Presentation
Clicking and knee pain. No significant osteoarthritis on a prior recent knee radiograph.
Patient Data
The central third of the medial meniscus is extruded with a complete tear of the medial meniscus posterior root, as evidenced by a 'ghost' meniscus on the sagittal sequences.
The proximal aspects of the MCL and fibular collateral ligament are both mildly thickened and return intermediate fluid signal, indicating a low grade sprains.
Focal full thickness articular cartilage fissures within the central trochlea with associated subchondral cystic change, best demonstrated on the sagittal sequences.
Arrows point to the complete radial tear of the medial meniscus on the different imaging planes. The 'ghosting' is demonstrated on the sagittal sequences.
Case Discussion
A ghost meniscus signifies a complete radial or root avulsion tear, where a gap in the meniscal tissue causes the meniscus to disappear then reappear 1. If the central third of a meniscus is extruded, a complete radial tear/ root avulsion should be suspected.