Platelet Rich Plasma Injection for Knee Osteoarthritis

Overview

The research questions of this study are; 1. Is platelet rich plasma (PRP) treatment effective in knee osteoarthritis (OA)? 2. What are the indications for PRP treatment? 3. Which patients are the most suitable for the PRP treatment method? 4. How does age, Body Mass Index (BMI), lower extremity mechanical axis angle and OA stages affect the success of the PRP treatment? 5. Is there any advantage of multiple PRP doses? 6. What is the therapeutic effect of placebo? This study was designed to find answers of these questions. The hypotheses of this study are; "PRP treatment is more effective than placebo; PRP treatment effectiveness decreases with age and advanced stages of OA; BMI is a factor that negatively affects the treatment effectiveness of the PRP; as the mechanical axis angle of the lower limb increases, it will adversely affect the effectiveness of PRP therapy; multiple dose of PRP affects the effectiveness and duration of PRP as positively compared to single dose of PRP". The primary purpose of this study; to prove the effectiveness of PRP treatment on knee pain and functions in patients with knee OA by comparing it with the placebo control group. Secondary purposes of this study; to understand the effect of age, BMI, OA grade and lower limb mechanical axis angle on PRP effectiveness. This study, designed as a randomized, double-blind and placebo control group, with a high level of scientific evidence. Thus, it will be scientifically possible to find answers to the investigators research questions and to prove the investigators hypothesis.

The power analysis of this study was calculated based on the sample size studies of previous studies. The difference of d = 3 units between the two means is to have a standard deviation of 6 units. The sample size 200 required to detect with 95% power in the 95% confidence interval to detect. This study covers 324 patients. All patients were selected according to predefined and established inclusion and exclusion criteria. Inclusion criteria were: stage 1-2-3 symptomatic OA patients according to Kellgren / Lawrence staging, age between 18 and 80 years, mean Visual Analogue Score (VAS) of \>4 of 10 (worst possible pain) over the course of 7 days during the previous month were included on a voluntary basis. Only one knee injection was made to the patients. Exclusion criteria were OA secondary to joint inflammatory diseases; patients with generalized OA, metabolic diseases of the bone, coexisting backache, the presence of hematological disease (coagulopathy), bilateral symptomatic lesions and advanced stages (grade 4) of OA; patients who had received intra-articular injections within three months or arthroscopic lavage in the previous one year or who were receiving immunosuppressive; patients with current use of anticoagulant medications or NSAIDs used in the five days before blood donation, major axis deviation (more than 15 degree of varus or more than 5 degree of valgus deviation); and patients with a hemoglobin level less than 11.5 g/dL and platelets level less than 100,000/μL or associated co-morbidities, infection, tumor, crystal arthropathies, anemia, tense joint effusion and pregnancy or possibility of pregnancy. The voluntary patients included in this study were divided into four different groups with a computer-assisted randomization program. This groups; group A (n:67) were given a single injection of PRP, group B (n:69) were given a single injection of normal saline (physiological control/placebo), group C (n:66) were given three injection (one per month) of PRP, group D (n:65) were given three injection of normal saline (one per month) (physiological control/placebo). All patients were evaluated by a blinded researcher with VAS, Knee injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), KUJALA, knee range of motion (ROM) and knee circumference measurement at 1st, 3rd, 6th, 12th and 24th months after treatment.