Influence of Change in Echo Intensity of the Pretalar Fat Pad in Young Individuals With Chronic Ankle Instability

This study aimed to investigate the echo intensity (EI) of the pretalar fat pad (PFP) in young individuals with chronic ankle instability (CAI) and clarify the relationship between changes in the PFP and the clinical characteristics of CAI. Using the Identification of Functional Ankle Instability (IdFAI) scores, 26 limbs of 15 participants were divided into CAI (IdFAI score ≥11, male: eight limbs, female: six limbs, age: 21±1 years) and normal (IdFAI score <11, male: nine limbs, female: three limbs, age: 20±1 years) groups. The EI of the PFP was measured, and the luminosity ratio (LR) to the EI of the subcutaneous adipose tissue was calculated. To evaluate ankle joint stability and function, the fibulo-talar separation rate and weight-bearing lunge test (WBLT) values were measured. These parameters were compared between the two groups, and their correlations were statistically analyzed. The median IdFAI score in the CAI group was 15.5. The LR of the PFP was significantly higher in the CAI group than in the normal group (P<0.01). The fibulo-talar separation rate values were significantly higher (P=0.006), and the WBLT values were lower (P=0.011) in the CAI group. A moderate negative correlation was observed between the LR and WBLT values (r =-0.44, P=0.03). The LR of the PFP was high in the CAI group and was related to limited dorsiflexion of the ankle joint in the loaded position. Evaluating the entire ankle joint, including the PFP, is important, even for young individuals with mild CAI.