Knee MRI: Meniscus, Ligaments & Cartilage
The workhorse joint study. MRI reads the meniscus, ligaments and cartilage; a signal change only matters if it reaches a surface or fits the story.
Menisci
A meniscal tear is diagnosed when abnormal signal reaches the articular surface. Intrasubstance high signal that doesn’t reach a surface is usually degeneration, not a surgical tear, a common source of over-calling.
Watch for the bucket-handle tear (displaced fragment; “double PCL” sign) and root tears; both change management.
Ligaments
- ACL: discontinuity, abnormal angle/signal; look for the classic pivot-shift bone bruises (lateral femoral condyle + posterolateral tibia) and associated Segond fracture.
- PCL & collaterals: assessed for sprain vs complete tear; MCL/LCL and posterolateral corner.
Cartilage & bone
MRI grades chondral defects and detects bone-marrow oedema, seen in acute injury (bone bruise), stress reaction, and subchondral disease. Quantitative cartilage mapping (T2/T1rho) can flag early degeneration before defects appear.
Sources
- Nikken JJ, Oei EH. Magnetic resonance imaging of the knee (clinical reviews on meniscal and ligament assessment).
Educational summary for clinicians; correlate with symptoms and examination. Not medical advice.
Contents