The most difficult and frightening question for orthopedic patients is: Will the nail break during the surgery? Should the nail be removed or not? When should they be removed? Will the nail rust and rot inside if it is not removed? What are the surgical procedures that require nailing in joint surgery? A: Common surgeries include periacetabular osteotomy, femoral osteotomy, hip surgical dislocation, knee osteotomy orthopedic surgery, joint fusion, etc. All of these surgeries require nailing. Why is nailing necessary? A: Orthopedic surgery requires internal fixation materials such as nails to connect the disconnected bones so that the bones can grow and heal. How are these nails made? A: The method of nailing is different for each surgery. In the case of periacetabular osteotomy, in order to put the crooked hat of the acetabulum on the “head” of the femur, we need to completely cut off the acetabulum from the pelvis and rotate it (hence the name periacetabular osteotomy) to the normal position where the hat is put on. The position of the cap is normal. Therefore, the fixation is very much a “candy cane”, which requires the use of 4 nails crossed to reposition the acetabulum to the pelvis in the correct position for wearing the cap. Q: Do I need to remove the nails that are pinned into the bone? Yes. The reasons why the nail must be removed from the bone are: 1. The nail is after all a metal foreign body that is nailed to the bone and is a double-edged sword. On the one hand, it can play the role of internal fixation of holding support solid; on the other hand, it will deprive the bone of its own “anchor” force, so that the support and strength of the bone becomes fragile because of the unexpected intervention of the nail. 2, if the patient’s nail is not removed, it may seriously affect other surgeries that need to be done afterwards. For example, patients with periacetabular osteotomy may face artificial hip replacement decades later. If the nail is not removed, it may affect the total hip replacement when grinding and frustrating the acetabulum, the acetabulum is nailed, it will not be able to grind and frustrating, just like encountering the steel in the concrete wall, so that the operation encountered obstacles, can not be done down the road. At this point, the nail can only be removed first, and then the total hip replacement can be done. When exactly should the nail be removed? A: At 3 months, 6 months and 12 months after surgery, we ask the patient to come to the hospital for a review and decide when to remove the nail according to the different recovery status of each patient. The general principle of nail removal is that as long as the doctor judges that the bone has grown solidly, it can be removed. For example, for patients with 4 nails in periacetabular osteotomy, nails can be removed under local anesthesia as soon as one year after surgery. For patients with femoral osteotomy, the fixed plate of the thigh bone usually takes 1.5 to 2 years to be taken out, which requires inpatient lumbar or general anesthesia.