ABSTRACT
MRI is now established as a primary imaging modality in the knee. It is a simple technique which enables all the bony and soft tissue structures to be visualized noninvasively. But arthroscopy still has the upper hand in diagnosing the majority of different knee affections although invasively. Two hundred and fifty-three different knee lesions in 160 patients were evaluated by MRI and arthroscopy to judge importance of each. MRI is valuable in the investigation of patient with suspected internal derangement of the knee since it accurately assesses meniscal and ligamentous integrity, but detecting the shape of meniscal tears was not as accurate as by arthroscopy. MRI may be used to assess hyaline cartilage, synovium and bone in the complete spectrum of disorders of the knee, but it failed to differentiate between rheumatoid arthritis and pigmented villo-nodular synovitis which is a very easy and accurate by arthroscopy. Also, detection of various types of chondromalacia patillae and visualization of synovial plica could not be revealed. On the other hand, various kinds of extrasynovial lesions could not be accurately diagnosed by arthroscopy which is an easy job of MRI