A friend gave me an elastic knit sleeve to wear backpacking, but can’t say whether it helped.
What did help was annual injections of compounds containing hyaluronic acid into the knee compartments using ultrasound. These were brand named ‘Orthovisc’, ‘Synvisc’, and other names, done with three injections, a week apart. They were very helpful. Also tried ‘PRP’, meaning ‘Plasma Rich Platelets’, injected into the knee; but again am not sure if that was helpful. And it was not covered by my insurance, so was expensive.
A friend also recommended ‘Doc Sleeves,’ that she said are very helpful. They are sold on Amazon, and appear to be a hybrid between an elastic and a mechanical sleeve.
I did try the Cho-Pat years ago, and it did not help.
What also does help are exercises: Hip Abductions (Jane Fonda’s), increasing the hold times; and Donkey Kicks, also increasing the hold times, to strengthen the muscles around the knees. I cannot do leg raises lying on my back, often recommended, due to back issues.