MRI appearance of retrocalcaneal bursitis and rheumatoid nodule in a patient with rheumatoid arthritis

The Kager's fat pad radiological anatomy revised

Purpose

The aim of the study was to map connections within the Kager’s fat pad between the structures which limit it.

Methods

A retrospective re-review of 200 ankle magnetic resonance imaging (MRI) examination was conducted. Connections within the Kager’s fat pad between the superior peroneal retinaculum, the fibulotalocalcaneal ligament, the posterior talocalcaneal ligament, the flexor hallucis longus, the paratenon of the Achilles tendon, the flexor retinaculum and bones were studied and a model of the connections was constructed.

Results

The superior peroneal retinaculum was directly connected with the fibulotalocalcaneal ligament in 85.5% of cases, the lateral part of the paratenon in 82.5%, the processus posterior tali in 78.5%, the posterior talofibular ligament in 32%, the flexor retinaculum in 29.5% and the anterior talofibular ligament in 9%.

The fibulotalocalcaneal ligament was connected with the paratenon (on the medial side 88.5%, on the lateral side 68.5%), the flexor retinaculum in 70%, the posterior process of the talus in 79%, the osteofibrosus tunnel for the flexor hallucis longus in 53%, the posterior talofibular ligament in 43.5% and the calcaneofibular ligament in 10.5%.

The posterior talocalcaneal ligament was connected with the fibulotalocalcaneal ligament in 71%, with the osteofibrosus tunnel for the flexor hallucis longus in 76.5%, with the flexor retinaculum in 70%. The plantaris tendon showed projection to the crural fascia in 34 of % cases.

Conclusion

In the Kager’s fat pad there are present more connections than previously reported. All the connections unit at the level of the posterior process of the talus.

Traumatic and non-traumatic bone marrow edema in ankle MRI: a pictorial essay

Bone marrow edema (BME) is one of the most common findings on magnetic resonance imaging (MRI) after an ankle injury but can be present even without a history of trauma. This article will provide a systematic overview of the most common disorders in the ankle and foot associated with BME.

The presence of BME is an unspecific but sensitive sign of primary pathology and may act as a guide to correct and systematic interpretation of the MR examination. The distribution of BME allows for a determination of the trauma mechanism and a correct assessment of soft tissue injury. The BME pattern following an inversion injury involves the lateral malleolus, the medial part of the talar body, and the medial part of the distal tibia. In other cases, a consideration of the distribution of BME may indicate the mechanism of injury or impingement. Bone in direct contact with a tendon may lead to alterations in the bone marrow signal where BME may indicate tendinopathy or dynamic tendon dysfunction. Changed mechanical forces between bones in coalition may lead to BME. Degenerative changes or minor cartilage damage may lead to subchondral BME. Early avascular necrosis, inflammation, or stress fracture may lead to more diffuse BME; therefore, a detailed medical history is crucial for correct diagnosis.

A systematic analysis of BME on MRI can help to determine the trauma mechanism and thus assess soft tissue injuries and help to differentiate between different etiologies of nontraumatic BME.

Thenar lumps: a review of differentials

Most soft-tissue lumps in the hand are benign, with ganglions being the commonest, but in the thenar region, solid soft-tissue masses are more common than a ganglion. In this review, we focus on soft-tissue lesions (neoplastic and non-neoplastic) presenting as a palpable lump in this region. A specific diagnosis can often be reached using ultrasonography and/or magnetic resonance imaging. Most of these lesions are managed in local hospitals or primary care, whereas some are referred to specialist centres. This review article will help both general and musculoskeletal radiologists to diagnose and characterise these lesions, provide a guide for further imaging, and provide an insight into imaging features that may need specific investigations such as core biopsy, tertiary referral, and further review at multidisciplinary meetings.

Retrocalcaneal pain after the repair of acute Achilles tendon rupture

Pain in the posterosuperior portion of the calcaneus can be caused by a retrocalcaneal bursitis, enlargement of the superior bursal prominence of the calcaneus, insertional Achilles tendinopathy, stress fracture of the calcaneus, or inflammation of an adventitious bursa between the Achilles tendon and the skin. Hypertrophied tendon impinging on the posterosuperior calcaneal tuberosity can be a cause of retrocalcaneal pain after repair of acute rupture of the Achilles tendon. This can be effectively treated by endoscopic calcaneoplasty.

LEVELS OF EVIDENCE

Therapeutic, Level IV, Case Report.