The knee is a common area of the body to undergo interventional procedures. This article discusses image-guided interventional issues specific to the knee area. The soft tissues in and around the knee are frequently affected by sportrelated injuries and often need image-guided intervention. This article details the specific technical issues related to intervention in these soft tissues, including the iliotibial tract, fat pads, patellar tendon and other tendons, bursae and the meniscus. Most often, simple procedures such as injection and aspiration are performed without image guidance. Rarely image-guided diagnostic arthrography and therapeutic joint injections are necessary. The technique, indications and diagnostic considerations for arthrography are discussed in this article. Primary bone and softtissue tumours may involve the knee and adjacent soft tissues. Image-guided biopsies are frequently necessary for these lesions; this article details the technical issues related to image-guided biopsy around the knee. A number of newer ablation treatments are now available, including cryoablation, high-frequency ultrasound and microwave ablation. Radiofrequency ablation, however, still remains the most commonly employed ablation technique. The indications, technical and therapeutic considerations related to the application of this technique around the knee are discussed here. Finally, we briefly discuss some newer, but as of yet, unproven image-guided interventions for osteochondral lesions and Brodie's abscess.
INTRODUCTIONThe knee is one of the commonest joints affected by osteoarthritis and other internal derangements, such as ligament and meniscal pathology, which may need imageguided and surgical management. The tissues around the knee are also a common site for bone tumours and intervention in the form of biopsy or ablation is often performed around the knee. Interventions such as injections are routinely performed in the knee and, in most instances, are performed in the outpatient setting without any image guidance. In this article, we discuss issues related to imageguided intervention specific to the knee joint. Detailed descriptions of the techniques and the merits of most of the procedures are described elsewhere in this issue. We also discuss newer techniques such as drainage of abscess and retrograde drilling of osteochondral lesions, even though there is sparse literature on these procedures and the evidence is limited currently.