Assessment of menisci and ligamentous injuries of the knee on magnetic resonance imaging: correlation with arthroscopy.

OBJECTIVE To evaluate the validity of MRI, in the assessment of the meniscal and cruciate ligamenteous injuries of the knee joint and comparison with arthroscopic findings. METHODS A one year prospective cross-sectional study from January 2006 to January 2007, was performed on 50 patients (32 males & 18 females) with knee injury presenting at the orthopedic unit of AKUH. The patients were referred to radiology department for MRI evaluation and arthroscopy. RESULTS The sensitivity, specificity and accuracy for MRI of the menisci and ligaments were as follows: medial meniscus resulted in 100% sensitivity, 69.27% specificity, 90% PPV, 100% NPV and 92% accuracy: lateral meniscus resulted in 87.5% sensitivity, 88.23% specificity, 77% PPV, 93% NPV and 88% accuracy: anterior cruciate ligament resulted in 86.67% sensitivity, 91.43% specificity, 81% PPV, 94% NPV and 88% accuracy; posterior cruciate ligament resulted in 100% sensitivity, 95.83% specificity,50% PPV, 100 NPV and 96% accuracy. CONCLUSION Magnetic resonance imaging is a good, accurate and non invasive modality for the assessment of menisci and ligamenteous injuries. It can be used as a first line investigation in patients with soft tissue trauma to knee.