relationship between the underlying factors and the treatment results of platelet-rich plasma (prp) injection in degenerative knee disease; a blinded randomized study

Background: to investigate the therapeutic effects of prp injection + conservative treatment as the intervention group versus normal saline injection + conservative treatment as the control group. objectives: this study we determined the effects of underlying factors, including age, gender, and body mass index (bmi), on the therapeutic effects of prp. methods: in this single-blinded randomized clinical trial, 60 patients with grade 2 knee oa with an age of 40 - 65 years were enrolled. in the intervention group, leukocyte-poor prp with double spinning, and in the control group, normal saline was injected with a similar protocol. all patients in both groups were also provided with a conservative protocol, including oral celecoxib 100 mg bid for four weeks, modifying physical activity, and 15 sessions of physiotherapy. results: demographic characteristics (age, gender, and bmi) and pre-treatment scores were similar between the two groups (all p > 0.05). the womac score was improved from pre-treatment to first week post-treatment in both groups (from 54.89 ± 3.4 to 64.9 ± 3.7 in the intervention group and from 53.7 ± 3.1 to 63.8 ± 3.9 in the control group). it means that prp + conservative treatment was effective, similar to normal saline + conservative treatment. after adjusting bmi as an underlying variable, it was indicated that in the patients with lower bmi, prp + conservative provided a better outcome in comparison to saline + conservative treatment (p = 0.014 and p = 0.019, respectively). also, the comparison of functional scores changes with age as an underlying variable, demonstrating that younger cases obtained a better response from prp + conservative rather than normal saline + conservative (p = 0.012 and p = 0.007, respectively). conclusions: prp seems to be an appropriate choice for treatment of moderate osteoarthritis, especially in younger patients and those with lower bmi.