Effectiveness of plasma with low concentration of platelets combined with hyaluronic acid compared with platelet rich plasma in the conservative treatment of knee osteoarthritis. A retrospective study

Abstract Background: Knee osteoarthritis (KO) is one of the most common joint diseases, often determining knee pain and reduction of mobility with impact on the overall quality of life of the patients. Intra-articular injections of different formulations of platelet rich plasma (PRP) are an increasingly common non-surgical treatment for KO. Recently, in order to combine the antinflammatory effect of platelet rich plasma and the viscosupplementation effect of hyaluronic acid, a formulation of plasma with relatively low concentration of platelets and very few leukocytes combined with hyaluronic acid (PRP+HA) has been proposed. The purpose of this study is to retrospectively compare the effectiveness of plasma with high concentration of platelets and leukocytes (L-PRP) with PRP+HA in patients with mild to moderate (Kellegren-Lawrence scale II-III grade) KO.Materials and Methods: Among the 51 patients included, 28 have been treated with L-PRP, while 23 with PRP+HA. A retrospective evaluation at baseline (T0), after 3 months (T1) and 1 year (T2) has been performed. The outcome analyzed are the Knee Society Score(KSS), the Visuo Analogic Scale (VAS) (at T0,T1 and T2) and the Knee injury and Osteoarthritis Outcome Score(KOOS) (T0 and T2).We evaluated change in mean scores within group among different time points using repeated measures ANOVA or paired t-test. Comparison between different groups of treatment has been performed using mixed ANOVA.Results: The main finding is that, although the two treatments have been both effective, PRP+HA determined significantly better functional status, pain and mobility, measured with KSS.Discussion: We observed a significant effect of the two formulations in exam in all the outcomes in analysis: both treatments were effective in improving pain, knee functional status and symptoms, and the benefits persisted after 3 and 12 months from the infiltrative therapy. Nevertheless, patients who received PRP+HA injections presented higher knee mobility and better function (measured by KSS score) after one year.Conclusions: This work compares clinical outcomes of L-PRP and PRP+HA treatment in patients with KO. Our results encourage the use of one of the two treatments in patients with mild to moderate KO. When possible, we suggest to the use of PRP+HA formulation, because it may determine better results in improving knee function and mobility.