Non-Inferiority Study Comparing 3 Weekly Injections of SUPARTZ® vs 3 Weekly Injections of Euflexxa® for Knee OA

Inclusion Criteria: * Clinical evidence of symptomatic osteoarthritis of the study knee as classified according to Altman criteria. * Symptoms in study knee for at least one year prior to the screening visit * Verified OA of the study knee of Grade 2 or 3 according to a modification of the grading system of Kellgren-Lawrence (K-L) radiographic severity. * Willingness to discontinue NSAIDs (systemic and topical) and non-acetaminophen analgesic use seven days or five half-lives prior to the first injection and throughout the study. Exclusion Criteria: * Inability to perform a 50 foot walk test. * Subjects with rheumatoid arthritis, joint infection, other inflammatory and metabolic arthritis, Lupus or dermatologic disorder or skin conditions in close proximity to study knee that would preclude safe intra-articular injections. * Prior hyaluronic acid injections into the study knee within six months of the screening visit. * Intra-articular or intra-muscular steroid injections within three months of the screening visit or during study participation. Oral corticosteroids within four weeks of the screening visit or during study participation. * History of surgical treatment to the study knee or arthroscopic intervention within three months prior to the screening visit. * Clinically apparent tense effusion of the study knee on examination determined by either a positive bulge sign or positive ballottement of the patella (patellar tap). * Subjects with clinically diagnosed symptomatic OA of the hip.