My strap helps me completely with my condition, which seems to be tendonitis around the Metacarpophalangeal (MP) Joint (where thumb joins the palm). It helps enough that the condition is slowly healing. Since it was caused by excessive downward force, the strap relieves the cause.
Like I said above, I prefer my homemade strap with a section of elastic, and an open hook. The elastic make it feel more natural, taking about half the weight. It also helps keep the simple open hook from falling out.
Both of my hands hurt constantly in every joint - definitely osteoarthritis. I've had more steroid shots in many joints than I can count. Just today, I started using Voltaren on my hands, and the first application helped a little. I've tried many supplements without much success, even the ones that my hand Dr. Recommended didn't make much difference. Another clarinetist on The Clarinet Transformation Community mentioned Voltaren so I'm trying it. So far, so good, but they claim it takes a week to see Substantial improvement.
If I hadn't already bought the Ton Kooiman rests, I'd try a strap. But, I love gadgets and cool tools, so I reckon I'll win the race to see which guy dies with the most tools! 😁😁😆