BIRMINGHAM HIP Resurfacing System

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DISEASES OF THE HIP

There are four primary diseases of the hip that may indicate the need for BIRMINGHAM HIP Resurfacing.

Osteoarthritis

Osteoarthritis of the hip is a disease which wears away the cartilage between the femoral head and the acetabulum, eventually causing the two bones to scrape against each other, raw bone on raw bone. When this happens, the joint becomes pitted, eroded and uneven. The result is pain, stiffness and instability, and in some cases, motion of the leg may be greatly restricted. Patients with osteoarthritis often develop large bone spurs, or osteophytes, around the joint, further limiting motion. Osteoarthritis is a common, degenerative disease, and although it most often occurs in patients over the age of 50, it can occur at any age, especially if the joint is in some way damaged.

Causes—Osteoarthritis of the hip is a condition commonly referred to as "wear and tear" arthritis. Although the degenerative process may accelerate in persons with a previous hip injury, many cases of osteoarthritis occur when the hip simply wears out. Some experts believe there may exist a genetic predisposition in people who develop osteoarthritis of the hip. Abnormalities of the hip due to previous fractures or childhood disorders may also lead to a degenerative hip. Osteoarthritis of the hip is the most common cause for both total hip replacement and hip resurfacing.

Symptoms—The first and most common symptom of osteoarthritis is pain in the hip or groin area during weight bearing activities such as walking. People with hip pain usually compensate by limping, or reducing the force on the arthritic hip. As a result of the cartilage degeneration, the hip loses its flexibility and strength, and may lead to the formation of bone spurs. Finally, as the condition worsens, the pain may be present all the time, even during non weight-bearing activities.

Rheumatoid Arthritis

Unlike osteoarthritis, which is a "wear and tear" phenomenon, rheumatoid arthritis is a chronic inflammatory disease that results in joint pain, stiffness and swelling. The disease process leads to severe, and at times rapid, deterioration of multiple joints, resulting in severe pain and loss of function.

Causes—Although the exact cause of rheumatoid arthritis is unknown, some experts believe that a virus or bacteria may trigger the disease in people having a genetic predisposition to rheumatoid arthritis. Many doctors think rheumatoid arthritis is an autoimmune disease in which the synovial tissue of the joint is attacked by one's own immune system. The onset of rheumatoid arthritis occurs most frequently in middle age and is more common among women.

Symptoms—The primary symptoms of rheumatoid arthritis are similar to osteoarthritis and include pain, swelling and the loss of motion. In addition, other symptoms may include loss of appetite, fever, energy loss, anemia, and rheumatoid nodules (lumps of tissue under the skin). People suffering with rheumatoid arthritis commonly have periods of exacerbation or "flare ups" where multiple joints may be painful and stiff.

Developmental Dysplasia of the Hip

Developmental dysplasia of the hip (DDH), also called hip dysplasia, is a lifelong condition, shared by one in 1,000 people. Because DDH patients are born with an altered hip anatomy, the joint doesn't develop the normal wear patterns over the years. This leads to "wear and tear" arthritis at a relatively early age.

Causes—The most significant risk factor for DDH is a family history of the disorder. Women have a higher rate of DDH, as do first-born children and babies delivered breech.

Diagnosis—Developmental dysplasia of the hip often can be diagnosed in the first year of life.

>Symptoms include diminished leg movement in the affected hip, shortening of the leg on the affected side, or asymmetry in leg positions. One or both hips may have DDH.

Avascular Necrosis

Avascular necrosis (AVN) of the hip results when poor blood circulation starves the bones that form the hip joint. In time, the starved bone dies, and the hip joint collapses.

AVN, sometimes called hip osteonecrosis, is most prevalent in younger or middle-aged adults.

Causes—Alcoholism and corticosteroids are by far the leading causes of AVN. In rarer cases, AVN can result from a blockage in blood vessels from sickle cell anemia or fat particles, or from dislocation of the hip due to trauma.

Symptoms—Hip pain, especially after standing or walking, is the most common symptom. Hip AVN most commonly afflicts the femoral head, where the femur (or thighbone) attaches to the pelvis (or hip bone). The femoral head may weaken and collapse.

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NON-SURGICAL ALTERNATIVES TO BIRMINGHAM HIP RESURFACING

Before deciding on Birmingham hip resurfacing, your physician may try several non-surgical, conservative measures to relieve the pain and inflammation in your hip.

Lifestyle Modification

The first alternative to hip replacement involves such lifestyle modification measures as weight loss, avoiding activities involving long periods of standing or walking, and the use of a cane to decrease the stress on the painful hip.

Exercise and Physical Therapy

Exercise and physical therapy may be prescribed to improve the strength and flexibility of your hip and other lower extremity muscles. Your exercise program may include riding a stationary bike, light weight training and flexibility exercises. An aquatic therapy program is especially effective for the treatment of arthritis since it allows mild resistance while removing weight bearing stresses. For an appropriate exercise program, contact an experienced physical therapist.

Anti-inflammatory Medications

Arthritis pain is primarily caused by inflammation in the hip joint. Reducing the inflammation of the tissue in the hip can provide temporary relief from pain and may delay surgery.

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) may be prescribed to decrease the inflammation associated with arthritis. A new classification of NSAIDs, called Cox-2 inhibitors, are often very effective in decreasing pain.

In a small number of cases, the doctor may prescribe corticosteroids, such as prednisone or cortisone, if NSAIDs are not effective. However, due to the higher rate of side effects associated with corticosteriods, a physician must closely monitor their use.

Glucosamine/Chondroitin

Two dietary supplements, Glucosamine and Chondroitin (commonly available in a combined tablet), may decrease the symptoms of hip arthritis. Glucosamine and Chondroitin sulfate are both naturally occurring molecules, and issues associated with both remain under active research. However, it appears that many people taking these nutrition supplements on a regular basis note a decrease in their arthritis symptoms.

There exist a number of non-surgical alternatives to total hip replacement surgery. Such measures as lifestyle modification, exercise and physical therapy, and medication should be implemented before deciding on surgery. If all of these measures have been exhausted and your orthopedist recommends surgical intervention, BIRMINGHAM HIP Resurfacing can be very successful in decreasing pain and greatly improving function.

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THE HIP RESURFACING PROCEDURE

Until just recently, your orthopedist would likely be recommending total hip replacement surgery at this point of your disease state. While it is clearly a more bone-sacrificing procedure than hip resurfacing, total hip replacement is a safe and effective surgery, and is performed more than 300,000 times per year in the United States.

Hip before surgery

Implant components

As you may know, total hip replacement requires the removal of the femoral head and the insertion of a hip stem down the shaft of the femur. Hip resurfacing, on the other hand, preserves the femoral head and the femoral neck. During the procedure, your surgeon will only remove a few centimeters of bone around the femoral head, shaping it to fit tightly inside the BIRMINGHAM HIP Resurfacing implant.

Your surgeon will also prepare the acetabulum for the metal cup that will form the socket portion of the ball-and-socket joint. While the resurfacing component slides over the top of the femoral head like a tooth cap, the acetabular component is pressed into place much like a total hip replacement component would be.

BIRMINGHAM Hip Resurfacing System—CUTS	Total Hip Replacement—CUTS
IMPLANT	IMPLANT

» Watch an animation of the procedure

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THE IMPLANT

The BIRMINGHAM HIP Resurfacing implant is not brand new. It has been in use around the world since 1997 and has since been implanted more than 60,000 times. It is new to the United States, however, where it was approved for use by the Food and Drug Administration in May 2006.

Although hip resurfacing is not a new concept, the technology behind the ground-breaking BIRMINGHAM HIP was developed by British orthopedic surgeons Mr. Derek McMinn and Mr. Ronan Treacy. The two surgeons now train orthopedists from around the globe on behalf of London-based medical device manufacturer Smith & Nephew. US surgeons given access to this implant may travel to England for specialized training or may train at one of the few US centers capable of hosting these focused sessions.

Patient Benefits

The benefits to patients of the BIRMINGHAM HIP Resurfacing technique and implant are clear. The implant's head size, its bearing surfaces, and its bone-sparing technique make it a preferred choice for young, active patients. While the implant's rate of survivorship is comparable to standard total hip replacements after five years, these three key advantages set the resurfacing technique and implant apart from its total hip replacement counterparts.

Head Size

The most noticeable aspect of this implant is its size. While it closely matches the size of your natural femoral head, it is substantially larger than the femoral head of a total hip replacement. This increased size translates to greater stability in your new joint, and it decreases the chance of dislocation of your implant after surgery.

Dislocation is a leading cause of implant failure in total hip replacement. While total hip implants dislocate at a rate of one to three-percent over the lifetime of the implant, a study of 2,385 BIRMINGHAM HIP Resurfacing patients found that dislocation occurred in only 0.3-percent of cases five years after surgery.

Bearing Surfaces

BIRMINGHAM HIP Resurfacing takes advantage of one of the orthopaedic medical industry's most technologically advanced bearing surfaces. That means that the surfaces of the ball and the socket are made from materials that dramatically reduce joint wear when compared to traditional hip implant materials.

In this case, both the ball and socket are made from tough, smooth cobalt chrome metal. Traditionally, only the ball is made from cobalt chrome, and the socket is lined with a plastic cup. While this plastic cup has some design advantages, it does wear out over the course of many years since it rubs against the metal ball at a rate of nearly two million footsteps per year in physically active adults.

The plastic particles released into the area around the joint as a result of this plastic wear can lead to a condition called osteolysis, which causes the bone around the implant to soften, become unstable, and ultimately a corrective surgery and new implant are required.

However, when both surfaces of a hip implant are made from cobalt chrome, wear particles are reduced by 97-percent1, thus potentially extending the life of the implant.

There may be risks associated with metal-on-metal hip implants, though. While no evidence has been established on the subject, some are concerned that the increased level of metal ions found in the blood of metal-on-metal hip recipients may have negative effects on the human body. For this reason, some surgeons may not implant such a device in a patient with kidney disease (since healthy kidneys filter ions from your body) or in women who are or may become pregnant.

Bone Conservation

Perhaps the greatest benefit of the BIRMINGHAM HIP Resurfacing implant is the fact that it conserves substantially more bone than a total hip replacement. This is important for two key reasons. First, unlike a total hip replacement, the BIRMINGHAM HIP Resurfacing preserves your natural femoral neck. It is this neck length and angle that determines the natural length of your leg, and since it is not removed and replaced with an artificial device during a resurfacing procedure, concerns regarding leg length discrepancy are virtually non-existent.

Second, if your surgeon should determine you need to have your BIRMINGHAM HIP implant replaced at some point in the future, you may undergo a regular total hip replacement surgery. If you had originally undergone total hip replacement instead of hip resurfacing, you would be dealing with a more traumatic and complex procedure and you would be receiving a more invasive implant.

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