A total hip replacement is a surgical procedure whereby the diseased cartilage and bone of the hip joint is surgically replaced with artificial materials. The normal hip joint is a ball and socket joint. The socket is a "cup-shaped" component of the pelvis called the acetabulum. The ball is the head of the thighbone (femur). Total hip joint replacement involves surgical removal of the diseased ball and socket and replacing them with a metal (or ceramic) ball and stem inserted into the femur bone and an artificial plastic (or ceramic) cup socket. The metallic artificial ball and stem are referred to as the "femoral prosthesis" and the plastic cup socket is the "acetabular prosthesis." Upon inserting the prosthesis into the central core of the femur, it is fixed with a bony cement called methylmethacrylate. Alternatively, a "cementless" prosthesis is used that has microscopic pores which allow bony ingrowth from the normal femur into the prosthesis stem. This "cementless" hip is felt to have a longer duration and is considered especially for younger patients. Total hip replacement is also referred to as total hip arthroplasty.
Total hip replacements are performed most commonly because of progressively worsening of severe arthritis in the hip joint. The most common type of arthritis leading to total hip replacement is degenerative arthritis (osteoarthritis) of the hip joint. This type of arthritis is generally seen with aging, congenital abnormality of the hip joint, or prior trauma to the hip joint. Other conditions leading to total hip replacement include bony fractures of the hip joint, rheumatoid arthritis, and death (aseptic necrosis, or avascular necrosis) of the hip bone. Hip bone necrosis can be caused by fracture of the hip, drugs (such as chronic use of prednisone and prednisolone), alcoholism, and systemic diseases (such as systemic lupus erythematosus).
The risks of total hip replacement include blood clots in the lower extremities that can travel to the lungs (pulmonary embolism). Severe cases of pulmonary embolism are rare but can cause respiratory failure and death. Other problems include difficulty with urination, local skin or joint infection, fracture of the bone during and after surgery, scarring, limitation of motion of the hip, dislocation of the hip replacement, and loosening of the prosthesis that eventually leads to prosthesis failure. Because total hip joint replacement requires anesthesia, the usual risks of anesthesia apply and include heart arrhythmias, stroke, liver toxicity, and pneumonia.
The preoperative evaluation generally includes a review of all medications being taken by the patient. Anti- inflammatory medications, including aspirin, are often discontinued one week prior to surgery because of the effect of these medications on platelet function and blood clotting. Other preoperative evaluations include complete blood counts, electrolytes (potassium, sodium, chloride), blood tests for kidney and liver functions, urinalysis, chest X-ray, EKG, and a physical examination. Your physician will determine which of these tests are required, based on your age and medical conditions. Any indications of infection, severe heart or lung disease, or active metabolic disturbances such as uncontrolled diabetes may postpone or defer total hip joint surgery
A total hip joint replacement takes approximately two to four hours of surgical time. The preparation prior to surgery may take up additional time. After surgery, the patient is taken to a recovery room for immediate observation that generally lasts between one to four hours. The lower extremities will be closely observed for both adequate sensation and circulation. If unusual symptoms of numbness or tingling are noted by the patient, recovery room nurses are available and should be notified by the patient. Upon stabilization, the patient is transferred to a hospital room.
During the immediate recovery period, patients are given intravenous fluids. Intravenous fluids are important to maintain a patient's electrolytes and replace any fluids lost during surgery. Using the same IV, antibiotics might be administered as well as pain medication. Patients also will notice tubes draining fluid from the surgical wound site. The amount and character of the drainage is important to the doctor and can be monitored closely by the nurse in attendance. A dressing is applied in the operating room and will remain in place for two to four days to be later changed by the attending surgeon and staff.