The Knee: The Menisci

The knee is one of the most frequently imaged peripheral joints on MR imaging. Plain radiographs are the initial modality to evaluate the knee. MR imaging is subsequently used to assess acute and chronic internal and external derangements of the knee. Due to the excellent soft-tissue resolution and tissue characterization on MR imaging, it is the preferred modality to evaluate the menisci and aid in the management of meniscal pathology. Trauma is a very common indication for MR imaging of menisci. Timely diagnosis of meniscal tears is essential in directing appropriate management before the onset of early osteoarthritis from loss of the adjacent articular cartilage. Therefore, the radiologist must have an in-depth understanding of the types of meniscal injuries on MR imaging, their classification, and interpretation. Furthermore, correlation with clinical history helps identify age-related horizontal asymptomatic tears and prevent unnecessary surgeries (Boden SD, Davis DO, Dina TS, Stoller DW, Brown SD, Vailas JC et al (1992) A prospective and blinded investigation of magnetic resonance imaging of the knee: abnormal findings in asymptomatic subjects. Clin Orthop Relat Res (282):177–185). This chapter focuses on MR techniques to image the menisci, normal meniscal anatomy, and meniscal pathology.