Sonographic visibility of the sinus tarsi with a 12 MHz transducer

The frondiform ligament sling: a sonographic landmark for injection into the sinus tarsi

Localisation and injection of the sinus tarsi can be challenging, particularly for the less experienced musculoskeletal sonographer/practitioner. The inferior extensor retinaculum arises from the sinus tarsi in the form of three roots (medial, intermediate and lateral) which are collectively termed the frondiform ligament. This is readily identified on ultrasound and can be used as a reference point to aid the safe delivery of injectate material into the sinus tarsi. This article describes the technique and its anatomical basis.

Adult Acquired Flatfoot Deformity: Anatomy, Biomechanics, Staging, and Imaging Findings

Adult acquired flatfoot deformity (AAFD) is a common disorder that typically affects middle-aged and elderly women, resulting in foot pain, malalignment, and loss of function. The disorder is initiated most commonly by degeneration of the posterior tibialis tendon (PTT), which normally functions to maintain the talonavicular joint at the apex of the three arches of the foot. PTT degeneration encompasses tenosynovitis, tendinosis, tendon elongation, and tendon tearing. The malaligned foot is initially flexible but becomes rigid and constant as the disorder progresses. Tendon dysfunction commonly leads to secondary damage of the spring ligament and talocalcaneal ligaments and may be associated with injury to the deltoid ligament, plantar fascia, and other soft-tissue structures. Failure of multiple stabilizers appears to be necessary for development of the characteristic planovalgus deformity of AAFD, with a depressed plantar-flexed talus bone, hindfoot and/or midfoot valgus, and an everted flattened forefoot. AAFD also leads to gait dysfunction as the foot is unable to change shape and function adequately to accommodate the various phases of gait, which require multiple rapid transitions in foot position and tone for effective ambulation. The four-tier staging system for AAFD emphasizes physical examination findings and metrics of foot malalignment. Mild disease is managed conservatively, but surgical procedures directed at the soft tissues and/or bones become necessary and progressively more invasive as the disease progresses. Although much has been written about the imaging findings of AAFD, this article emphasizes the anatomy and function of the foot's stabilizing structures to help the radiologist better understand this disabling disorder. Online supplemental material is available for this article. ^©RSNA, 2019.

Ultrasound Features of Ankle Retinacula: Normal Appearance and Pathologic Findings

Disorders of retinacula are frequent in acute and repetitive microtrauma of the ankle. Ultrasound (US), thanks to its spatial resolution and dynamic capabilities, is routinely used in the evaluation of the posttraumatic ankle for accurate delineation of ligaments and tendons. In addition, US can provide a depiction of normal retinacula and a detailed assessment of their pathologic changes. An accurate US assessment of ankle retinacula is helpful in choosing the proper treatment. In this pictorial essay, we briefly review the normal anatomy of ankle retinacula, describe their normal US appearance, and present a wide range of US pathologic abnormalities.

Sonographic and radiographic findings of posterior tibial tendon dysfunction: a practical step forward

The purpose of this article is to describe the sonographic and radiographic findings in the diagnosis and treatment of posterior tibial tendon dysfunction. Ultrasound and radiographs play a crucial role in the diagnosis of posterior tibial tendon dysfunction and in imaging the postoperative changes related to posterior tibial tendon dysfunction. Early detection and diagnosis of posterior tibial tendon dysfunction is important in helping to prevent further progression of disease, obviating the need for more invasive and complex procedures.