Ultrasound Relationship of Plantar Fat and Predislocation Syndrome.

Background: Plantar fat plays a crucial role in protecting and cushioning the metatarsals. Its degeneration is a risk factor for the development of metatarsalgia and, consequently, predislocation syndrome.

Objectives: To evaluate the relationship between plantar fat thickness and predislocation syndrome in an adult population, and to determine a possible association between a decrease in forefoot plantar fat and the presence of symptoms.

Material and methods: A retrospective observational study was conducted, including records of patients who visited the podiatry clinic between December 2022 and December 2023. Fifty complete records were selected, divided into two groups, one healthy and one pathological, aged between 18 and 70 years. An ultrasound examination of the plantar area of the second metatarsophalangeal joint was performed to assess the thickness of the fat and plantar plate.

Results: The analysis of the 50 records, divided into healthy and pathological groups, reveals significant differences in the thickness of plantar fat and the plantar plate between the two groups. Subjects with predislocation syndrome have a significantly lower plantar fat thickness (0.566 cm) compared to the healthy group (0.941 cm) and also show a greater thickness of the plantar plate (0.359 cm vs. 0.244 cm). Statistical tests confirm these differences with high significance (p < 0.001). The ROC curve shows that plantar fat thickness is a good predictor of predislocation syndrome, with an area under the curve (AUC) of 0.923, emphasizing the utility of this measure in identifying the condition.

Conclusions: Preliminary studies suggest that a reduction in plantar fat increases the predisposition to develop predislocation syndrome at the level of the second metatarsophalangeal joint.