How Does Platelet Dose Impact Clinical Outcomes After PRP Treatment?

The purpose of this study is to determine which platelet rich plasma (PRP) injection dosage provides the most improvement in a patient's knee pain level at 26 weeks post-injection.

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): a total PRP injection dose of less than 5 billion platelets; a total PRP injection dose between 5 and <10 billion platelets; a total PRP injection dose between 10 and <20 billion platelets; a total PRP injection dose of >20 billion platelets; and 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).

Patient reported outcome measure: Consists of 5 subscales, one of which is "Pain". A normalized score (100 indicating no pain and 0 indicating extreme pain) is calculated for this subscale.

Patient-reported outcome measure: The scores for each subscale are summed up, with a possible score range of 0-20 for Pain. Higher scores indicate worse pain.

The Visual Analog Scale (VAS) is a unidimensional measure of pain intensity. The scale is most commonly anchored by "no pain " (score of 0) and "pain as bad as it could be" or "worst imaginable pain" (score of 10).

Inclusion Criteria: 40-80 years of age Previous diagnosis of unilateral, primary osteoarthritis of the knee Knee pain; duration of symptoms > 4 weeks K-L grade 0-4 Exclusion Criteria: Under 40 years of age; over 80 years of age Bilateral knee pain Duration of symptoms < 4 weeks NSAID or clopidogrel use in the last 7 days High risk of a thrombotic event if discontinuing NSAID or clopidogrel for four weeks. Steroid use in the last 6 weeks Active diagnosis of leukopenia/anemia/thrombocytopenia