I am 46 years old with arthritis in my knees. I have had both knees scoped and had synvisc (hylan g-f 20) in one knee to little effect. What should I do next?

Hyalgan. You could try the protocol with Hyalgan with physical therapy. Many of my patients have had real success with increased mobility and decreased pain.
Therapy. The basics for oa of the knee included weight reduction, exercises and nsaids. Deweighting the joint with a can can be helpful as well. Sometimes if using one form of viscosupplimentation doesn't work much then trying another one of them such as euflexxa may be helpful. Physical therapy and then compliance with home exercises is crucial in relieving the pain of knee arthritis.
See your PCP. Follow up with your primary care physician. There are many non-pharmacological and pharmacological treatments for knee pain due to "arthritis" depending on which type of arthritis you have. Most likely you have osteoarthritis since that is the only fda approved indication for synvisc. The best treatment for this is weight loss and exercise. Others include tylenol, (acetaminophen) nsaids and joint replacement.