Échographie dynamique

Dynamic high-resolution US of ankle and midfoot ligaments: normal anatomic structure and imaging technique

The ankle is the most frequently injured major joint in the body, and ankle sprains are frequently encountered in individuals playing football, basketball, and other team sports, in addition to occurring in the general population. Imaging plays a crucial role in the evaluation of ankle ligaments. Magnetic resonance imaging has been proven to provide excellent evaluation of ligaments around the ankle, with the ability to show associated intraarticular abnormalities, joint effusion, and bone marrow edema. Ultrasonography (US) performed with high-resolution broadband linear-array probes has become increasingly important in the assessment of ligaments around the ankle because it is low cost, fast, readily available, and free of ionizing radiation. US can provide a detailed depiction of normal anatomic structures and is effective for evaluating ligament integrity. In addition, US allows the performance of dynamic maneuvers, which may contribute to increased visibility of normal ligaments and improved detection of tears. In this article, the authors describe the US techniques for evaluation of the ankle and midfoot ligaments and include a brief review of the literature related to their basic anatomic structures and US of these structures. Short video clips showing dynamic maneuvers and dynamic real-time US of ankle and midfoot structures and their principal pathologic patterns are included as supplemental material. Use of a standardized imaging technique may help reduce the intrinsic operator dependence of US. Online supplemental material is available for this article.

Practical US of the forefoot

Disorders affecting the forefoot are common in the clinical practice. Accurate history and physical examination are the mainstays of diagnosis but imaging modalities are frequently obtained to confirm the clinical suspicion and plan appropriate treatment. In this article we will present the ultrasound (US) technique of examination of the forefoot followed by a brief description of the normal US anatomy and of US appearance of the most frequent forefoot disorders; rheumatoid arthritis, osteoarthritis, overuse arthropathy, Morton neuromas, bursitis, mucoid cysts, foreign bodies, bone disorders.

The tibialis posterior tendon

The tibialis posterior tendon is the largest and anteriormost tendon in the medial ankle. It produces plantar flexion and supination of the ankle and stabilizes the plantar vault. Sonographic assessment of this tendon is done with high-frequency, linear-array transducers; an optimal examination requires transverse retromalleolar, longitudinal retromalleolar, and distal longitudinal scans, as well as dynamic studies. Disorders of the posterior tibial tendon include chronic tendinopathy with progressive rupture, tenosynovitis, acute rupture, dislocation and instability, enthesopathies. The most common lesion is a progressive "chewing gum" lesion that develops in a setting of chronic tendinopathy; it is usually seen in overweight women over 50 years of age with valgus flat feet. Medial ankle pain must also be carefully investigated, and the presence of instability assessed with dynamic maneuvers (forced inversion, or dorsiflexion) of the foot. Sonography plays an important role in the investigation of disorders involving the posterior tibial tendon.

Ultrasound approach to the canine distal tibia and trochlear ridges of the talus

The aim of the present study was to evaluate to what extent the distal tibia and the trochlear ridges of the talus can be examined with ultrasound (US) in the dog and to establish a protocol for an optimal US examination of these ridges. Six hind limbs of deceased adult mixed-breed dogs were used. In two limbs, needles were placed using US guidance on the trochlea of the talus, just dorsal to and plantar to the distal tibia: one with the tarsal joint in extension and one with the joint in flexion. Then mediolateral (ML) radiographs of both joints were made with the needle in place to determine the percentage of the trochlear ridge of the talus that can be seen using US imaging. An US examination of the tarsal joint was performed on the four other limbs using microconvex (8 MHz) and linear (12 MHz) transducers (Logiq 7) and compound imaging. A three-step protocol was performed including a dorsal approach with the limb extended and the linear transducer (step I), a plantar approach with the limb flexed and the linear transducer (step II), and a plantar approach with the limb flexed and the microconvex transducer (step III). After the US examination, the four limbs were frozen and sectioned, two in a transverse and two in a sagittal plane. Bony structures on the US images were matched with the corresponding anatomic sections. The distal tibia and both trochlear ridges of the talus were easily recognized on the US images using the proposed protocol. When combining the dorsal and plantar approaches, it was possible to visualize up to 75% of the trochlear ridges of the talus in the dog.

[Ankle and foot sprains: conventional radiography aspects]

Emergency departments frequently encounter pathology resulting from injury to the foot and ankle, with approximately 6000 case per day in France. In an ankle sprain, 85% of the lesions involve the lateral collateral ligament. Many other, much rarer, types of lesion with different therapeutic consequences can present, however. Interpretation of the initial conventional radiographs is vital to establishing the type lesion and to proposing adapted and rapid treatment. The objective of this article is to review the various osteoarticular and ligament injuries encountered in the foot and the ankle.

Échographie des nerfs périphériques — Deuxième partie : membre inférieur

On sonographic images, the peripheral nerves have a fibrillary structure, ribboned on longitudinal images and ovoid on cross-section images. The nerves travel between the muscle groups, often with blood vessels, or in canals. Recently improved ultrasound devices are able to investigate the peripheral nerves along their entire length, as far as the sonographer has thorough anatomical knowledge, rigorous technique, and, when searching for pathology, good clinical notions. As in Part I on sonography of the peripheral nerves of the upper limbs, published in this journal, the objective of this general review is to present normal and pathological echoanatomy of the peripheral nerves of the lower limbs in an educational way.

Le muscle du sportif

Traumatic muscular pathology is frequent in the athlete. Usually, these lesions heal spontaneously leaving no sequelae. One must be able to predict how long the healing process will last in order to avoid a long period of inactivity and to protect the patient from a recurrent tear. Medical imaging can define the precise location and severity of muscle traumas and detect critical elements that will delay complete repair. Sonography is the most useful and the least expensive imaging technique for analyzing muscular trauma. It provides a good study of muscle fibers, tendons, and aponeurosis but is limited in its poor visualization of the deep structures such as hamstring tendons and the difficulty in detecting muscular scar. MRI is the most sensitive imaging technique for analyzing muscular trauma. However, muscular fibers themselves are not visualized with MRI. It remains a secondary technique, adapted to the insufficiencies of sonography. Nevertheless, the exact place of medical imaging in traumatic muscular pathology remains and leaves the door open to many later studies.