For patients who have had only one side of their hip replaced, they often wonder if they can sleep on their side after the joint is replaced. Will sleeping on your side “crush” the new hip joint? In fact, patients can sleep without any worries one to two days after the surgery, not necessarily six weeks or three months after the surgery. The body has natural “protective measures” such as muscles and synovial fluid around the joint, which protect the joint at all times. In addition, hip replacement surgery should be fixed very firmly during the operation. If the hip is not fixed properly, it can go wrong even if you do not press on the joint. On the other hand, if the hip joint is firmly fixed, it is very unlikely that you will have any problems with it even if you press on it. It is important to know that after hip replacement, the artificial joint will be used for 20-30 years or even longer, so it is impossible for the doctor to let the joint get loose after a sleep. However, it is worth noting that within six weeks after the artificial hip replacement, if the patient sleeps on his or her side, he or she must add a pillow between his or her legs if the affected side is on top, so that the two legs do not come together; while the affected side is on the bottom, instead of adding a pillow, he or she can sleep without any worries. So, what is the use of adding a pillow? First of all, when doing hip dislocation correction surgery, the doctor will put the patient in a side sleeping position, with the affected side on top, and inwardly tuck the affected side to bring the two legs together, and then take the hip joint out. Although the chances are very small and most patients have no problems after sleeping this way, it is still recommended to add a pillow between the two legs within six weeks after the surgery and when the affected side is sleeping on top, so that the legs are not together and the hip joint will be more stable. After six weeks, the joint capsule will have grown stronger and you will not need these auxiliary protections.