Abstract
OBJECTIVE: The Single Leg Squat (SLS) task is an effective tool for assessing clinical, biomechanical, and athletic performance. However, the short-term biomechanical changes in SLS for patients with Femoroacetabular Impingement Syndrome (FAIS) post-surgery remain unclear. This study aims to evaluate the kinematic changes of the hip, knee, and ankle joints during single-leg squats at 3 and 6 months post-surgery in FAIS patients. METHODS: A total of 20 participants were included, comprising 10 FAIS patients and 10 age-, gender-, and BMI-matched healthy controls. Kinematic data were collected throughout the squat cycle using motion capture and force plates. Kinematic changes in the hip, knee, and ankle joints were analyzed. Repeated measures ANOVA was used to compare differences between 3 months, 6 months post-surgery, and baseline, while independent samples t-tests were used to compare baseline, 3 months post-surgery, 6 months post-surgery, and the matched healthy control group. RESULTS: Compared to pre-surgery, the hip flexion angle at 3 months post-surgery was significantly lower than that of the healthy control group (54.18° vs 83.29°, p=0.026). The hip adduction angle at 3 months post-surgery was significantly lower than baseline (5.32° vs 11.66°, p=0.013), 6 months post-surgery (5.32° vs 8.45°, p=0.005), and the healthy control group (5.32° vs 11.24°, p=0.030). The hip adduction angle at 6 months post-surgery was also significantly lower than baseline (8.45° vs 11.66°, p=0.004). Additionally, the ankle dorsiflexion angle at baseline was significantly lower than at 3 months post-surgery (11.21° vs 15.16°, p=0.006), 6 months post-surgery (11.21° vs 15.66°, p=0.001), and the healthy control group (11.21° vs 18.51°, p=0.002). The knee flexion angle at 3 months post-surgery was significantly lower than that of the healthy control group (63.57° vs 79.85°, p=0.016). CONCLUSION: FAIS patients exhibited limited ankle dorsiflexion pre-surgery, which showed significant improvement post-surgery. At 3 months post-surgery, the hip adduction angle, hip flexion angle, and knee flexion angle were all lower, indicating an unstable state of the lower limb joints, which significantly improved by 6 months post-surgery.