How Does Platelet Dose Impact Clinical Outcomes After PRP Treatment?

Knee osteoarthritis (OA) is a chronic progressive disease affecting more than 20% of people older than 45 years. A myriad of different treatments have been proposed in the scientific literature, and current treatment options include conservative and surgical procedures in which the main objective is to relieve pain and improve function. Conservative nonsurgical interventions include weight management, physical therapy, analgesics, nonsteroidal anti-inflammatory drugs (NSAIDS), corticosteroid and hyaluronic acid injections. Although these agents have been beneficial in the short term, there is a lack of evidence that such interventions alter the progression of OA. More recently, platelet-rich plasma (PRP), a biological therapy, has become an emerging treatment option to improve the status of the joint for patients with OA. PRP is an autologous blood product that is injected into the knee joint, which contains an elevated concentration of platelets above that of whole blood. However, the optimal PRP preparation is still unknown. Studies are needed that investigate optimal platelet count and how that is related to clinical outcome. This study is designed as a double-blind randomized controlled study, where enrolled subjects are randomized to one of five treatment groups (in blocks of 10): 1. a total PRP injection dose of less than 5 billion platelets; 2. a total PRP injection dose between 5 and \<10 billion platelets; 3. a total PRP injection dose between 10 and \<20 billion platelets; 4. a total PRP injection dose of \>20 billion platelets; and 5. a saline injection control Each patient will be asked to complete a questionnaire at baseline, 6, 12, and 26 weeks. After patients have completed all the study questionnaires, the Investigators will pull the results from the blood analysis, so that blood composition levels can be correlated with any pain improvements that are felt. The purpose of the study is to establish if there is a relationship between the injection dosage a patient receives and knee pain level (based on the pain scores from the self-reported questionnaire).