The comparison effects of intra-articular injection of Platelet Rich Plasma (PRP), Plasma Rich in Growth Factor (PRGF), Hyaluronic Acid (HA), and ozone in knee osteoarthritis; a one year randomized clinical trial.

Background: Our study compare the short and long-term efficacy of the intra articular injections (IAIs) of hyaluronic acid (HA), platelet-rich plasma (PRP), plasma rich in growth factors (PRGF), and ozone in patients with knee osteoarthritis (OA).

Methods: In this randomized clinical trial, 238 patients with mild to moderate knee OA were randomized into 4 groups of IAIs: HA (3 doses weekly), PRP (2 doses with 3 weeks interval), PRGF (2 doses with 3 weeks interval), and Ozone (3 doses weekly). Our outcome measures were the mean changes from baseline (immediately from the first injections) until 2,6, and 12 months post intervention in scores of visual analog scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Lequesne index.

Results: A total of 200 patients enrolled in the final analysis. The mean age of patients was 56.9 ± 6.3 years, and 69.5% were women. In 2 months follow up, significant improvement of pain, stiffness, and function were seen in all groups compared to the baseline, but the ozone group had the best results (P < 0.05). In 6 month follow up HA, PRP, and PRGF groups demonstrated better therapeutic effects in all scores in comparison with ozone (P < 0.05). At the end of the 12th month, only PRGF and PRP groups had better results versus HA and ozone groups in all scores (P < 0.05). Despite the fact that ozone showed better early results, its effects begin to wear off earlier than other products and ultimately disappear in 12 months.

Conclusions: Ozone injection had rapid effects and better short-term results after 2 months, but its therapeutic effects did not persist after 6 months and at the 6-month follow up, PRP,PRGF and HA were superior to ozone. Only patients in PRP and PRGF groups improved symptoms persisted for 12 months. Therefore, these products could be the preferable choices for long-term management.

Trial Registration: Registered in the Iranian Center of Clinical Trials ( www.irct.ir ) in 11/11/2017 with the following code: IRCT2017082013442N17.