A Study of the Safety and Efficacy of Hylan G-F 20 (Synvisc) in Patients With Symptomatic Osteoarthritis of the Knee

Inclusion Criteria: * Patient with documented diagnosis of primary osteoarthritis (OA) of the target knee made at least 3 months prior to Screening, * Has radiographic evidence of OA in the tibio-femoral compartment of the target, knee with at least 1 definite osteophyte and a measureable joint space, as diagnosed by standard X-rays taken not longer than 3 months prior to Screening, and before any baseline assessment, * Has continued target knee pain despite conservative treatment (e.g. weight reduction, physical therapy, analgesics), * Has pain in the target knee as demonstrated by a score of 2 or 3 on the Western Ontario and McMaster Universities Osteoarthritis Index Likert Scale Version 3.1 (WOMAC LK 3.1) A1 (Walking Pain) Subscale , * Has a mean score of 1.5 to 3.5 on the Western Ontario and McMaster Universities Osteoarthritis Index Likert Scale Version 3.1 (WOMAC LK 3.1) A (Pain) Subscale. * Inclusion Criteria for Repeat Phase: Must have no major safety concerns during the first course of treatment as assessed by the Investigator; Must have a WOMAC LK 3.1 A score of at least 1. Exclusion criteria: * Has modified Kellgren-Lawrence Numerical Grading System of grade IV in the patello-femoral compartment of the target knee confirmed by standard X-rays taken not longer than 3 months prior to Screening, and before any baseline assessment, * Has clinically apparent tense effusion of the target knee, * Has had viscosupplementation in any joint including the target knee within 9 months prior to Screening, * Has concomitant inflammatory disease or other condition that affects the joints (e.g. rheumatoid arthritis, metabolic bone disease, psoriasis, gout, symptomatic chondrocalcinosis and active infection, etc.,) * Symptomatic OA of the contralateral knee or of either hip that is not responsive to paracetamol and requires other therapy, * Has related hypersensitivities to avian proteins and/or any components of hyaluronan-based injection devices,