Knee and Ankle Imaging

This issue of Seminars in Musculoskeletal Radiology accompanies the annual meeting of the European Society of Skeletal Radiology, held in Zurich, Switzerland, June 9 to 11, 2016, that focuses on the knee and ankle.

Imaging of the knee is very commonly performed and many abnormalities are encountered, but the correct assessment concerning clinical relevance remains tricky. Underlying anatomical considerations there is much emphasis on the preoperative evaluation and the challenges of postoperative evaluation of the knee. The knee section of this issue begins with a comprehensive article that illustrates the differences in the evaluation of chronic knee pain using MRI and single-photon emission tomography/computed tomography (CT). Seven articles follow that address the various knee ligaments. The emphasis on ligaments is related to recent advances in knowledge of their anatomy and new therapy. Some of these topics (e.g., the role of the anterolateral ligament) are highly debated among both radiologists and orthopedic surgeons.

Ankle imaging is challenging for most radiologists because it is not performed as often as knee imaging. The anatomy is more complicated and the literature relatively sparse. Two articles about the medial supporting structures of the ankle offer practical advice about addressing the relatively common but complicated issue of the deltoid ligament and the spring ligament. The next article describes the role of imaging to identify the cause of postsurgical symptoms and to direct appropriate image-guided intervention. The final article addresses the very promising dual-energy CT technique in the evaluation of gout. Dual-energy CT plays an increasing role in the assessment of gout in both the knee and foot. Based on its high diagnostic performance, dual-energy CT has been included in the 2015 American College of Rheumatology/European League Against Rheumatism classification criteria for gout.

I hope readers find the articles as useful and interesting as I do. I would like to thank all the authors in this issue for their excellent contributions.