Are there any devices to assist/help relieve pain in the knees due to arthritis?

Try supplements. Tho' they take longer to work (up to 2 months) than rx or otc medications, try same (need to take b-complex with this) or glucosamine. Same (not if bipolar or with prostate cancer) start 400 mdg day up to 1600 mg. Glucosamine 500 mg 3x/ day. Also capsaicin cream can help. Anti-inflammatory diet (find online) will help long term as can osteopathic manipulation (better alignment) and phys therapy.
Arthritis device. There are offloader braces and braces that include electric stimulation for pain control.