Efficacy of Intra-Articular Hypertonic Dextrose (Prolotherapy) for Knee Osteoarthritis: A Randomized Controlled Trial

PURPOSE To test the efficacy of intra-articular hypertonic dextrose prolotherapy (DPT) vs normal saline (NS) injection for knee osteoarthritis (KOA). METHODS A single-center, parallel-group, blinded, randomized controlled trial was conducted at a university primary care clinic in Hong Kong. Patients with KOA (n = 76) were randomly allocated (1:1) to DPT or NS groups for injections at weeks 0, 4, 8, and 16. The primary outcome was the Western Ontario McMaster University Osteoarthritis Index (WOMAC; 0-100 points) pain score. The secondary outcomes were the WOMAC composite, function and stiffness scores; objectively assessed physical function test results; visual analogue scale (VAS) for knee pain; and EuroQol-5D score. All outcomes were evaluated at baseline and at 16, 26, and 52 weeks using linear mixed model. RESULTS Randomization produced similar groups. The WOMAC pain score at 52 weeks showed a difference-in-difference estimate of −10.34 (95% CI, −19.20 to −1.49, P = 0.022) points. A similar favorable effect was shown on the difference-in-difference estimate on WOMAC function score of −9.55 (95% CI, −17.72 to −1.39, P = 0.022), WOMAC composite score of −9.65 (95% CI, −17.77 to −1.53, P = 0.020), VAS pain intensity score of −10.98 (95% CI, −21.36 to −0.61, P = 0.038), and EuroQol-5D VAS score of 8.64 (95% CI, 1.36 to 5.92, P = 0.020). No adverse events were reported. CONCLUSION Intra-articular dextrose prolotherapy injections reduced pain, improved function and quality of life in patients with KOA compared with blinded saline injections. The procedure is straightforward and safe; the adherence and satisfaction were high.