4. Weakness in the thumb is a common sign of a sprained thumb.
The thumb is weak because the ligament and bone are injured. The ligament and bone work together to allow your thumb to move back and forth.
When your thumb is weak the best thing you can do is to rest and place it over it. Place a splint over the thumb and rest it as much as possible. The splint will keep your thumb from moving when doing other activities.
When it’s not in a splint, ice it. Ice it for 10 minutes every hour. After icing, place the splint or compress back over the thumb. It will feel uncomfortable at first with the splint or compress on, but it will help to heal your thumb sprain. Your thumb will start to gain back its mobility after letting it rest for a while. The longer you let it rest, the better.