50 Subjects between 21-80 years with a BMI \< 40 with mild to moderate knee osteoarthritis on x ray (KL grade II or III) will have a ultrasound guided arthrocentesis with an external pneumatic compression device (KneeTap) and if \> 0.5 ml of synovial fluid is obtained they will received the first of 2 FDA approved Hymovis knee injections. A second ultrasound guided Hymovis intra-synovial space injection will be administered in one week with a repeat arthrocentesis in 3 months. Subjects will be compensated $ 50 for each of 4 of 5 study visits. Clinical outcome measures at study visits 1, 3 (3 months) 4 at (6 months) and 5 (12 months will include: VAS (Visual analog Global pain (1-10), SF -36 ,WOMAC questionnaires (Western Ontario and McMaster University Arthritis Index pain Scale), measured distance on 6 minute walking distance test and synovial fluid depth measured by ultrasound. The Synovial fluid biomarker panel will include values of over 45 separate cytokines,.chemokines and proteins from subjects pre vs post Hymovis injections and compared to values in the peripheral blood obtained simultaneously. SF biomarker analysis will be performed on cryopreserved samples using fluorescence multiplex bead based assays (Luminex) or by ELISA. All values as well as clinical outcome parameters will be entered into the REDCap system for statistical analysis
