RhizoLoc® stabilizing orthosis helps stabilize the thumb saddle and first metacarpophalangeal joints due to thumb joint injuries, such as tears or sprain to the collateral ligaments ("skier's thumb"), or for indications of osteoarthritis (arthrosis of first carpometacarpal joint) or irritation. It has an individually adaptable aluminum stay which stabilizes the thumb saddle and metacarpophalangeal joint allowing optimal healing of the affected collateral ligaments. A special Velcro® tab allows the mobility of the joint to be limited according to the treatment. It is comfortable and stable, easy to put on and take off and made up of a breathable material especially for skier's thumb sufferers. The Velcro tab can be adjusted in order to limit the movement of the metacarpophalangeal joint and to immobilize it as treatment requires.