When your knees are achy and stiff from osteoarthritis, you have more treatment options than you might realize. Along with pain relievers, injections and physical therapy, you can also try using a knee brace or foot insole. These assistive devices are helpful for some people with knee osteoarthritis. Knee braces are made from a combination of plastic, metal, foam and other materials. They reposition your knee to lighten the load on the damaged joint.