Knee pain is the most common peripheral joint to bring patients into the clinic. The economic and social impacts of knee pain related to osteoarthritis are profound. Symptoms include pain when standing or walking, swelling, stiffness, weakness, instability, popping or crunching noises, and an inability to fully straighten the knee. Many patients discover that they have flare-ups which pass with home treatments and rest — but over time, these conditions may get worse and become more constant.