Platelet-Rich Plasma for Osteoarthritis

PRP is defined as a volume of autologous plasma, derived from centrifugation of the patient’s whole blood, with a platelet concentration greater than the average in peripheral blood. PRP contains biologically active proteins, cytokines, and growth factors derived from platelets a-granules. Intra-articular PRP injection may reduce pain and inflammation as well as influence joint homeostasis promoting both the healing process and immunoregulation. It is cost-effective and convenient for patients. It is a safe treatment which very rarely leads to mild local complications, which are transient; it is easy to prepare and administer, and it is less invasive compared to other orthobiologics such as bone marrow or adipose tissue-derived products. There is a plethora of randomized controlled trials and meta-analyses documenting superior results for PRP compared to placebo, corticosteroids, and hyaluronic acid injections, in terms of pain relief, functional improvement, and lasting effect up to 12 months. There are also RCTs and meta-analyses which do not support the use of autologous PRP for the management of knee OA. The principal drawback of the relevant literature is the high heterogeneity and lack of standardization in terms of PRP preparation and content. While leukocyte poor PRP has been suggested to be preferable to leukocyte-rich PRP for the treatment of knee OA, the literature is still inconclusive on this matter. PRP is more effective in younger patients with mild to moderate knee OA. Whether PRP can affect OA progression is yet to be confirmed in clinical studies, although 68% of relevant animal studies showed disease-modifying effect.