Typically, when an adult suffers from OA of the knee, they are presented with two choices: conservative treatments consisting of NSAID therapy and physical therapy or surgical intervention to replace the affected knee joint. There is a third avenue of treatment that has become available in recent years. This treatment modality is viscosupplementation. Viscosupplementation consists of replacing hyaluronic acid in the synovial fluid contained in the knee joint. It has been observed that the synovial fluid of OA sufferers has less hyaluronic acid (HA), and the HA that remains is of lower molecular size and concentration Replacement of the HA contained in the synovial fluid through the use of Hylan G-F 20 has been shown in clinical studies to be clinically safe, and have the ability to provide pain relief with a minimum of adverse reactions. Clinical studies concerning the use of Hylan G-F 20 have focused on safety and efficacy in regards to pain relief in those who suffer OA. To date, there have been few studies performed looking at the efficacy of Hylan G-F 20 on the kinematics and kinetics of gait. This study will provide data on the ability of Hylan G-F 20 treatment to improve the temporal-spatial parameters of gait in those who suffer OA, as well as the ability of Hylan G-F 20 to reduce joint reaction forces in the affected knee.