The purpose of this study is to evaluate the safety and performance of Hydros Joint Therapy (Hydros) and Hydros-TA Joint Therapy (Hydros-TA) for treatment of pain from osteoarthritis of the knee, in patients who have failed to respond adequately to conservative non-pharmacologic therapy and simple analgesics.

The objective of the study is to evaluate Hydros and Hydros-TA treated subject for reduction of osteoarthritis symptoms, compared to a commercial control, as assessed by the WOMAC Osteoarthritis Index.

The WOMAC Osteoarthritis Index is a validated assessment instrument that is self-administered and designed to subjectively elicit patient symptoms of osteoarthritis in the knee in the areas of pain, stiffness, and physical function. The WOMAC Osteoarthritis Index with its Pain Subscale has been used extensively as an effectiveness endpoint in clinical trials of viscosupplements.

Inclusion Criteria:

- Osteoarthritis grade 2 or 3 in one knee using Kellgren-Lawrence Grading for OA radiologically and verified within the prior 6 months.

Exclusion Criteria:

• 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.