overview depuy hip replacement

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					                                    DePuy Hip Implant Information

DePuy Hip Implants were approved for use in 2005 to replace damaged hip
sockets. The DePuy ASR Hip Replacement Systems are part of a metal-on-metal
bearings class of joint replacement systems (pictured). In some cases this type of
hip replacement system can generate debris through its normal wear, which can
lead to inflammation and tissue damage. Complaints began in 2007, and the
number of reported DePuy hip replacement problems had doubled by 2008, and
tripled by 2009. In August of 2010, DePuy Orthopaedics, a division of the blue chip
medical firm Johnson & Johnson, issued a voluntary recall for two of its ASR hip
replacement devices.

The two recalled devices are:

    1. ASR XL Acetabular System
    2. ASR Hip Resurfacing System

How they work

Both of these devices replace the acetabulum, which is a ball and socket joint in the hip (pictured below).

The DePuy ASR XL Acetabular System is a metal-on-metal device made of “high carbon content” alloy. ASR
stands for Articular Surface Replacement. The ASR XL has high-performance bearings that “articulate” the ball
and socket joint. The ASR or “ASRT” Hip Resurfacing system has fewer components. With this device, a simple
“hip cup” replaces the acetabulum. With both products, the “femoral head,” or top of the femur bone (pictured
above), operates against the artificial rounded portion that is a substitution for the rounded acetabulum.
                                    DePuy Hip Implant Information

The ASR XL Acetabular System, which was used to replace the total hip, consisted of three components:

       A femoral stem inserted into the patient’s femur
       A femoral head connected to the stem that fit into the acetabulum
       A single-piece, metal lined cup used to replace the acetabulum

The ASR Hip Resurfacing System consisted of two components:

       A cap that fit over the natural femoral head
       The cup replacing the acetabulum described above

All of these components in both systems are included in the recall due to the following complications
experienced by many patients implanted with one or the other system:

       Loosening
       Fracture
       Dislocation
       Metal flakes in the bloodstream

Loosening - Although many replacement hips wear out over a 20-25 year period, resulting in loosening, the
defective DePuy hip replacements may become loose within as few as five years or less. Loosening occurs when
the hip replacement does not stay attached to the bone in the correct position. As a result, the patient may
experience pain and difficulty walking or performing other activities involving the hip. The only way to correct
this problem is to undergo more surgery. Since the DePuy hip replacement in question has been recalled, this
second surgery, called a revision, would involve having the ASR hip replacement removed and a brand-new hip
replacement substituted in its stead.

Fracture - In some cases, the bone around the replacement can splinter or break, causing extreme pain and loss
of mobility. Again, the only resolution for this is another hip replacement surgery. This time, the patient has to
experience the added pain and time away from his or her life activities to heal from the fracture as well as the
second operation. Also, once the bone is fractured, it adds to the technical difficulty of removing and replacing
the attaching device during surgery.

Dislocation - When a dislocation of a component occurs, the two parts of the hip replacement that move against
each other, the ball and socket arrangement, are no longer correctly aligned. This can severely impair range of
motion as well as cause pain. As in the case of loosening and fracture, the only resolution is revision surgery and
replacement of the misaligned components.

Metal Flakes - Because the ASR hip replacement systems both involve metallic components that move against
one another, the friction causes small metal particles to flake off and enter the patient’s bloodstream. Although
the Depuy Orthopaedics website states that “these particles do not cause problems for most patients,” they do
acknowledge that some patients may suffer reactions as a result. What they don’t detail is that these reactions
may be toxic in nature, causing pseudotumors, or soft tissue masses that can result in pain, and swelling. If left
untreated, there could be damage to the muscles, bones and nerves around the hip.
                                    DePuy Hip Implant Information

Failure Rate

DePuy ASR hip replacement systems have had a high failure rate of one in eight over five years. This over twice
the industry standard.

The two main causes of danger:

    1. Chance of dislocation over time in which a dislocated or badly aligned ASR hip replacement implant
       threatens the integrity of the joint
    2. The potential of “metal ion flaking” in which small metal bits come off of the metal-on-metal ASR hip
       replacement device and get into the surrounding tissues. This can cause pain, swelling and other
       symptoms in the sensitive tissues around the joint.

Signs/Symptoms of a defective hip replacement:

    -   Elevated pain levels
    -   Loose feelings or sounds in the joint




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