Dextrose Prolotherapy Injection Improves Dynamic Postural Balance and Reduces Risk of Recurrent Sprains in Chronic Ankle Instability: A 1-Year Randomized Placebo-Controlled Trial

To investigate whether dextrose prolotherapy (DPT) injections to the anterior talofibular ligament improve chronic ankle instability (CAI). A 52-week, 2-arm, parallel, superiority, triple-blinded randomized controlled trial. The study was performed at a university-affiliated primary care clinic. A total of 114 participants (N=114) with CAI were randomly assigned to DPT and normal saline (NS) groups in a 1:1 ratio. The DPT group and the NS group, respectively, received 5 mL of 15% dextrose (D15) and 5 mL of NS injection to the anterior talofibular ligament on weeks 0, 4, 8, and 16. The primary outcome was the Cumberland Ankle Instability Tool (0-30 points) at 52 weeks. Secondary outcomes included the Star Excursion Balance Test (SEBT), number of ankle re-sprains, health-related quality of life (measured by EuroQol 5-dimension questionnaire), and treatment satisfaction. All outcomes were assessed at baseline, 16, 26, and 52 weeks. Randomization produced 2 groups of 57 participants, (57% women; 49.9±14.8y). Although no statistically significant between-group difference was detected for Cumberland Ankle Instability Tool, DPT participants demonstrated a statistically significant improvement in SEBT compared with NS, with a difference-in-difference estimate of 4.46 points (CI, 0.51-8.41; P=.027) at 26 weeks, and 4.27 points (95% CI, 0.26-8.29; P=.037) at 52 weeks. Participants in the DPT group had a lower risk of re-sprains (adjusted odds ratio, 2.88; 95% CI, 1.21-6.89; P=.017). No procedure-related adverse events were reported. DPT is superior to NS injections in improving postural dynamic balance at 26 and 52 weeks, and experienced fewer re-sprains at 52 weeks.