Five Reasons Why Knee Replacements Fail
Wear and loosening
Properly functioning implants depend on their appropriate fixation to the bone. Fixation is usually achieved by cementing the implant onto the bone. Some surgeons prefer instead to use biologic fixation, meaning no cement placed between the implant and the bone.
Although implants are firmly fixed at the initial knee replacement surgery, they may become loose over time. The cause of loosening may not always be clear but high impact activities, excessive body weight and wear of the polyethylene component may all act as contributing factors. Friction caused by the joint surfaces rubbing against each other wears away the surfaces of the implant, creating tiny particles that accumulate around the joint. In a process called aseptic loosening, the bond of the implant to the bone is destroyed by the body’s attempt to digest these wear particles. During this process, normal, healthy bone is also digested , which can weaken or even fracture the bone.
When the prosthesis becomes loose, the patient may experience pain, change in alignment, or instability.
Revision surgery of the infected knee can take several forms. Depending on the degree of infection and damage, the surgeon will determine one of two basic courses of action:
Find The Best Knee Replacement Implant: Top Brands
There are more than a dozen manufacturers of artificial knee implants. However, like anything else, some knee implant manufacturers have a larger market share than others. In the US, the most popular knee replacement parts manufacturers are Zimmer , Stryker, DePuy and Smith & Nephew.
Here are the top brands and styles used by surgeons in the US.
Zimmer is the most popular manufacturer of knee replacements. In fact, according to Zimmer, more than 25% of knee replacements implanted worldwide are a Zimmer product. Thats a whole lotta implants!
Biomet, who has recently merged with Zimmer and is now called Zimmer Biomet, offers a nickel-free implant for those with allergies. They also offer an antioxidant polyethylene material insert component to pair with their tibial and femoral parts. In saything this, there is nothing to prove that antioxidant plastic holds any true benefit. Admittedly, it sounds pretty good though!
Among the most popular manufacturers in the US, Stryker offers total, partial, and revision knee replacement systems that are suitable to a wide variety of patients. Stryker implants are used in over 100 countries.
Smith & Nephew offers a wide range of replacement variations that fall under their Legion family. This includes replacements made from oxidized zirconium, a nickel-free metal thats suitable for patients with metal allergies.
Knee Replacements May Last 25 Years
The study, published in The Lancet, reported eight out of 10 knee replacements last as long as 25 years. This is significant for a number of reasons:
- Twenty-five years is a decade longer than previously thought.
- The research will help patients and doctors better determine if or when to have knee replacement surgery.
- By 2030, primary total knee replacement surgery is projected to grow by up to 189 percent .
Total Knee Replacement Estimate Raised From 15 to 25 Years
Prior to the study, 15 years had typically been cited as the length of time patients should expect an artificial knee joint to last. Fifteen years had been given as a rough estimate because there was no scientific evidence to prove the actual time period joints lasted after joint replacement surgery.
The researchers followed nearly 500,000 patients who had undergone joint replacement surgery over the past 25 years. Specifically, the results showed that:
Among total knee replacements
- 93 percent lasted 15 years
- 90 percent lasted 20 years
- 82 percent lasted 25 years
Among partial knee replacements
- 77 percent lasted 15 years
- 72 percent lasted 20 years
- 70 percent lasted 25 years
Knee Replacement Revision Surgery
After a patient has had joint replacement surgery, sometimes a second surgery, called a revision, is needed to replace the joint. Reasons for revision surgery vary and may include infection in the knee, loosening of the implant, or wear-and-tear of the artificial joint.
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What About Exercise Following A Knee Replacement
Exercise and sport are recommended after knee replacement, apart from contact sports, which may weaken the cement and lead to loosening of the joint components. Recreational sports including golf, tennis and skiing will gradually become possible depending on how fit and sporty you were before the operation. Cycling is a very good way of building up strength and mobility after knee surgery.
Exercising the main muscle groups around your knee is very important both before and after having a knee replacement. You can download a selection of exercises that are designed to stretch, strengthen and stabilise the structures that support your knee. Try to perform these exercises regularly, for instance for 10 minutes six to eight times a day. However, its important to find a balance between rest and exercise so you dont overwork your knee. Its a good idea to get advice from your doctor or physiotherapist about specific exercises before you begin.
Characteristics Of Severe Arthritis Of The Knee
Pain is the most noticeable symptom of knee arthritis. In most patients the knee pain gradually gets worse over time but sometimes has more sudden flares where the symptoms get acutely severe. The pain is almost always worsened by weight-bearing and activity. In some patients the knee pain becomes severe enough to limit even routine daily activities.
Morning stiffness is present in certain types of arthritis. Patients with morning stiffness of the knee may notice some improvement in knee flexibility over the course of the day. Rheumatoid arthritis patients may experience more frequent morning stiffness than patients with osteoarthritis.
Swelling and warmth
Patients with arthritis sometimes will notice swelling and warmth of the knee. If the swelling and warmth are excessive and are associated with severe pain, inability to bend the knee, and difficulty with weight-bearing, those signs might represent an infection. Such severe symptoms require immediate medical attention. Joint infection of the knee is discussed below.
The knee joint has three compartments that can be involved with arthritis . Most patients have both symptoms and findings on X-rays that suggest involvement of two or more of these compartments for example, pain on the lateral side and beneath the kneecap . Patients who have arthritis in two or all three compartments, and who decide to get surgery, most often will undergo total knee replacement .
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What Are The Risks And Complications Of Revision Knee Replacement
Any surgery can have potential complications. The complexity of revision joint surgery increases the chance of surgical complications, which include but are not limited to:
- wound drainage
- damage to nerves or blood vessels
- intra-operative fractures
- pulmonary embolism
Infection, bleeding, damage to nerves or blood vessels, and intra-operative fractures can be minimized by using antibiotics before and after surgery, employing sterile surgical techniques and utilizing well-planned surgical exposures. Patients who are obese are particularly at increased risk of infection and wound drainage issues post operatively.
Similar to primary knee replacement, some mild swelling of the knee or ankle may be present after surgery for as long as three to six months. Swelling can be treated by elevating the leg, applying an ice pack, and wearing compression stockings.
Prior medical conditions, such as heart and lung complications or stroke conditions, can be aggravated by a revision procedure. These conditions may also develop in patients after revision surgery. Very rarely, death can occur. The decision to perform revision joint surgery is made when the benefits of pain relief and functional improvement outweigh the risk of potential complications.
Meeting Your Knees Halfway
If youve exhausted our many conservative treatment options, and your knees are still limiting your life, its time we sit down and discuss replacement. While we do our best to work with what Mother Nature provided, there can come a time when parts of your knee are more of a liability than an asset.
But before we start recreating these large joints in their entirety, we first determine the extent of the damage to see whether a partial replacement is an option. Also called a unicompartmental knee replacement, this technique allows us to go in and replace only whats necessary, taking a leave well enough alone attitude to healthier components.
To do this, we divide your knee into three compartments:
- The medial compartment, found on the inside of your knee
- The lateral compartment, located on the outside
- The patellofemoral compartment, the area on the front of your knee between your kneecap and your thighbone
Once we zero in on your problem compartment, we go in and replace and resurface the components that are damaged with metal and plastic parts, leaving the rest of your knee intact.
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Durability Of Knee Implants: How Long Do Knee Replacements Last
In the 1960s and 1970s, most believed that total knee implants would last about 10 years. This was one of the reasons that knee replacement procedures were confined to older patients. As time passed, it became apparent that the great majority of knee implants would last approximately 20 years and even longer.
Improvements in surgical technique, materials, implant designs and fixation have escalated over the past two decades resulting in increased durability of knee implants well beyond even 20 years. There are many still active patients whose knee prostheses were put in as long as 30-40 years ago! However, as with any medical question, the longevity of a knee implant will vary from patient to patient, due to differing physical condition, activity, weight, skill of surgeon in placing the implant and more.
The age limitations on knee replacement surgery have fallen by the wayside but the concern that younger patients will wear the implant out faster than older patients still persists. Wear was always considered the primary problem but statistics show that wear on the plastic spacer is less of a problem than once thought because of the nature of the bearing which is flatter than in the hip joint where wear is a problem.
If prosthetic knee implant does begin to cause pain, talk with your orthopedic surgeon about whether you might be a candidate for a second knee replacement.
Things No One Ever Tells You About Getting A Knee Replacement
Heres what you need to know thats not in the brochure: 1. You might not be a good candidate.A study published last year by researchers from Virginia Commonwealth University in Richmond questioned the value of knee replacement for some of the people rushing to get it. After analyzing data from a large study of men and women who had the operation, the researchers found that fully one-third of them were not actually good candidates for the surgery, which is why they got only a very modest benefita 2-point improvement on a common measure of knee function, compared with a 20-point improvement for people who started out with really bad knees.
“Pain that doesnt go away and moderate to severe arthritis are necessary for a knee replacement to do its job,” Lajam says. “If you have the surgery, but its actually a problem of nerve pain, hip pain, or circulation, its not going to help you.” The advice here is not to wait until your knees are completely destroyed before seeking surgery, but to make sure that youve tried other measures first and that you meet both criteriaconsistent pain and advanced arthritis.
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Why Do Artificial Joints Wear Out
Nothing lasts forever. Articular cartilage allows our joints to move freely without pain. As that cartilage wears out or becomes damaged, arthritis develops. If the resulting pain and deformity from arthritis becomes severe, many joints can be replaced, usually with metal and plastic implants. However, these artificial joints wear out with time and use.
How Long Will Hip or Knee Replacements Last?
Surgeons expect that the hip and knee replacements that we are implanting today may last twenty years or longer. There are many factors that impact longevity. Patient weight and activity level are important factors. Excessive body weight is a risk factor in the development of arthritis and can contribute to early wear and failure of orthopedic implants. High impact activities such as running and jumping place excessive loads on the components.
What Are Artificial Joints Made Of?
What Happens When An Implant Wears Out?
When an implant begins to wear out, the wear particles from the polyethylene can cause inflammation. This inflammation can loosen the bond between the joint and the bone. It can also cause pain and instability. If significant wear occurs, a revision surgery may be required.
What Can I Do To Make My Artificial Joint Last Longer?
What Is An Artificial Knee And How Does It Stay In Place
Artificial knee implants consist of metal and medical-grade plastic called polyethylene.
There are two ways of attaching the components to the bone. One is to use bone cement, which usually takes about 10 minutes to set. The other is a cement-free approach, in which the components have a porous coating that allows the bone to grow onto it.
In some cases, a surgeon may use both techniques during the same operation.
Any operation done with anesthesia has risks, although it is rare that severe complications result from any type of anesthesia.
The options for TKR include:
- general anesthesia
- spinal or epidural
- a regional nerve block anesthesia
An anesthesia team will decide on the most suitable options for you but most knee replacement surgery is done using a combination of the above.
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What Kind Of Metal Is Used In Knee Replacements
Artificial knee materials can be made of strong plastic, metal, or ceramic. All knee replacements, partial or total, will have parts made of a few different materials . In most cases, each component is built from titanium, cobalt-chromium alloys, or a titanium and cobalt mixed metal. The chosen materials must be durable, allow for some flexibility with movement and be biocompatible .
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Different Types Of Surgery
There are 5 main types of knee replacement surgery:
- Total knee replacement. This is the most common form. Your surgeon replaces the surfaces of the thigh bone and shin bone that connects to the knee.
- Partial knee replacement. If arthritis affects only one side of your knee, this surgery may be a possibility. However, itâs only right for you if you have strong knee ligaments and the rest of the cartilage in the knee is normal. Partial knee replacement can be performed through a smaller cut than is needed for total knee replacement.
- Patellofemoral replacement. This replaces only the under-surface of the kneecap and the groove the kneecap sits in. This can be very effective for people with chronic kneecap arthritis.
- Complex knee replacement. This procedure may be needed if you have very severe arthritis or if youâve already had two or three knee replacement surgeries.
- Cartilage restoration: Sometimes when the knee only has an isolated area of injury or wear this area can be replaced with a living cartilage graft or cells which grow into cartilage.
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How Long Does A Total Knee Replacement Last And What Affects Longevity
Improvements in surgical techniques, materials, prosthetic design, and fixation have improved dramatically over time. As a result, this has significantly increased how long a total knee replacement lasts.
Several factors affect how long a knee replacement lasts. These include the patient’s condition, age, body weight, and the surgical implant.
Younger patients often ask how long does a total knee replacement last and will need the implant to last longer than older patients. As a result, patients who have a total knee replacement may need to have a revision done to replace their implant at some point in their lifetime. To maximize how long a total knee replacement lasts, patients should avoid high impact activities, competitive sports, running, high impact aerobics, and heavy manual labor.
Patients who are overweight place a significant amount of impact on their bodies. Maintaining a healthy weight lowers the amount of stress placed on the new total knee joint. Avoiding complications will also improve how long a total knee replacement lasts.
After the surgery, it is important to follow all orthopedic surgeon instructions and follow up with physical therapy. This will decrease the risk of complications such as infection or limited movement of the knee. Complications can limit how long the knee replacement lasts.
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Understanding Artificial Disc Replacement Surgery
When you move, the discs in-between the bones of your spine provide cushioning, absorbing impact and keeping your bones from rubbing together. But just like many structures in your body, the effects of aging and general wear and tear can cause your discs to degenerate over time. They can shrink and lose their buffering ability, or they can shift out of place, causing inflammation and nerve pain.
One method of alleviating this pain is to remove the damaged disc and replace it with a man-made implant. Artificial discs are designed to replicate natural discs, so they help carry the load of your spine while still allowing for movement. Ultimately, the goal of artificial disc replacement is to keep your spine functioning as it would in a normal, healthy state.
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Research: It Is Unclear Whether Total Knee Replacement Facilitates Weight Reduction Is The Surgery A Barrier To Weight Loss
We do understand that some adult children and spouses may implore their loved ones to get a knee replacement because they have to do something. They are getting heavier and less mobile. In some instances, people can be guilted, into treatment when they perceive that they will be a burden, on their loved ones.
But is knee replacement an answer that will make things better or worse?
An earlier study from the Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University and the Department of Exercise Science, University of South Carolina published in the journal BioMed Central Musculoskeletal Disorders made these observations:
- Most knee replacement patients are overweight/obese, yet are commonly excluded from evidence-based weight loss programs due to mobility limitations and barriers faced around the time of surgery.
- The purpose of this study was to identify knee replacement patient preferences for weight loss programs and qualitatively understand previous motives for weight loss attempts as well as strategies used to facilitate behavior changes.
This study focused on patients who were either scheduled to have knee replacement or had one recently completed within the last 3 months were recruited to participate. Patients completed a brief weight loss program preference questionnaire assessing preferred components of a weight loss program .
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