Ankle and Foot: State of the Art

Ankle and foot disorders are common in the office practice of clinicians dealing with musculoskeletal disorders. They can affect a wide variety of patients and many different anatomical structures. The imaging of this region has dramatically improved over the past few years, and the high spatial resolution available makes a precise knowledge of the anatomy essential. New imaging methods and percutaneous treatments have also been developed. Therefore, a state-of-the-art review of current concepts and future perspectives in the imaging of the ankle and foot is of the utmost importance.

This issue begins with a description of the retinacula of the ankle and foot by my colleagues, Xavier Demondion et al. An awareness of the normal anatomy and imaging appearance of these structures is essential for the depiction of their injuries. Although these lesions may provide an explanation for chronic and unexplained residual pain after an injury, they are frequently overlooked or misdiagnosed in clinical practice. Bianchi et al then provide an excellent comprehensive discussion of peroneal tendon disorders. Although physical examination indicates the correct diagnosis in most patients, imaging, especially ultrasound (US), is almost always performed to confirm the diagnosis and evaluate additional findings that are often crucial in determining the choice between medical or surgical treatment.

The article by Calleja and Connell describes the imaging of Achilles tendon disorders and discusses in detail the various radiologically assisted treatment methods available at this time, which are steadily multiplying. The physician must be aware of them, even though further research is required to confirm the place of these therapeutic approaches and the criteria used to choose among them. Sonoelastography may also contribute valuable information in the assessment of the Achilles tendon, as aptly reported by Klauser et al in this issue. This newly introduced ultrasound technique evaluates tissue elasticity and may be of interest in delineating lesions such as edema, early mucoid degeneration, or small partial tears in tendons, which may be missed on conventional US imaging.

Next, the article by McNally and Shetty deals with the imaging findings of plantar fascial disorders and fully describes the various treatment options, such as corticosteroid injection and dry needling methods, and reports instructions for percutaneous interventions. Once again, it is obvious that percutaneous treatments for foot disorders are developing rapidly.

The diagnostic imaging of peripheral nerves in the distal lower extremity is a challenging task due to the small size and high number of terminal branches to be considered. Martinoli et al provide an outstanding article that fully demonstrates how a perfect knowledge of the anatomy is fundamental for the correct depiction of these disorders. Postoperative magnetic resonance (MR) imaging of the foot and ankle is also a difficult problem because the radiologist must deal with potentially misleading postoperative findings and susceptibility artifacts. Zanetti et al provide a fine description of the normal MR appearance after tendon repair, ligament repair, and Morton's neuroma resection. A knowledge of these features is essential for a correct reading of the imaging in such situations.

Finally, interpreting the radiological characteristics of neuropathic osteoarthropathy or osteomyelitis in a patient with a red-hot, massively swollen foot is also a challenge, and the final article by Schoots et al is especially useful in providing the tools for a careful differentiation between these two entities.

I would like to thank the editors for offering me the opportunity of acting as guest editor for this issue on the ankle and foot, which will, for the first time, be distributed to the participants in the annual European Society of Musculoskeletal Radiology meeting devoted to that same topic. It's been my pleasure to organize the meeting this year in Lille, France. I also wish to express my gratitude to the authors who contributed to this issue of Seminars in Musculoskeletal Radiology for their excellent contributions.