Diagnostic and therapeutic joint injections.

Joint injection is a useful tool in the diagnosis of intra-articular pathology that may improve diagnostic performance of computed tomography (CT) and magnetic resonance (MR) imaging. Historically, conventional arthrography under fluoroscopy was the first method to be used to image indirectly the intra-articular soft tissues, but with the advent of CT, CT arthrography offered better soft tissue depiction. The development of conventional MR allowed even better visualization of soft tissues, and in the early 1990s, MR arthrography surpassed CT arthrography in popularity. Joint injections may also be performed for therapeutic reasons with different drugs, such as corticosteroids, anesthetics, or hyaluronic acid, which have been shown to provide pain relief in various circumstances. In this article, the technical principles for joint injection of the shoulder, knee, elbow, hip, ankle, and wrist, used for therapeutic or diagnostic reasons, are discussed. Indications, expected benefits, and risks are also analyzed.