Acute effects of posterior tibial nerve percutaneous neuromodulation on postural control in individuals with chronic ankle instability

Background Chronic ankle instability (CAI) affects approximately 46% of individuals after ankle sprains, disrupting ligaments, muscles, and joint receptors, and impairing postural control. Percutaneous tibial nerve stimulation (PTNS) is a minimally invasive neuromodulation technique that may enhance neuromuscular function. This study aimed to evaluate the acute effects of ultrasound-guided PTNS on postural control in individuals with CAI compared to healthy controls. Methods This non-randomized controlled study included 28 participants: 14 with CAI (mean age 22.85 ± 5.02 years; BMI 24.83 ± 4.28) and 14 healthy controls (mean age 21.86 ± 3.44 years; BMI 22.8 ± 3.29). CAI diagnosis was confirmed by scores <24 on the Spanish Cumberland Ankle Instability Tool. Postural control was assessed via force platform during single-leg stance with eyes open and closed at baseline, immediately post-intervention, and at 2, 24, and 48 h post-PTNS. PTNS delivered biphasic current (10 Hz, 250 µs pulse width) at maximum tolerable intensity for 1.5 min under ultrasound guidance. Controls received no intervention. Results Baseline postural control did not differ significantly between groups ( p > 0.05). Post-PTNS, no significant intergroup differences were observed, except a reduction over time in anteroposterior center of pressure amplitude (ACPap) in the CAI group with eyes closed ( p = 0.023). No significant intragroup changes occurred. Conclusions Although PTNS did not produce general improvements in postural control, the reduction in anteroposterior sway with eyes closed suggests a targeted neuromodulatory effect. These preliminary results support further research into PTNS as a complementary approach for managing CAI. Trial registration: ISRCTN177653522