Hip replacement

            The hip joint is made up of different bones.  The femur is the long bone in your thigh.  The head of the femur (femoral head) connects to your pelvis via the hip joint.  The pelvis connects to the femoral head via the acetabulum, which is a concavity.  The hip joint is a ball and socket joint.  In a total hip replacement, the femoral head and acetabular surface are replaced with a prosthetic joint. 

Who is a candidate for a total hip replacement?

            People who suffer from severe symptoms that interfere significantly with quality of life and who have failed conservative treatments are potential candidates for total hip replacement surgery.  Conservative therapy may include medications, injections, activity modification, walking aids, acupuncture, and physical therapy.   Less invasive surgical procedures such as an osteotomy in which the joint is repositioned may sometimes be attempted instead of a total hip replacement.  People who would otherwise be candidates for total hip replacement may not be appropriate candidates if they have other medical conditions that make surgery too dangerous.

What are the different types of total hip replacement surgery?

            There are different prosthetic devices that can be used to replace the hip joint.  The primary difference is whether a cement or cementless glue is used for the procedure.  The advantage of the cemented prosthesis is that the patient can return to activities sooner after surgery.  The advantage of the cementelss procedure is that the prosthesis is ultimately stronger (because the bone grows into the prosthesis) and if the prosthesis needs to be revised later on, it is sometimes easier to revise a cementless prosthesis.  However, in a cementless procedure, the patient must limit activities for approximately 3 months after surgery.  In general, older less active patients are offered cemented procedures.  These patients are less likely to wear out the new cemented prosthesis and enjoy the quicker recovery time.  Younger more active patients are typically offered the cementless procedure.  However, every patient is different and a detailed discussion of the advantages and disadvantages of each procedure should be pursued between the patient and physician.

What are the potential risks and complications of a total hip replacement surgery?

            There are risks to any surgery, including the risk of general anesthesia.  Risks of general anesthesia are rare but include heart attack, pneumonia, stroke, liver toxicity, and death.  More than 120,000 hip replacements are performed annually in the United States alone and less than 10 percent of these require any further surgery.  The most common complication of a total hip replacement is gradual loosening of the prosthesis.  If this happens, a repeat surgery may be necessary to fix the prosthesis.  Other complications include hip dislocation after surgery.  Following surgery, patients are given hip precautions to be followed anywhere from 3 to 6 months.  Hip precautions include not bending over to tie your shoes and not crossing your legs.  When hip precautions are followed the chances of post-operative dislocation are reduced.

            Another potential complication of a total hip replacement includes a clot in your leg called a deep vein thrombosis (DVT).  When a clot develops in your leg, it can potentially travel to your lungs.  This is called a pulmonary embolus (PE). If a pulmonary embolus develops, it may compromise your ability breathe in oxygen.  A leg clot can also travel to your brain under certain circumstances and cause a stroke.  More than 50% of patients will develop a clot in their leg if their blood is not thinned with medication.  Doctors have many different medications to choose from to thin blood and help prevent against a clot.  However, these medications (including aspirin, heparin, lovenox, and/or coumadin) all have side effects and some patients are not able to take them.  If you are not a candidate for anti-coagulation, you may require a filter to be placed by your lungs to prevent potential clots from traveling to your lungs and causing compromised breathing.  It is important that you discuss these and all potential complications and prevention and treatment strategies with your physician before surgery. 

            What does the rehabilitation process involve after total hip replacement surgery, and when does it begin?

            The rehabilitation process begins as early as the first day after surgery.  Patients are reminded of their hip precautions.  As previously discussed, these include not crossing the affected leg past midline (not crossing leg over leg), not bending at the waist to tie shoes or put on socks.  Basically, the hips should not be flexed past 90 degrees.  Adaptive equipment such as a raised toilet seat is important to aid the patient in following hip precautions. 

            On the first post-operative day, patients generally begin light exercises while sitting in a raised chair.  Patients then gradually increase exercise therapy, focusing on stretching and strengthening the surrounding muscles.  Post-operative physical therapy is critical to the success of the operation and the swift return of the patient to his or her favorite activities.  Occupational therapy is also very helpful for teaching the patient how to use adaptive equipment in performing their activities of daily living once they go home.  Patients generally don’t spend more than 10-14 days in the hospital after surgery.  Once home patients continue to participate in a structured outpatient physical therapy program.  If a cemented fixation was used, the patient will most likely be encouraged to put as much weight on the affected leg as he or she can tolerate.  If, however, a cementless procedure was used, the patient will likely be instructed to put less than 20% of their body weight on the affected limb for at least 6 weeks after surgery.  At that time a radiograph would be obtained to assess for bony ingrowth prior to allowing the patient to place more weight on the limb.  This naturally slows the rehabilitation process.  However, as mentioned previously, the ultimate result of the cementless procedure is a stronger fixation because of the bony ingrowth.