Last updated: 11/24/2009

Hip replacement surgery involves both short- and long-term risks.

Short-term risks

The most common risks associated with hip replacement are as follows:

• Dislocation of the new prosthesis. Dislocation is most likely...
  
  to occur in the first 10–12 weeks after surgery. It is a risk because the ball and socket in the prosthesis are smaller than the parts of the natural joint, and can move out of place if the patient places the hip in certain positions. The three major rules for avoiding dislocation are: Do not cross the legs when lying, sitting, or standing; never lean forward past a 90-degree angle at the waist; do not roll the legs inward toward each other—keep the feet pointed forward or turned slightly outward.
• Deep vein thrombosis (DVT). There is some risk (about 1.5% in the United States) of a clot developing in the deep vein of the leg after hip replacement surgery because the blood supply to the leg is cut off by a tourniquet during the operation. The blood-thinning medications and TED stockings used after surgery are intended to minimize the risk of DVT.
• Infection. The risk of infection is minimized by storing autologous blood for transfusion and administering intravenous antibiotics after surgery. Infections occur in fewer than 1% of hip replacement operations.
• Injury to the nerves that govern sensation in the leg. This problem usually resolves over time.

Long-term risks

The long-term risks of hip replacement surgery include:

• Inflammation related to wear and tear on the prosthesis. Tiny particles of debris from the prosthesis can cause inflammation in the hip joint and lead eventually to dissolution and loss of bone. This condition is known as osteolysis.
• Heterotopic bone. Heterotopic bone is bone that develops in the space between the femur and the pelvis after hip replacement surgery. It can cause stiffness and pain, and may have to be removed surgically. The cause is not completely understood as of 2002 but is thought to be a reaction to the trauma of the operation. In the United States, patients are usually given indomethacin (Indocin) to prevent this process; in Germany, surgeons are using postoperative radiation treatments together with Indocin.
• Changed length of leg. Some patients find that the operated leg remains slightly longer than the other leg even after recovery. This problem does not interfere with mobility and can usually be helped by an orthotic shoe insert.
• Loosening or damage to the prosthesis itself. This development is treated with revision surgery.