[A woman with a locked knee]

Area of Science:

• Orthopedic Surgery
• Sports Medicine
• Radiology

Background:

• Meniscal tears are common knee injuries, often resulting from twisting motions.
• Bucket-handle tears represent a specific type of meniscal tear where a fragment displaces.
• Knee locking is a significant symptom indicating potential intra-articular derangement.

Observation:

• A 25-year-old female experienced acute left knee locking following an assertiveness training session.
• Magnetic Resonance Imaging (MRI) revealed a bucket-handle tear of the medial meniscus.
• The displaced meniscus fragment lodged within the intercondylar fossa.

Findings:

• The medial meniscus dislocation into the intercondylar fossa simulated the appearance of a second posterior cruciate ligament (PCL).
• This characteristic imaging finding is termed the 'double PCL sign'.
• The 'double PCL sign' is a rare radiographic manifestation of meniscal displacement.

Implications:

• Accurate diagnosis of displaced meniscal tears is crucial for appropriate orthopedic management.
• The 'double PCL sign' on MRI aids in identifying unusual meniscal pathologies.
• Prompt surgical intervention may be necessary to restore knee function and prevent further damage.