The following cases need to be fixed in a cast: 1. The most common is the stability fracture of various parts. When a fracture is produced, if the alignment of the fracture end is good and the fracture end is relatively stable, there is no need for surgical treatment and only a cast is needed as external fixation. If the fracture position is not good and unstable, it cannot be put in a cast and needs to be treated surgically.2. When a tendon is ruptured, it needs to be fixed in a cast, which is needed for conservative treatment of tendon rupture and for fixation after tendon rupture surgery, and the time for fixation in a cast is about 4 weeks.3. After nerve rupture suture and vascular rupture suture, it also needs to be fixed in a cast, and the time for fixation in a cast is 2-3 weeks.