Impact of Chronic Ankle Instability Following Ankle Sprain on Ankle Dorsiflexion, Heel Lift Function, and Quality of Life

Background: Chronic ankle instability (CAI) post-sprain leads to persistent functional deficits. This study evaluated CAI’s specific impact on ankle dorsiflexion, heel lift function, stability, broader functional impairments, and quality of life. Methods: A case–control study enrolled 100 CAI patients (post-ankle sprain) and 100 healthy controls. Ankle strength (isokinetic dynamometer), stability (pressure plate), maximum dorsiflexion/plantar flexion ROM (mobility meter), functional limitations (0–10 activity scale), pain (VAS), coordination (Agility T-test, figure-of-eight test), and quality of life (FAOS) were compared. ANOVA and Mann–Whitney U tests were used. Results: Compared to controls, the CAI group showed significantly reduced ankle dorsiflexion strength (114.53 ± 10.47 N vs. 156.34 ± 13.26 N), heel lift strength (78.69 ± 5.44 N vs. 105.45 ± 8.28 N), stability scores (4.73 ± 0.52 vs. 8.65 ± 0.71 points), and ROM (dorsiflexion: 16.49° ± 1.23° vs. 22.35° ± 1.65°; plantar flexion: 27.58° ± 6.51° vs. 43.27° ± 5.45°). CAI patients reported higher activity limitation (6.34 ± 1.25 vs. 2.16 ± 0.55) and pain (5.37 ± 1.02 vs. 0.23 ± 0.01) and prolonged Agility T-test (11.24 ± 1.37 s vs. 7.51 ± 1.16 s) and figure-of-eight (16.35 ± 1.67 s vs. 12.43 ± 1.39 s) times. FAOS subscale scores (symptoms, daily activities, sports, pain) were significantly lower in the CAI group. All p < 0.05. Conclusions: CAI significantly compromises ankle dorsiflexion, heel lift strength, stability, and functional mobility, correlating with increased pain, activity restriction, and diminished quality of life. Rehabilitation should prioritize neuromuscular re-education, strength restoration, and dynamic stability training to improve outcomes.