Hip Resurfacing
Rationale
Hip replacement materials are man-made and can wear out over time. When hip replacement is performed on a young, active patient, this wear can be accelerated because of higher demand and activity. Even though many advances have been made which have increased the longevity of hip components, the need for revision hip replacement is still very common.
When a traditional hip replacement is performed, the neck of the femur is cut and a stem is placed down into the femur. The socket is also resurfaced. This procedure removes bone from the femur and the socket. When a hip needs to be revised, this bone loss will affect the complexity of the revision operation and make it more difficult.
Hip resurfacing is a procedure which conserves more bone and matches anatomy more closely. Therefore, should revision be needed in the future, more bone is present and the operation is less complex.
With hip resurfacing, the minimum amount of bone is removed so that the anatomy of the patient is reproduced as closely as possible.
What are the advantages of this?
When we match anatomy closely, with a larger ball size and a closer relationship between socket and ball size, we can increase stability and range of motion. Also, the materials used in concert with the design actually creates less wear than traditional hip components. These hips allow more natural range of motion and higher activity levels. As you may know, professional bicycle racer and Tour de France winner* Floyd Landis underwent hip resurfacing surgery for damage to his hip after a crash. He continues to train and ride at an elite level after surgery.
What are the limitations of this?
Since we are trying to match the anatomy of the patient, we have less control over leg length and orientation of the components than with traditional hip replacement. It is not possible to correct deformity or leg length with this procedure.
For these reasons, there are strict criteria for patients who can undergo the procedure. This operation is for people with strong bones, normal anatomy and alignment, normal kidney function, younger age and minimal difference in leg lengths. People who are obese, have osteoporosis or a great deal of bone loss are not candidates for this surgery. Patients with Rheumatoid Arthritis have been found to have more complications from this procedure, so it is not recommended for these people. Women of childbearing age who plan to become pregnant are not candidates for this surgery. Also, patients with metal allergy are not candidates for this surgery.
It can become clear during surgery that this procedure cannot be performed. It may be necessary to make an intraoperative decision to convert to a traditional total hip replacement. Your surgeon will discuss this with you before the procedure, and you will need to give consent for both operations before surgery.
What are the possible complications?
Like with any orthopedic procedure, there are surgical risks of infection, blood clots and medical complication. These implants are man-made and will wear out over time. The implants can also become loose over time. Like with any hip prosthesis, the artifical hip can dislocate.
Also, because metal-on-metal bearing surfaces are used, there will be an increased number of metal ions in the blood. This has not been shown to be harmful. Testing about the long-term effect is ongoing. For this reason, women of childbearing age are counseled that they ought not become pregnant after hip resurfacing surgery. Most surgeons will not perform this surgery on women of childbearing age.
Is this "Minimally Invasive Surgery?"
No. Since the surgeon must match anatomy closely, this surgery requires a much better view of the bones involved. Therefore, the incision is typically a little longer than is used for traditional total hip replacement. Blood loss is also greater because of the need for increased exposure, so patients ought to be aware of the possible need for transfusion after surgery.
What is the recovery period?
Most people stay in the hospital for 2 or 3 days after surgery. Some will go to an inpatient rehabilitation facility after surgery. Some people will go home after the hospital stay. All patients will undergo physiotherapy to regain strength. There are precautions which will need to be followed to reduce the chances of dislocation. These are similar to the hip precautions after total hip replacement. However, as the resurfacing operation gives better stability, there are fewer limitations on activity.
The human body takes between 9 and 12 months to heal completely after surgery. Patients will begin to feel "normal" after a few weeks, but will still experience changes related to the healing process. Follow up with the surgeon will occur at 3- to 6-month intervals over the first two years. After that, visits to the surgeon are yearly unless there are issues.
A good reference is located at activejoints.com. This site reviews the different systems in use in the US today and discusses patient and surgeon factors.
*Mr. Landis was stripped of his title under suspicion of using performance-enhancing substances. Personally, I still consider him the winner.