Comparison of Efficacy of Intraosseous vs Intra-articular Injections of PRP for Advanced Knee OA

A prospective cohort clinical study. The matched sample will be divided into two groups. Group 1 will receive two intraosseous injections of PRP and another intra-articular injection of PRP on the same day.

Group 2 will only receive two intra-articular injections of PRP, separated by one week. One week before the PRP injection, both groups will receive an intra-articular injection of 20 mg triamcinolone hexacetonide.

The PRP is obtained from an autologous blood sample. PRP production consists of a 54 mL (PRP intra-articular) and 80 mL (PRP intraosseous) sample of venous blood from the cubital vein of the patient's upper limb, using 6 x 9 ml tubes, containing a 3.2% sodium citrate solution. The tubes will be centrifuged at 2400 rpm for 12 minutes at room temperature. It is obtained a suspended concentration of PRP that is carefully extracted using a pipette to avoid aspiration of leukocytes from the buffy coat (leukocyte-poor PRP [LP-PRP]). For group 1, it will be injected 4 mL intraosseous, and 8 mL intra-articular. Group 2 will be injected 8 ml of PRP twice (one each week). A total of 8 ml of PRP will be injected into the knee.

A hemogram will be used to analyze the blood sample and the PRP to evaluate their characteristics (concentration of red blood cells, concentration of white blood cells, concentration of platelets, and mean platelet volume); with this analysis, it will be also calculated the platelet concentration growth factor (between baseline blood sample and PRP). Besides concentration, it will also be calculated the total volume of platelets injected into the knee.

All procedures will be carried out in a laminar flow chamber (0.34 m/s) to avoid contamination. Following preparation, the PRP will be injected with the minimum time elapsed since its preparation (maximum 30 minutes).