A Study to Assess Safety and Tolerability of PCRX-201 in Subjects With Painful Osteoarthritis of the Knee

The goal of this clinical trial is to learn if a single knee injection of different doses (Dose A and Dose B) of an investigation product PCRX-201, following steroid pretreatment, is safe and tolerable in male of female patients 45 to 80 years old with osteoarthritis of the knee. It will also learn how the body reacts to the PCRX-201 injection and how effective the treatment is. Researchers will compare Dose A and Dose B of PCRX-201 versus placebo from Week 1 through Week 52 to assess adverse events. Researchers will also explore how PCRX-201 may impact knee pain and joint function over time. Participants will be asked to * Visit the clinic for pretreatment and drug administration * Visit the clinic for checkups and tests: 1. Screening through Week 52: intially weekly, bi-weekly, later monthly 2. Week 53 through Week 260 (Year 5): 8 visits throughout the period