Each year approximately 700,000 people undergo knee replacement surgery to relieve pain or regain mobility lost to osteoarthritis. And, in most cases, they experience good results. After all, knee implants are designed to last for up to 20 years or more and are usually a permanent solution for older patients.
However, around 10% of recipients experience knee replacement failure. In these cases the patient will usually need revision knee replacement. This is a surgical procedure where the old implant is removed, any damaged bone or tissue is repaired, and a new knee system is reinstalled.
The revision may be partial, where certain defective parts are replaced, or total, where the entire implant system is removed and replaced.
A number of factors may contribute to knee replacement failure, whether from complications in the body or early malfunction of the implant itself. Some of the most common reasons for knee revision surgery are:
In most cases, patients will experience ongoing symptoms that signal knee implant failure long before it is identified by a doctor. Some of these include:
If you’ve experienced any of these symptoms for an extended period, you should talk with your doctor. They can perform a bone scan, x-rays or MRI testing to identify potential problems and determine if you need a revision.
When your knee implant was originally installed, doctors secured it to your femur bone on top and the tibia bone below so that it could function like a natural knee joint. This is usually done with bone glue or by placing the implant in position so that bone will grow around it.
It is essential that your knee implant remain fastened tightly to your leg bones in order for it to work properly. Sometimes, however, the device can become detached from your bone.
Knee implant loosening of the DePuy Attune can cause a variety of problems that will lead to the need for revision surgery, like pain, instability, excess bone wear, scar tissue or infection.
It is usually caused by excessive patient body weight, high-impact use, or a wearing out of the knee implant after its useful life.
Sometimes, in a condition known as osteolysis, the small plastic particles from the implant spacer can cause an autoimmune response that attacks the healthy bone around the implant. Excessive foreign particles may also cause blood disorders or infection.
In the case of one popular the lower tibial plate was designed to be so smooth that it wouldn’t properly bond to glue in many cases, leading to a redesign/recall.
Knee implant loosening is more common in younger patients who are more active, or who outlive the intended lifespan of their device.
Like with any surgery, knee replacement procedures have a risk for infection. This can happen right after the surgery or even years after. Either way, infection is the number one cause for failed knee replacement and the need for revision surgery.
Infections may develop in and around the knee implant itself, or may spread to the implant from nearby areas like the foot. Therefore, doctors will prescribe heavy antibiotics to fight the spread of infections in those with orthopedic implants.
Once an infection reaches the implant device, it can lead to stiffness, swelling, bone detachment, drainage or the body rejecting the foreign materials. Any of these can necessitate a revision surgery.
There are different options a doctor may use to fight infection in those with a knee implant.
Fortunately for some, doctors can perform a limited debridement procedure, in which bacteria is cleaned out, the plastic implant spacer is replaced, and the metal portions of the device bonded to the bones are left in place.
In cases of more severe infection, it may become necessary to remove the original knee implant entirely through a staged surgery. This type of procedure actually requires two separate operations. In the first, doctors will remove the implant, place an antibiotic-laced spacer in the knee and wait several weeks for the infection to clear. Then, in a second operation, they will remove the spacer and install a new knee implant.
While a staged surgery has a greater potential to remove the infection, it is much more invasive, costly and timely. Staged surgeries also require longer periods for recovery.
Due to the complications associated with infections, anyone with an orthopedic implant device is cautioned to monitor for symptoms such as pain, swelling, numbness or burning That way, they can notify their doctor and receive the necessary care as soon as possible to avoid surgery.
The initial surgery to implant a prosthetic knee device is known as Primary Knee Replacement, while the second surgery needed to replace this device is known as Revision Knee Replacement.
While these surgeries are similar and may involve many of the same components, it’s important to recognize they can have different levels or risk and patient outcomes.
First, a revision knee surgery is a longer, more complicated procedure. Whereas in Primary Knee Surgery the doctor only has to form your existing bone to accept the knee implant, a Revision Surgery requires removal of the first implant, repairing tissue damage, then refitting a new device.
Often, the removal of the first implant leaves less bone for surgeons to work with, so they must form the remaining bone, graft new bone from donors or other areas of the body, or use augment pieces to fill areas of missing bone.
Second, the knee implant components used in a revision surgery may be different than those used in a primary surgery to account for lost bone space. Examples are longer stems that penetrate deeper into the femoral or tibial bones for added strength.
Finally, the revision procedure as a whole takes more planning prior to surgery, specific tools not used in primary knee replacements, and greater skill by surgeons and operating room support staff.
Doctors note that, while primary knee replacements are intended to last around 20 years, revision knee replacements often only last about half that long. Patients may also experience some lingering pain and restricted range of motion. This is due to the added scar tissue, risk for complications and overall trauma to the surrounding area.
Despite this, the overwhelming majority of patients undergoing revision surgery have positive results. Most report less pain, greater mobility and more stability than they had before the procedure.
There are currently five manufacturers that make the majority of all knee implants used in replacement and revision knee surgeries. Since 2003, the FDA has noted over 700 recalls of various knee systems, components or surgical tools.
Below are a few of the more popular brands and models, along with recent recalls. Note that recalls may only include certain sizes or components.
Zimmer – The most widely-used implant manufacturer, with greater than 25% of all devices sold. Some of the most popular models include:
The most widely-used implant manufacturer, with greater than 25% of all devices sold. Some of the most popular models include:
Biomet recently merged with Zimmer to form the company Zimmer Biomet. Some of their most popular implants include:
Offers knee replacement implants custom-made and sized for each individual patient using 3D imaging and printing technology.
Stryker is one of the largest manufacturers of orthopedic and medical devices in the world. Their most popular knee implants include:
A subsidiary of Johnson & Johnson, DePuy Synthes offers a wide range of knee, hip and shoulder implant devices. Some of their knee systems include:
U.K. based medical supplier manufacturers orthopedic, trauma, surgical, and wound care products in more than 120 countries. S & N knee implants include:
In this section we provide helpful information for any patient about to undergo a knee replacement surgery.
Our natural knee joint consists of an interconnected system of bones, ligaments, cartilage and compartments. Three bones include the femur (upper bone), tibia (shin bone) and patella (kneecap bone).
There’s a lateral compartment (outside), medial compartment (inside), and patella-femoral compartment (kneecap and behind). Collateral and cruciate ligaments hold the various parts in place while allowing flexibility. Finally, the cartilage of the meniscus allows the joint to bend smoothly and absorb the shock of up and down force.
By comparison, a knee replacement implant device is rather simple. At most, there are five major parts that make up a typical knee implant:
According to a recent study of more than 55,000 procedures performed, the typical revision knee replacement surgery costs an average of $49,360, or $57,000 when inpatient costs are included.
This includes an average hospital stay of 5 days. However, it doesn’t include the lost productivity and time missed from work by either the patient or immediate family, nor does it include the months of rehabilitation typically required after revision surgery.
The study, which was conducted in 2010, estimates that the need for revision knee replacements will increase 500% by the year 2030.
If your doctor has recommended revision knee surgery, you may have concerns over the complexity of the procedure, the lengthy hospital stay and rehabilitation required, as well as the risk for further damage to your knee.
However, rest assured that revision surgery has become a common procedure, with the majority of patients experiencing substantial relief of their pre-operative symptoms and years of improved mobility.
Once your doctor orders the procedure, you may return for several imaging tests, office visits or physical evaluations so that your surgeon can properly plan for the procedure ahead of surgery day.
Then, if you’re among those with a chronic condition like heart disease or diabetes, you may require further evaluation and clearances from your cardiologist, endocrinologist or other specialists.
Finally, as you prepare for your revision knee surgery, there are several things you can do to ensure your operation and recovery go as smoothly as possible.
Many of the steps for your revision surgery will be similar to when you underwent initial knee replacement. First, you’ll be instructed to refrain from eating the night before since you will likely be given a general anesthetic.
Next, you’ll be admitted to the hospital on the morning of your surgery. In pre-op, you will first meet with the anesthesiology team to discuss the type of anesthesia to be administered, and the steps going into and coming out of surgery.
Although some knee surgeries can be performed under regional or local anesthesia, your surgery will be done with general anesthesia due to the complex and highly invasive nature of revision replacements.
Next, you’ll meet with your surgeon who will describe the procedure to be performed and confirm which knee will be operated on.
The surgery itself will take around 2-3 hours, slightly longer than your original knee replacement procedure. The doctor will make an incision along the same line as your first surgery, only slightly larger to allow removal of your old implant.
Your surgeon will then move your patella (kneecap) and tendons out of the way to reveal your knee joint. They will conduct a thorough evaluation of the tissue around your knee to check for signs of trauma or infection and will look at your knee implant to see what parts have become worn, loose or inoperable.
Once your doctor has determined whether to replace part or all of the knee implant, they’ll remove those components, as well as any glue used to bond it to your bones. This is one of the most complex parts of the revision surgery as the surgeon tries to save as much of your leg bones as possible.
If removal of the old implant requires significant bone loss, your doctor may use metal pieces called augments to fill the spaces. In some surgeries, they may also use bone grafts from donors or other parts of your body.
During this process, your doctor will also shape and prepare your upper and lower bones to fit the new revision implant components. Lastly, they’ll install and bond the new knee implant, repair any tissue damage, then test the movement of the new knee.
Once surgery is completed, you’ll be taken to a recovery room until you wake up and the effects of the general anesthesia wear off. You will then be transferred to a normal hospital room for further recovery.
For the first few days after your surgery, you’ll likely remain in the hospital for pain management and monitoring for infection, proper drainage or any other complications.
This recovery period will be similar to your first knee replacement surgery, although the process will usually take a bit longer.
After you’re discharged, you will continue to receive treatment at home from a nurse or designated family member for several weeks while you recover. Over the next several months, your treatment will focus on pain management, preventing infections and blood clots, and rehabilitation.
Although some pain is a normal part of the recovery process, your doctor will try to limit this through pain management. This practice uses a combination of oral and injectable drugs like local anesthesia, anti-inflammatories and painkillers. Due to the addictive nature of some drugs, your doctor will limit use to only as much as you need.
Your nurse, or sometimes a family member, will have the important role of wound care and monitoring for infection. This includes regularly changing your bandages and making sure you take antibiotics after your surgery. While your incision heals, it’s important to not submerge it in water.
As you begin the natural healing process, there’s a greater risk for blood clots in other parts of the body like the upper leg and lungs. To combat this, your doctor may prescribe anticoagulant medication or compression fittings.
You’ll also start a physical therapy program soon after your surgery, which is almost as important as the surgery itself in helping you regain maximum mobility. Physical therapy helps strengthen your knee and leg, practice moving them regularly, and prepare you for walking and other normal daily activities.
Some of your physical therapy will take place at a rehabilitation clinic, while other activities will be prescribed for you to do at home. This will continue until you’ve reached a specific goal of knee flex motion, usually around 90 degrees. Even after your in-office therapy has ended, it’s important to continue home exercises to regain strength and mobility.
Finally, your recovery will depend on the use of assistance devices like crutches, walkers or a cane for the first few weeks, as well as the help of friends or family to perform activities like cooking, cleaning and personal hygiene.
During this time, it is important to keep your scheduled follow-up appointments, and adhere to your doctor’s recommendations for medications, wound care and rehabilitation.
In the end, you should look forward to many years of painless mobility and a much improved quality of life compared to your old knee implant.
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