The elbow is not straight after the injury because after the elbow injury, there will be significant swelling and bruising in the soft tissues, and the muscles and ligaments will be damaged to varying degrees, so it will cause the joint to not straighten. If the fracture line involves the joint or there is damage to the articular cartilage, it will also cause the elbow joint to be unstraight and requires timely surgical anatomical repositioning so that it will not be affected when it recovers in the future. There is also a long period of inactivity of the elbow joint after the fracture, so the local muscles and ligaments are stiff and the joint cannot be straightened. The timing and specific time of rehabilitation exercises should be done under the guidance of a doctor to avoid the damage caused by premature exercise, and the time and magnitude of each exercise should not be too large, but should be done gradually.