Dr. Akpancar and colleagues reported a study in 2019, with reference listed below.  They compared 3 injection sessions at 3-week intervals of either platelet rich plasma (PRP) or 25% dextrose (dextrose prolotherapy/DPT). TParticipants had chronic ankle pain resistant to 3 months of standard treatment and proven ankle arthritis by plain X-rays. 56 participants were included, half in each group, with alternate (not computer based) assignment to either treatment.  However, dropout was more in the platelet rich plasma group, so that data was available for analysis at one year on 22 PRP and 29 DPT recipients. Marked improvements occurred in standard ankle arthritis pain measures, with no significant difference between groups at one year. The authors comment that  DPT was more cost-effective.  This study's weaknesses were lack of true randomization, absence of blinding, and more dropout in the PRP group.  Its strength was a long period of follow-up.   Despite several areas of bias that would favor PRP over DPT, the DPT recipients did just as well.  Because this is a treatment comparison study, the Strength of Recommendation (SOR) rating of this study for efficacy of dextrose injection would be B-. (Sufficient such that evidence-based physicians should consider referring patients for this treatment).

Akpancar S, Gül D. Comparison of Platelet Rich Plasma and Prolotherapy in the Management of Osteochondral Lesions of the Talus: A Retrospective Cohort Study. Med Sci Monit. 2019 Jul 30;25:5640-5647. doi: 10.12659/MSM.914111. PMID: 31358724; PMCID: PMC6685325.
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For more detail, the entire paper is available at https://www.medscimonit.com/download/index/idArt/914111