS guidelines identify this as the classic imaging hallmark of this tear pattern.
Why each distractor is wrong
Absent bow-tie sign: While this is a valid MRI finding in bucket-handle tears (loss of the normal double bow-tie configuration on 4-5 mm sagittal slices), it is less specific and can occur in other meniscal tears. The double PCL sign is more pathognomonic.
Disproportionate posterior horn sign with fragmentation: This is a secondary finding that may accompany bucket-handle tears but is not the most characteristic or specific sign for this particular tear pattern.
Fragment in the intercondylar notch visible only on coronal imaging: While the displaced fragment (marked A) is indeed visible in the intercondylar notch on coronal images, this finding alone is not specific to bucket-handle tears and can be seen in other displaced meniscal injuries. The sagittal double PCL sign is more distinctive.
High-YieldNEET PG
The double PCL sign on sagittal MRI (displaced fragment anterior and parallel to the native PCL) is pathognomonic for medial bucket-handle meniscus tear and should trigger urgent surgical referral.
