The Birmingham Hip Resurfacing (BHR) is a metal-on-metal prosthesis used in hip resurfacing procedure. Hip Resurfacing is a bone conserving procedure where the acetabulum (hip socket) is replaced and femoral head is resurfaced. Hip resurfacing is indicated in all the individuals with arthritis where conservative treatment was a failure. Advantage of hip resurfacing procedure is that the little bone is removed from femoral head and this spares the femoral canal.
The conventional method of total hip replacement offers poor long-term outcomes for young and active patients leading to the further complications such as revision surgery and associated problems.
In hip resurfacing, the articular surfaces of the femur and acetabulum are replaced. The procedure is bone conserving as most of the head of the femur is retained. Instead of removing the head completely as with a total hip replacement, it is shaped to accept a low-wear metal sphere. This sphere matches the patient's own anatomy that confers low risk of dislocation, a broad range of movement and excellent stability. A comprehensive range of sizes is offered to address the needs of almost all patients, and those with acetabular deficiencies.
The BHR offers a bone conserving, less invasive alternative to total hip replacement, with the potential for higher levels of patient activity. The BHR device is designed to suit cemented fixation or cement-less press-fit fixation. The resurfacing femoral head and acetabular cups are available in various sizes to suit everyone’s needs. The BHR system has allowed many young and active patients, athletes, and sports personalities with arthritic hip to perform their normal activities with no or minimal pain. It can be used in all individuals aged <60 years and in individuals aged>60 years with bone quality strong enough to support the implant.
Last updated 4/29/2017
Total hip resurfacing arthroplasty is a type of total hip replacement where the femoral component is placed upon the femoral neck. This is in contrast to standard hip replacements where the femoral neck is cut and a stem is placed into the proximal femur. The bearing surfaces (the pieces that contact one another) for current resurfacing total hip replacements are metal and are machined to very high tolerances to minimize the amount of debris in the joint. These so called “metal on metal” bearings are also used with some standard total hip replacements. Metal on metal bearings have been used in total hip replacement for greater than 30 years. Studies have shown that metal on metal bearings produce detectable amounts of ions in the liver, kidney, and urine. In spite of this, there have been no cases of cancer reported as a result of the metal on metal hip replacements up to now. Metal on metal bearings allow the surgeon to use larger diameter femoral and acetabular components which leads to a improved range of motion and potentially a lower dislocation rate. The additional benefit (and more important benefit) of resurfacing total hip replacement is the preservation of native bone in the femur. This would minimize the risk of debris traveling down the bone leading to bone digestion (osteolysis). Also, if a patient with a resurfacing total hip has a fracture of the neck of the femur, in many cases, the hip can be treated with conversion to a standard total hip replacement. However, this benefit does come at a cost.
The major problems with resurfacing include the requirement of using a metal on metal bearing, the risk of loosening of the femoral component (in cases of large cysts or inadequate bone), and the technical difficulty of the surgery. The surgery is more challenging since the femoral neck remains intact and can obstruct the view of the hip socket (acetabulum). Not all patients are candidates for resurfacing total hip replacement. In particular, patients who have large cysts in the femoral head or hip socket, low bone density, those with a great degree of deformity, or extensive bone spurs around the hip socket would be best treated with a standard hip replacement. Other complications include infection, nerve injury, fracture of the femoral neck beneath the resurfacing implant, impingement or abnormal contact between the neck of the femur and the edge of the cup, loosening of the implants, and persistent pain.
The following case is an illustration of the steps involved in a resurfacing total hip replacement performed in a 58 year old male with osteoarthritis of the right hip.
1.These radiographs show advances arthritis of the right hip. The architecture of the femoral head is consistent with femoroacetabular impingement as the underlying cause of the osteoarthritis. The patient elected to have right hip resurfacing total hip replacement.
2.A posterior approach to the hip was selected. The patient is positioned with his left side down and is fixed to the table using supports. The hip is approached with release of the soft-tissues to allow the femoral head to be retracted forward, exposing the hip socket.ral neck, a cylindrical reamer is passed over the femoral head, removing bone at the periphery of the femoral head.
3.After the femoral head is exposed and a guidepin is passed down the shaft of the femoral neck, a cylindrical reamer is passed over the femoral head, removing bone at the periphery of the femoral head.
4.After removal of this device and placement of the cup the head is inspected to be sure that all peripheral bone has been removed. Next a special reamer device is passed over the head in order to shape it to match the inside of the femoral resurfacing implant.
5.Next, drill holes are made at the top of the head and on the edges to maximize cement fixation onto the femoral head and neck.
6.The femoral component is cemented into place. In the photograph, above the femoral (large black arrow) and acetabular components (small white arrow) are mated and the femoral head is placed within the socket. The range of motion is checked at this point in the surgery.
7.These final radiographs show the implants in the desired position and alignment.
1. What is the difference between a standard hip replacement and a resurfacing total hip replacement?
Most contemporary metal hip replacements are made of titanium alloys or cobalt-chromium alloys. The best way to understand the implants used in current replacements is to divide them into two parts. First is the metallic components that are directly fixed to the bone. These can be either through the use of cement (mostly on the femur or thigh-bone) or through a cementless or ingrowth process where the bone actually grows onto the metal. The second part of the hip replacement is made of the parts that actually move relative to one another (the bearing). These can be made of either metal on polyethylene plastic (most common) or other bearings such as ceramic-on-ceramic or metal-on-metal.
2. How long will I be in the hospital?
In most cases, patients remain in the hospital at our facility for a minimum of 2 days and usually 3-4 days.
3. Would I go home or go to a nursing facility after the surgery?
This depends on how much help you have at home. The goal of physical therapy both in the hospital and at home is to get you to be independent. If this can not be acheived while you are in the hospital, a vigorous course of therapy in a skilled nursing facility is the best answer to continue to progress toward independence.
4. Can I put my full weight on the leg after a resurfacing total hip replacement?
In most cases of ingrowth prostheses, we restrict the amound of weightbearing on the leg for 4 to 6 weeks. This has been shown to lead to decreased risk of the stem collapsing into the femur
5. What are the advantages of the resurfacing total hip replacement ?
The greatest advantage to the resurfacing hip replacement is the preservation of the patient's bone. By maintaining as much bone as possible in the femoral neck, there is a potential for the bone to continue to be loaded mechanically. This is theorized to lead to increase mineralization in the bone and avoid a complication known as "stress shielding" where the bone that is bypassed with a metal implant is not loaded and can ultimately lose its mineralization as seen by radiographs. Additionally, in the young patient, preservation of the bone can provide increased options in the future in the event of implant failure over the years or in case of trauma.
6. What are its disadvantages?
The biggest disadvantage of resurfacing hip replacement is the exposure of patients to increased levels of metal ions as a result of the metal on metal joint. In spite of higher measured levels of the metal ions, no cases of cancer have been reported directly related to metal on metal hip replacements in spite of greater than 30 years of clinical use.
7. Do resurfacing total hip replacements wear out?
Metal on metal hip replacements such as resurfacing total hip replacements can wear out. Their rate of wear is lower than that measured from standard metal on polyethylene hip replacements. At the current time, it is not known how long the expected implant survival would be for a resurfacing total hip replacement.
8. What kind of activity level can I resume after the resurfacing total hip replacement?
Patients with resurfacing hip replacements are not given any specific activity restrictions. However, just like a standard hip replacment, damage can be done to the hip by excessive activity and impact loading activities. These may ultimately lead to a shorter survival of the implant.
9. Do I have to follow any other precautions after my surgery?
You will be kept on crutches or a walker for the first 4-6 weeks after the surgery unless specified differently by your physician.
10. Do resurfacing hip replacements dislocate?
A dislocated hip can occur during activities in which the precautions are not followed or as a result of soft-tissue laxity or impingement. Impingement is a situation where the component or bony structures contact each other in such a way that they push the hip out of socket. Although resurfacing total hip replacements are very stable and not prone to dislocation, they still can dislocate if the patient goes into a very high degree of bending or twisting at the hip.
11. What about the metal ion issue?
Metal ions are released from every type of hip replacement. Metal on metal bearings such as those used in resurfacing hip replacements are associated with higher levels of metal ions. However, there have never been any cases of cancer directly related to the metal on metal prosthesis in spite of over 30 years of use. We would not recommend metal on metal total hip replacements for patients with liver or kidney disease or the potential for developing such disease.
12. What are the long term results with the resurfacing total hip replacement compared to standard hip replacements?
A number of reports have shown no difference in the early term results between the resurfacing and standard hip replacements. However, resurfacing is technically more demanding and may be associated with more complications. Data from the Australian Hip Registry indicates a higher revision rate in females and in males with smaller stature treated with total hip resurfacing. At this point, it is not clear if the benefits of resurfacing outweigh the risks associated with the procedure.