Edematous processes within Kager fat pad: magnetic resonance imaging, gross anatomical, and histological studies in cadavers with clinical correlation

Ligaments of the os trigonum: an anatomical study

PURPOSE

The aim of the study was to examine the ligaments of the os trigonum.

METHODS

The ankle joint magnetic resonance imaging (MRI) of 104 patients with the os trigonum (experimental group) and 104 patients without the os trigonum (control group) were re-reviewed. The connections of the os trigonum and posterior talofibular ligament (PTFL), the fibulotalocalcaneal ligament (FTCL), the paratenon of the Achilles tendon, the posterior talocalcaneal ligament (PTCL), the osteofibrous tunnel of the flexor hallucis longus (OF-FHL) and the flexor retinaculum (FR) were studied.

RESULTS

The os trigonum is connected to structures. The posterior part of the PTFL inserted on the os trigonum in 85.6% of patients, whereas in all patients in the control group, the posterior part of the PTFL inserted on the posterior talar process (p < 0.05). The connection of the PTCL was seen in 94.2% of patients in the experimental group, while it was seen in 90.4% of patients in the control group (p > 0.05). The connection to the FTCL in the experimental group was 89.4%, while in the control group, it was 91.3% (p > 0.05). The communication with the paratenon was seen more often in the control group compared to that in the experimental group (31.7% vs. 63.8%, p < 0.001). The FTCL was prolonged medially into the FR in 85.6% of patients in the experimental group and in 87.5% of patients in the control group (p > 0.05). The flexor hallucis longus (FHL) run at the level of articulation between the os trigonum 63.5% and the posterior process of the talus 25% and less often on the os trigonum 11.5%.

CONCLUSION

The os trigonum is connected with all posterior ankle structures and more connections than previously reported.

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.

Correlation of morphologic and pathologic features of the various tendon groups around the ankle: MR imaging investigation

OBJECTIVE

To determine if a statistical association exists between abnormalities in one ankle tendon group (i.e., peroneal, medial flexor, or Achilles) and those in another.

MATERIALS AND METHODS

A retrospective analysis of 1.5-T and 3-T MR ankle examinations in 100 patients conducted between November 1, 2011 and April 1, 2012 was performed. The cross-sectional areas and diameters of the ankle tendons-Achilles (ACH), peroneus brevis (PB) and longus (PL), tibialis posterior (TP), flexor digitorum longus (FDL), and flexor hallux longus (FHL)-were measured, and the results were correlated to determine any association with the presence of qualitative abnormalities (tenosynovitis, tendinosis, and tendon tearing).

RESULTS

Subjects with larger diameters of the ACH tendon also revealed larger PL, TP, FDL, and FHL tendon diameters and sectional areas. Furthermore, subjects with larger PL tendons generally revealed larger flexor tendons and the same was also true when medial compartment tendons were individually assessed and measurements compared among the three of them. There was a statistically significant association with regard to the presence of tendon abnormalities (tendinosis, tenosynovitis, and tearing) in both the peroneal and medial flexor tendons. The presence of an abnormality in the ACH tendon correlated strongly with increasing diameters and areas of all the other ankle tendons except for the PB tendon.

CONCLUSIONS

There is an association between quantitative and qualitative abnormalities of one group of tendons when compared with the others with respect to the ACH, medial flexor, and peroneal tendons of the ankle, which is perhaps explained by a retinacular and fascial complex that anatomically connects the three groups.

Joint appendages: the structures which have historically been overlooked in arthritis research and therapy development

Rheumatologists have largely conceptualised joint disease in inflammatory and degenerative arthritis in terms of bone, cartilage and the synovial lining, but have tended to overlook other integral components of the joints which are attached close to joint margins. We discuss these structures under the umbrella term of 'appendages'. These structures include ligaments, tendons, entheses or joint insertions, regional fibrocartilages, bursae and other peri-articular joint structures including fat pads and nails. In this review, we highlight how these structures play key pathophysiological roles in inflammatory arthritis and we emphasise how an understanding of these structures is collectively important for both clinical practice and future rheumatological research.