The Kager’s fat pad radiological anatomy revised

Abstract

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.

Anatomical variations and interconnections of the superior peroneal retinaculum to adjacent lateral ankle structures: a preliminary imaging anatomy study

“…The IER, Eleni E. Drakonaki, Khaldun Ghali Gataa, Nektarios Solidakis, Paweł Szaro MRI (11) . The SPR connection to the calcaneofibular ligament and the Achilles paratenon was reported previously both in cadavers and MR imaging studies (12,21) . Other variations have been previously reported in cadavers, including the inferior due to its location, was found to serve as an intermediate station for connecting the SPR to the ATFL.…”

“…However, there is scarce evidence on the existence of these connections in MR studies. In a previous MR study, we documented SPR connections to the fibulotalocalcaneal ligament, the posterior talofibular ligament, and the flexor retinaculum via the fibulotalocalcaneal ligament (12) . The SPR-ATFL connection in that study was found in only 9% of cases, which is a lower proportion than in the current study.…”

“…SPR connections are essential components of a functional complex at the lateral malleolus level (12,27) . Statistically significant differences in the occurrence of connections revealed on MRI between the ATFL and PTS were noticed before between groups of single and double fascicular ATFL and CFL (11) .…”

“…Interconnections of the SPR to the lateral ankle structures have not been previously reported on US, and limited literature is available using MR (12) .…”

The double fascicular variations of the anterior talofibular ligament and the calcaneofibular ligament correlate with interconnections between lateral ankle structures revealed on magnetic resonance imaging

“…Previously proven connections between the lateral ligament complex of the ankle with ligaments in the Kager's fat pat may indicate the existence of some functional ligamentous-fascial units 28 where the ligament complex is one part of the entirety. The presence of interconnections between the lateral ankle ligaments explain the concomitant nature of lateral ankle ligament injuries, making them like the deltoid ligament or spring ligament complex; despite having parts, it is challenging to separate them from each other 10,29 .…”