What Is a Hip Replacement?
A hip replacement is a prosthetic medical device that replaces a damaged hip joint. The hip replacement device is surgically implanted in order to help a patient improve their quality of life and mobility as well as reduce pain. Typically, because a joint replacement is major surgery, it’s not considered an option until other methods have been attempted first. Doctors usually only recommend a hip replacement when the patient is experiencing a negative impact on their quality of life due to pain or loss of mobility.
What Types of Hip Replacement Are There?
There are three types of hip replacement surgeries that can be done, depending on the particular needs of the patient: total hip replacement, partial hip replacement, and hip resurfacing.
What Is Hip Resurfacing?
Hip resurfacing can sometimes be used to prevent bone loss and delay a total hip replacement. As a total hip replacement has a limited lifespan, hip resurfacing may five additional years of mobility before total replacement is required. This increases the chance that a younger patient will outlive any total hip procedure that is required at a later date. Hip resurfacing will include the implanting of a cup lining and femur head covering. It is also used to help reduce mobility and pain issues associated with arthritis.
What Is a Partial Hip Replacement?
A partial hip replacement is recommended when only one of the hip components needs replacement. In most cases, the femur head will be replaced with a new section and the acetabulum will be left intact. In some cases, however, the femur head may be in good condition but the cup section of the acetabulum requires replacement. A partial hip replacement is also sometimes used to correct a broken hip that occurs at the femur neck.
What Is a Total Hip Replacement?
A total hip replacement is required when both sections of the hip joint have shown significant degradation. The procedure involves the installation of a completely new engineered joint to replace both the femur head (ball) and the acetabular cup (socket).
Who Needs a Hip Replacement?
Typically, those who get hip replacements are those whose lives are negatively affected by hip pain and mobility issues that their doctors recommend a hip replacement to improve their quality of life. Signs that you may need a hip replacement include:
- Pain that persists despite taking medication
- It’s difficult to get up from a seated position
- Difficulty walking, even with a walker or a cane
- Difficulty walking up or down the stairs
- Pain interferes with sleep
What Can Cause a Hip Replacement to be Needed?
Hip problems of this degree can be caused by a number of different conditions that both cause hip pain and also damage the hip joint.
What Is Rheumatoid Arthritis?
Rheumatoid arthritis is a disorder in which the immune system of the body attacks its own tissues by mistake. In particular, rheumatoid arthritis affects the lining of the joints, which causes painful swelling. Eventually, this can result in deformity of the joints or the erosion of the bone. Symptoms of rheumatoid arthritis can include:
- Loss of appetite
- Joint stiffness (typically worse after periods of no activity, such as in the mornings)
- Swollen joints
- Warm joints
- Tender joints
What Is Osteoarthritis?
Osteoarthritis, which is the most common of the types of arthritis, damages joints by wearing away at the cartilage that protects the ends of your bones. With osteoarthritis, the cartilage is worn away over time and can’t be recovered, although it can often be managed with a combination of medical treatment and lifestyle changes. Symptoms of osteoarthritis include the following:
- Bone spurs
- A loss of flexibility
- A grating sensation
- A popping or cracking sound when you move the joint
What Is Osteonecrosis?
Osteonecrosis is also known as avuncular necrosis and it occurs when bone tissue dies because it’s not getting enough of a blood supply. Over a period of months or years, osteonecrosis results in tiny breaks occurring in the bones, which ultimately causes the bone to collapse. There are usually no symptoms at all during the earlier stages of the disease, which can be caused by a broken bone, which could stop the blood flow to that bone, the long-term use of certain steroid medications, or drinking too much alcohol. In the later stages, you might feel pain only while you’re moving the affected joint or, after a while, even when you’re not moving. Any ongoing pain in one joint should be reported to a doctor.
What Types of Hip Replacement Devices Are There?
Hip arthroplasty, the technical name for hip replacement can be done with several different implant types. Each type mimics the physiology of the normal human hip. The hip is a ball and socket type joint with the femoral head at the top of the largest leg bone acting as the “ball” and the acetabulum, a cup-shaped area of the pelvis acting as the “socket”. The hip joint can wear out after a period of time and require replacement with an implant that mimics natural movement to allow for continued mobility.
There are different materials used to manufacture hip replacement devices, each with attributes but also with complications.
What Is a Metal Ball with Plastic Cup (MoP) Hip Replacement?
This type of hip implant has been in use since the 1960s. The plastic, made of polyethylene has a smooth surface which minimizes the friction as the ball moves in the socket. The plastic used in the implant is fairly soft and does produce a lot of debris. The breakdown of the liner can lead to osteolysis and will ultimately cause the device to fail as it has a limited lifespan.
What Is a Metal Ball with Metal Cup (MoM) Hip Replacement?
Metal-on-metal implants were designed to increase durability. They use larger ball and socket shapes to provide maximum mobility. Makers market these versions to a younger demographic as they could last longer and promote an active lifestyle. Metal-on-metal implants have been the focus of many recalls and investigations for design defects and failure rates.
What Is a Ceramic Ball with Plastic Cup (CoP) Hip Replacement?
The plastic used in the cup or lining of the socket is harder than that used in the MoP design. The products are fairly reliable, but there is still the change for debris causing a risk of osteolysis.
What Is a Ceramic Ball with Ceramic Cup (CoC) Hip Replacement?
The all-ceramic hip device design has been in use outside of the US since the 1980s but was not approved by the Food and Drug Administration (FDA) until 2011. They are quite durable but have a history of squeaking and shattering.
What Is a Ceramic Ball with Metal Cup (CoM) Hip Replacement?
The ceramic-on-metal version was also approved in 2011. It has been designed to reduce problems that have occurred with the MoM devices. Postmarket studies for safety and performance are still underway.
Who Manufactures Hip Replacement Devices?
The following companies manufacture hip replacement devices:
- Stryker Orthopaedics
- Zimmer Holdings Inc.
- DePuy Orthopaedics
- Smith & Nephew
- Biomet Inc.
- Wright Medical Technology Inc.
What Complications Can Occur with a Hip Replacement?
If you get a hip replacement surgery, the following are complications that could occur:
- Joint dislocation
- Legs being a different length
- Nerve damage
- Blood clots
- Hip Instability
- Lack of mobility
- Revision surgery requirement
- Tissue ossification
- Periprosthetic fracturing
- Muscle tissue loss
What Is Loosening?
Loosening is the process of the joint replacement device coming loose, either from where it is connected to the bone or the components from each other. Typically, loosening has to be correct with revision surgery.
How Does a Hip Replacement Cause Pain and Inflammation?
Pain is the most common side effect of a failed implant. The pain can be caused by the implant’s failure to properly adhere to the hip and leg bone, becoming dislodged. Pain also occurs due to metal releasing small fragments into the surrounding tissue. This causes inflammation, tissue death, and toxicity.
How Does a Hip Replacement Cause Instability and Lack of Mobility?
When a hip joint replacement device malfunctions and does not seat correctly, it may become dislocated and produce instability. This makes movement very difficult or impossible as the implant may grate against the bone resulting in severe pain. The ball and socket may also become dislocated which prevents proper movement and may cause the patient to be unable to move the leg correctly. This is generally reversible when revision surgery is performed but damage to surrounding tissue and bone may be permanently damaged and cannot be fixed with revision surgery.
When Does a Hip Replacement Require Revision Surgery?
Surgery to correct a failed implant may be required due to pain from metal toxicity. Hip implants that become dislocated will also cause extreme pain and immobility. The hip implant will require removal and replacement with a new device. The recovery period from hip revision surgery may be a great deal longer and more painful than the original surgery. In addition, not all of the tissue damage may be reversible, causing permanent injury.
What Is Revision Surgery?
Revision surgery is surgery performed to correct a problem with a hip replacement or to insert a new hip replacement device. Hip replacements are meant to last between 10 and 20 years before wearing out and needing to be replaced. However, they can need to be replaced more quickly if there’s a problem with the device, such as a fault with the hip replacement prosthesis or an adverse reaction.
If you have to have revision surgery sooner than expected, then the chances of needing more total revision surgeries are increased. Revision surgery, like any surgery, comes with its risks. In addition, with each successive surgery for the same hip replacement, more of the patient’s own bone and tissue have to be removed so that the hip replacement can be attached.
Why Is Revision Surgery Necessary?
Revision surgery may be necessary because the hip replacement has failed or has been recalled, or if it’s causing the patient to have an adverse reaction. Typically, the following are the most common reasons for needing revision surgery for a hip replacement device:
- Wear and tear
- Recurring hip dislocation
- Device recall
Your doctor will help you to determine if the risks of revision surgery are greater than the risks of continuing to use a faulty hip replacement device.
What Are the Risks of Revision Surgery?
Revision surgery has all of the same risks as any other surgery:
- Adverse reaction to anesthesia
- Blood clots
With revision surgery, however, the risks of the above complications occurring are typically higher than during the original surgery. In many cases, doctors may only recommend that a patient undergo revision surgery in cases where there is no other option to treat a problem with or reaction to the hip replacement.
This is why some patients may continue to use faulty or recalled hip replacement devices. Their doctor may have weighed the risks of continued use versus those of a revision surgery to replace the hip replacement and determined that the risks of undergoing another surgery were higher than those of continuing to use the device. This means that some patients whose hip replacements have been recalled may have to live with the adverse effects and risks of continuing to use that device and can’t benefit from a replacement for it because the risks of the revision surgery are too high for them.
What Are the Signs Revision Surgery Is Needed?
A hip replacement revision surgery might be needed if you’re experiencing the following:
- Pain while walking
- Limited range of motion in the hip
- Limpness in one leg
- A feeling of instability in the hip joint
What Is Metallosis?
Metallosis is tissue toxicity caused by metal degradation. The metal-on-metal grinding of some hip implants may cause pieces of the metal to flake off. This can become deposited in nearby areas, including the bone.
What Are Osteolysis and Osteonecrosis?
Osteolysis and osteonecrosis are tissue dissolution or death in areas around the implant due to toxicity from metal fragments or plastic. This may result in reconstructive surgery in addition to revision surgery.
What Is Tissue Ossification?
As bone disruption occurs, bone tissue may begin to grow in the soft tissue surrounding the injured joint. This will calcify creating damage to the local tissue which is extremely painful and sometimes causes permanent tissue damage.
What Is Periprosthetic Fracturing?
As the bone around the implant weakens, small fractures may form, making the bone fragile. This fracturing may require reconstructive surgery in addition to revision surgery.
How Are Hip Replacement Devices Approved by the FDA?
The FDA classifies medical devices into three categories based on patient risk. Class I and II devices present less risk to the patient. A Class III device, such as an implanted device, presents a much greater risk in the event of a malfunction. These devices are capable of causing permanent changes. Hip implants are Class III devices that would normally require an application for Premarket Approval (PMA) to be offered for use in the US market. PMA applications require that clinical studies are completed and submitted to the FDA along with numerous other documents regarding design, components, and manufacturing data.
The FDA has an alternative pathway known as 510(k). This is generally used only for Class I and II devices unless the manufacturer of a Class III device shows that a new product is substantially similar to and not substantially different from products that are already approved for use. This pathway is generally intended for upgrades and minor manufacturing improvements. Unfortunately, the FDA allowed the manufacturer of the first metal-on-metal hip implant device to be exempt from PMA requirements.
Hip replacement manufacturer Stryker, for example, claimed that their new design of metal-on-metal was based on already approved devices and allowed the device to be manufactured and used in the US without performing clinical studies. These studies could have identified design defects and adverse events.
Why Are Hip Replacement Devices Recalled?
Hip replacement devices can be recalled for a variety of reasons. Companies recall devices when they discover a problem with the manufacturing process, how the device is stored, or even the product’s design that could cause harm to a patient. Metal-on-metal devices have been recalled, for example, because metal shavings would come off the device and cause damage to the patient’s surrounding tissues.
Are There Lawsuits Against Hip Replacement Manufacturers?
Patients who have experienced adverse side effects may consider lawsuits against the company that manufactured their hip replacement. Hip replacement manufacturers have faced thousands of lawsuits due to claims that they were negligent in some way or failed to warn patients of the risks involved with their device. If you have been harmed by a hip replacement device that has been recalled, first talk to your doctor and then consider a free consultation with a hip replacement lawsuit attorney.
Notwithstanding claims relating to this product, the drug/medical device remains approved by the U.S. FDA.
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