Comparison of the Morphological Characteristics of the Foot and Ankle Muscles of Healthy Individuals and Those with Chronic Ankle Instability

BACKGROUND: The most prominent feature of chronic ankle instability (CAI) is muscle weakness, which results from muscle atrophy. Although many studies have been conducted on CAI, studies that have identified the morphological characteristics of the foot and ankle muscles are limited. The current study aims to identify the changes in morphology of the foot and ankle muscles of superficial posterior compartment in individuals with CAI. METHODS: A cross-sectional study of 100 individuals 50 healthy (43 males and seven females, age: 23.26 +/- 2.38 years, height: 175.86 +/- 7.37 cm, weight: 72.15 +/- 11.68 kg), and 50 with CAI (27 males and 23 females, age: 23.28 +/- 2.79 years, height: 172.27 +/- 8.27 cm, weight: 70.36 +/- 15.53 kg) participated in this study. The morphology of foot and ankle muscles (cross-sectional area and thickness) was measured using a portable wireless ultrasound diagnostic device. For statistical analysis, an independent t -test was used to compare the morphological characteristics between healthy and CAI. RESULTS: Significant differences were found between the morphology of the foot and ankle muscles of the CAI and healthy groups. The CAI group showed a significant decrease compared to the healthy group (P<0.05), but a significant increase in the flexor hallucis longus (P<0.05). CONCLUSIONS: Individuals with chronic ankle instability showed atrophy of the foot and ankle muscles, but hypertrophy of the flexor hallucis muscle compared to the healthy group. In conclusion, this study suggests that clinicians could apply rehabilitation programs targeting these muscles to improve atrophied muscles in individuals with CAI.