This is a single-center, prospective, randomized, single-blind, comparator therapy, parallel group study for symptomatic patients diagnosed with knee osteoarthritis. The aim is to demonstrate superior efficacy of platelet-rich plasma (PRP) as compared to hyaluronic acid (HA) in treating knee osteoarthritis. This aim will be objectively measured by endpoint consisting of changes in cartilage thickness from baseline in the MRI. The Knee Injury and Osteoarthritis Outcome Score (KOOS) Questionnaire will be used to calculate The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score. It will measure changes in pain and function from baseline. Approximately 100 subjects will be treated at NorthShore University HealthSystem (NorthShore) as part of this study. This study has the potential to improve outcomes in a very common chronic degenerative disease, osteoarthritis, which can have a significant effect on individuals' quality of life.

This is a prospective, randomized, single-blind, comparative clinical trial with an allocation ratio of 1:1. The primary endpoint is the MRI-based cartilage thickness measurement. The secondary endpoint is the The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score. There are 2 arms: PRP treatment and HA treatment. Due to the treatment procedure, the study will not be blinded to either the subject or PI. However, the radiologist that scores the cartilage thickness will be blinded with regard to clinical characteristics and treatment of subjects.

The subjects are randomized with 1:1 block randomization with a block size of 4 patients. The patient population is symptomatic patients diagnosed with knee osteoarthritis K-L grade 2 or 3. The sample size is 100 total subjects (50 in each arm). The duration is approximately 13 months, final data accumulated at month 12 after treatment at single site - NorthShore.

All potential subjects will complete screening blood work which will consist of a complete blood count to include platelets and differential (CBC with Diff), c-reactive protein (CRP), and a sed rate (ESR).

Patients randomized into the PRP group will also have at the time of the procedure whole blood and PRP analyzed for PLT, WBC, and RBC per injection, and a CBC with leukocyte differential will be performed on the PRP to evaluate the fold increase in platelet concentrations. The amount of blood taken for the procedure will be approximately 15 ml (3-4 teaspoons). Four to six milliliters are injected back into the knee as plasma rich platelets.

Patients randomized to the HA group will not undergo any laboratory testing.

Data will be summarized as mean±sd for continuous variables and frequencies and percentages for categorical variables. For the primary analysis, repeated measures ANOVA will be performed on both primary and secondary endpoints using baseline and 12 months data to examine the differences in changes between PRP and HA groups. In addition, linear mixed models will be used to analyze WOMAC scores (baseline, 1m, 3m, 6m, and 12m) and MRI data (baseline, 6m, 12m) using all available data collected from all time points. All analysis will be performed with SAS 9.3 (SAS Inc., Cary, NC). A p value <0.05 will be considered statistically significant.

Inclusion Criteria:

• Ability to provide informed consent
• Chronic pain (>3 months)
• Grade 2 -3 according to Kellgren- Lawrence (K-L) classification system (using bilateral anteroposterior radiograph image acquired while the patient is weight-bearing with both knees in full extension)
• Minimum score of 40 out of possible 100 on the VAS (Visual Analog Scale) for pain
• Age 18 to 75 years old
• Physical exam and medical history
• Complete Blood Count to include platelets and differential (CBC with Diff) within normal limits
• C-Reactive Protein (CRP) within normal limits
• Sed Rate (ESR) within normal limits
• Survey of current medications

Exclusion Criteria:

• Presence of major axial deformity (>5° valgus or varus deviation)
• Surgery on target knee within 12 months prior to scheduled treatment
• Autoimmune disorder
• Active infections
• Immuno-suppression (e.g., AIDS, etc.)
• Anti-coagulant therapy
• Use of NSAIDs 5 days prior to blood draw or up to 7 days after last PRP / HA treatment
• Hemoglobin (Hg) <12 g/dL
• Platelet counts (PLT) <150,000 /mm3
• Previous infiltrative treatment within 3 weeks prior to scheduled treatment
• Pregnancy/Breastfeeding
• Hypersensitivity to HA
• Inability to complete an MRI due to metal implants or claustrophobia
• Diabetes
• Active treatment for a malignancy
• Active wound in the knee
• Recent history of knee trauma
• Vasovagal history
• An injection of hyaluronic acid (HA) or platelet-rich plasma (PRP) to the affected knee within the last two years.
• In the judgment of the investigator, the patient is unable to perform and/or complete all of the study visits or treatments required.