Every year, thousands of Americans have their hips replaced with artificial joints. Sometimes these replacements dislocate. This means the ball-shaped bone at the top of the leg comes out of the hip socket. When this happens, another operation may be needed. This is called revision total hip arthroplasty.
Prevention starts with the selection of patients for hip replacement. Certain patients are better candidates than others. Patients with hip muscle weakness and poor mental abilities are more likely to dislocate the new joint. So are patients with drug or alcohol problems.
Proper matching of patients with replacement joints helps prevent dislocation, but this isn’t always easy. Doctors sometimes have problems fitting new joints in place during surgery. If patients have more bone loss than expected, the new joint may not be stable.
If patients can’t or won’t follow directions after surgery, the joint can dislocate. For example, patients are told to avoid certain movements of the hip for at least six weeks after hip replacement surgery. When the surgery is done from the back of the hip (called a posterior approach), patients are not to move the affected leg across the middle of the body or bend it more than 90 degrees. The hip must not be turned in (rotated) at all.
Special care must be taken before, during, and after total hip joint replacement to prevent dislocation. Doctors decide what kind of surgery and replacement joints to use. These depend on patients’ health and mental status, muscle strength, and bone structure.