A sudden blow can separate two bones at the joint, partly or entirely. The shape of the area, often in the hand or shoulder, might change, and the area might become swollen, numb, and painful. Sometimes it damages tendons, ligaments, or nerves. Your doctor may push the bones back into place. After that, rest, ice, and physical therapy can help you heal, along with medication to ease pain and swelling. You may need surgery in rare cases.