Comparative effectiveness of prolotherapy and platelet-rich plasma in patients with stage II–III gonarthrosis: A randomized controlled trial

Prolotherapy and platelet-rich plasma in patients with gonarthrosis

Abstract

Background/Aim: Gonarthrosis (knee osteoarthritis) is a common degenerative musculoskeletal condition that causes progressive joint pain, stiffness, and functional impairment. Conservative nonsurgical treatments primarily provide symptomatic relief, whereas regenerative orthobiologic interventions, including platelet-rich plasma (PRP) and hyperosmolar dextrose prolotherapy, have attracted interest because of their potential therapeutic effects. This study compared the clinical effectiveness of PRP and dextrose prolotherapy in patients with stage II–III gonarthrosis.

Methods: In this prospective, randomized, assessor-blinded controlled trial, 105 patients aged 40–70 years with Kellgren–Lawrence grade II–III gonarthrosis were enrolled between November 2020 and April 2021 and followed through October 2021. Participants received three intra-articular injections of either 25% dextrose prolotherapy (n = 52; 6 mL) or leukocyte-poor PRP (n = 53; 3 mL; estimated 4- to 5-fold baseline platelet concentration) at 3-week intervals. Both groups performed a standardized daily quadriceps-strengthening program. The prespecified primary outcome was the Visual Analog Scale (VAS) walking-pain score at 6 months. Secondary outcomes were the Lysholm Knee Score and active knee-flexion range of motion (ROM), assessed at baseline and at 3 and 6 months. Data were analyzed using linear mixed-effects models with 95% confidence intervals (CIs) and exact P-values.

Results: All 105 randomized participants completed the protocol. Both groups showed significant improvements in pain and function from baseline to 6 months (P < 0.001). At 6 months, PRP produced greater improvement than prolotherapy in the VAS pain score (adjusted mean difference, 0.42 cm; 95% CI, 0.08–0.76; P = 0.015; group-by-time interaction, P = 0.018), Lysholm score (adjusted mean difference, 7.64 points; 95% CI, 0.32–14.96; P = 0.041; interaction, P = 0.024), and knee-flexion ROM (adjusted mean difference, 3.68°; 95% CI, 0.51–6.85; P = 0.006). No serious adverse events occurred. Transient postinjection soreness occurred in 15.3% of prolotherapy recipients and 18.8% of PRP recipients (P = 0.640).

Conclusion: Both leukocyte-poor PRP and 25% dextrose prolotherapy were safe and effective nonsurgical treatments for early- to moderate-stage knee osteoarthritis. PRP provided statistically greater improvements in pain, function, and mobility at 6 months; however, the between-group differences were modest and should be interpreted in relation to clinically important thresholds.