osteoarthritis grade 2 or 3 in one knee using kellgren-lawrence grading for oa radiologically and verified within the prior 6 months.

secondary oa resulting from rheumatoid arthritis, chondrocalcinosis, osteonecrosis, chronic fibromyalgia or other autoimmune disease.

generalized symptomatic oa in lower extremity joints other than the knees.

active infection in either knee joint or adjacent tissues.

any contraindications for intra-articular injection or aspiration.

knee surgery or trauma within 3 months prior to enrollment.

intra-articular steroid injection in the knee and/or use of systemic (oral) corticosteroids within 3 months prior to enrollment.

intra-articular hyaluronan injection in the treatment knee within 6 months prior to enrollment.

body mass index (bmi) greater than 35.