Hello and welcome,
I have OA of the base of my right thumb - (CMC/carpometacarpal ) I have had it for years and did have the cortisone injections which helped for awhile. The Hand specialist explained to me I have bone on bone and surgery was scheduled.
My surgeon was going to make a cushion to pad the space between the bones where the trapezium bone used to be. This cushion is usually also made from a tendon graft so that the base of the thumb rests on a pillow of your own body tissue, rather than on the rough surface of an arthritic bone. A cast is then placed and as the swelling goes down the cast is replace.
Long story short - I developed pneumonia several days before surgery so the procedure was cancelled.
I have not had the surgery yet and the thumb seems to be holding it's own pretty well.
Good luck with your thumb osteo.
Kindly,
Kitt