The risk of complications from a knee replacement can result from issues during surgery or a faulty implant. A patient’s own health may increase or prevent many of the risks with surgery. Most complications are minor, but others including fractures and infection can be very serious.
Did you or a loved one suffer complications after receiving a knee replacement? You may be eligible for compensation.
Knee replacement surgery has become a routine surgery and is the most common type of joint replacement in the U.S. More than 600,000 people each year receive this life-improving surgery and are able to enjoy richer, more active lives free of chronic knee pain.
Most knee replacement patients tend to be older than 50 and have arthritic joints. However, an increasing number of younger people are also replacing their knees because of injury from high-impact sports and activities that wear out their knees quickly. Researchers have found that 94 percent of knee replacements last five years and 88 percent last for 10 years or more.
As more advanced surgical procedures and a wider variety of medical devices become available, people have more choices for treatment. Computer-assisted surgeries and minimally invasive procedures increase the accuracy of the surgery and decrease recovery time. Knee implant manufacturers are already marketing robot-assisted surgical devices and Zimmer-Biomet has floated the idea of partnering with major medical centers to develop on-site 3D printing systems that can generate knee implants customized for individual patients in a matter of hours.
More advanced implants allow for improved joint function. However, in the rush to release new devices to keep up with growing demand, manufacturers may put products on the market that are poorly designed. This may lead to device failure and costly revision surgeries. While the benefits of knee replacement are well recognized, complications from the procedure or from implant failure are also well documented.
The American Academy of Orthopedic Surgeons (AAOS) estimates serious complications requiring additional hospitalization or resulting in life-threatening conditions occur in less than 2 percent of all knee replacement surgeries.
Medicare found higher rates among patients it covers. The federal program tracks treatment of its patients 65 and older who have knee replacement surgery and had found that about 5 percent of its patients who receive knee implants develop complications requiring a return to the hospital within 30 days of surgery.
The risk of complications from knee replacement surgery may be greater depending on a person’s age and overall health. Complications can also be the result of general surgical risks, such as a reaction to anesthesia, or problems that develop after surgery and recovery, such as those caused by a faulty implant. The most serious complications include infection and implant failure.
A 2017 study found a higher complication rate for outpatient knee replacement. Researchers looked at an insurance database for patients who had total knee replacement. The database covered surgeries over an eight year period. About 4,400 people had outpatient knee replacements. Another 129,000 stayed a day or two in the hospital after surgery. Those who had outpatient surgery were 28 percent more likely to experience pain and stiffness.
Infection is a risk of any surgery. It occurs in about one in every 50 knee replacements and needs to be addressed as quickly as possible. Patients are given antibiotics for 24 hours after surgery to reduce the chance of infection.
Implant failure can happen years after surgery. It may involve a defect in an individual implant or a design flaw affecting hundreds or thousands of devices. These problems can lead to the implant breaking or loosening.
It is normal to hear clicking or popping sounds after knee replacement surgery. Most patients experience this with new implants. The noise may be from the metal or plastic parts. Or it may be tendons adjusting to the new implant. The sounds usually decrease or even go away after several months. Patients concerned with clicking should talk to their surgeon. A doctor can tell if the sound is normal or a sign of a complication.
Clicking, by itself, is not a serious problem. But it can be if other conditions happen with it. Patients should let their doctor know if they experience pain along with the clicking. They should also talk with their doctor if swelling accompanies the sounds.
Patients should also let their doctor know if they hear new noises.
When a knee device fails — by not performing as designed — unsuspecting people are subjected to painful complications. Knee device failure can be the result of a patient being obese or performing excessive high-impact activities.
Sometimes, the device fails because of the manufacturer’s faulty design. The Food and Drug Administration’s 510(k) premarket program allows manufacturers to release knee implants without testing as long as they are similar to products already on the market.
Unfortunately, many patients and their doctors are unaware of device problems until after they have already been implanted. Complications resulting from a device are tracked by the FDA and labeled as “adverse events.” These complications often result in the need for a second operation, known as revision surgery, to fix or replace the problematic device.
If there are multiple reports of the same problem with a particular model of implant or one of its components, manufacturers will sometimes recall the device. Consumer Union found that between 2003 and 2013, the six largest manufacturers of knee implants issued a total of 709 recalls for their devices.
Loosening is one of the most common complications resulting from a faulty device. This occurs when components of an implant begin to separate from the bone. Soft tissue instead of bone can grow between the components and the bones, creating instability and pain in the joint. Loosening is natural over time, but it usually does not occur for several years. In poorly designed devices, it can occur in a year or less. Infection can also lead to an implant loosing.
Some manufacturers like Zimmer (now Zimmer-Biomet) have blamed device failure on surgeons, despite the fact that one of its NexGen knee implant models showed higher than normal loosening rates – as many as 36 percent of the devices showed loosening within two years. Thousands of people have had Zimmer’s NexGen Knee models implanted since 2002. According to the FDA, there have been hundreds of adverse events resulting from Zimmer’s devices.
Zimmer’s NexGen CR-Flex uncemented knee was designed to encourage the patient’s bone to grow and naturally fuse with the device. Instead, in just a year, the components can loosen and cause a patient severe discomfort and pain.
Not all knee implant complications occur as a result of defective devices. One of the most serious complications of knee replacement surgery is infection.
Fortunately, the chance of having an infected knee prosthesis is relatively low. About 14,000 cases a year — or roughly 2 percent — can lead to painful infections, according to the nonprofit organization Consumer Reports. These infections can be incredibly costly and difficult to treat, and a patient may experience more pain and be more disabled than they were before the original (primary) knee replacement surgery as a result.
Diabetes or rheumatoid arthritis can increase a patient’s risk of infection. Researchers believe this may be due to how the conditions affect their immune systems.
The chance of developing an infection after a knee replacement can vary significantly depending on the hospital where the surgery takes place, according to Doris Peter, director of the Consumer Reports Health Ratings Center. The center found striking differences regarding the amount of reported knee replacement infections among hospitals in the same area.
Additionally, people who undergo revision surgery have a higher risk of developing an infection.
Typically, when a microorganism enters a part of the body, the body’s defenses can travel to the site through the blood supply and any medicines can also circulate through the blood to kill bacteria.
Because the knee implant does not have its own blood supply, it is easier for microorganisms to attach to the device and infect surrounding tissues. The surfaces of the implant components are ideal for organisms to adhere to and multiply. Once they multiply, they create a film that acts like a biological shield and protects them from antibiotics.
Although rare, the risk of infection continues for as long as the prosthesis remains in the body. Prosthetic joint infections are classified into three types based on the amount of time that has elapsed from the surgery to the onset of infection.
Doctors test for infections using blood tests, radiology tests, blood cultures and joint aspirations (removing fluid from a joint). The type of bacteria that is present in the infection is tested by culturing the sample in a lab.
Most treatment strategies for infected knee joints are a combination of surgical procedures and antibiotic therapy. In severe cases, amputation, joint fusion or removal and a two-stage revision surgery may be necessary.
Patients who are not candidates for a second surgery are usually treated with long-term antibiotics to prevent infection. Two-stage revision surgeries have good results in treating infections, though they can be extremely taxing on the body.
In very rare cases, the infection cannot be treated by revision surgery or antibiotics and reoccurs. Doctors may be forced to amputate a limb in these instances.
However, a procedure called intramedullary arthrodesis of the knee may prevent such a drastic measure. In this procedure, the femur and tibia are fused together by inserting a metal rod into the bones. While the patient avoids amputation, there is significant loss of motion and possible shortening of the leg.
Complications from knee replacements can arise from three different areas: risks that are common to all types of surgery, problems that arise after surgery – even years later – and from the particular circumstances of an individual patient’s knee replacement procedure.
A patient’s individual health, age or physiology can affect his or her particular risk of complications. Osteoporosis or other bone conditions may increase the risk for fractures or problems with bones adhering to the implant. An analysis of patient records also found those patients over 70, those with BMI of 30 or more and patients with a pre-existing pulmonary disorder were at greater risk of various complications.
Difficulty during surgery also may lead to unintended damage to nerves, arteries or ligaments.
The most common complications based on individual surgeries include broken bones, damaged nerves, arteries and ligaments, and an individual’s allergic or immune reactions to the implant’s components.
Any type of surgery can be traumatic to the body and poses general complications. A 2015 study by Harvard University researchers found about 6 percent of general surgery patients had to be readmitted to the hospital following their procedure.
Although infection is the leading general surgery complication, other complications can include reaction to anesthesia, life-threatening blood clots, and rarely, heart or cardiovascular complications.
Death due to a reaction to anesthesia is extremely rare – less than 1 in 100,000 patients die from a reaction to anesthesia.
In the most serious reactions, cognitive dysfunction or memory loss may affect as many as 12 percent of patients over 60. People with heart or lung disease, Alzheimer’s, Parkinson’s or who have had a stroke are at greatest risk of permanent memory loss.
Delirium or confusion upon waking up from anesthesia can affect up to 70 percent of people 60 or older. It may recur but usually clears up in a week.
Blood clotting is a natural healing process in the body and surgery can trigger a clotting response. In some cases, blood clots can pose a serious health problem. Clots forming in the lower legs can cause a condition called deep vein thrombosis (DVT). If these clots break free, they can travel to the lungs and cause a life-threatening condition called a pulmonary embolism (PE).
An analysis of Medicare and private insurance records found DVT occurs in fewer than 3 percent of surgical patients in the hospital, and fewer than 4 percent of patients within 90 days of surgery. But it is estimated that as many as 50 to 70 percent of knee replacement patients may develop DVT without showing any symptoms. Other studies have found that older patients are at greater risk of DVT and death following knee replacement surgery.
Hematomas occur when blood leaks and collects under the skin. This may resolve on its own, but if it does not, minor surgery may be required to remove the blood. Aspirin or antibiotics can increase the risk of hematomas. A fluid buildup called a “Baker’s Cyst” can form behind the knee that may require draining with a needle.
Sutures are usually removed after two weeks, but may be delayed by slow healing. Damage to the skin around the wound may also require a skin graft in rare cases.
Strokes are extremely rare following surgery. Patients with kidney or blood pressure conditions are more likely to experience a stroke. Blood thinners can reduce the likelihood.
Hyperglycemia is an excess of glucose in the blood and is usually associated with diabetes. Paradoxically, people without diabetes are more likely than those with the condition to experience high blood sugar after surgery. Researchers have found hyperglycemia following surgery may be a reaction to infection at the surgical site. Overall, high blood sugar is a rare complication.
The need for blood transfusions during knee replacement surgery is rare, and allergies to blood transfusions are rare among those patients who require them. Among the people most at risk of needing a transfusion during or after surgery are patients who have anemia. Preparation in the days and weeks ahead of the procedure can reduce the chances for a transfusion. Allergies can happen even if the blood type matches the patient’s. Blood allergies usually present as itching and hives and can be treated in most cases with antihistamines.
Some complications that occur during knee replacement surgery may not show up until after the procedure. These can begin while the patient is recovering in the hospital while other complications can take years to occur.
A 2015 review of more than 1.5 million patients – insured through Medicare or private insurers – found 4.5 percent of knee replacement patients under the age of 65 suffered complications while hospitalized. The rate doubled for people 65 and older. About 1 percent reported infections and fewer than 2 percent experienced blood clots as the most common complication during hospital recovery.
In addition to general post-surgery complications, there are several that are specific to knee replacements. In addition to implant failure, these can include joint stiffness, issues with the kneecap, skin conditions, pain and fractures near the implant.
Revision surgery to replace a previously implanted artificial knee includes all the same risks of complications as the primary surgery – and the chances of complications increase. At the same time, revision surgery is more complicated than the original procedure and is not expected to last as long as the original replacement. Hospital stays for patients are also longer for revision surgeries.
Analysis of data from Medicare shows that the average rate of revision surgery within 90 days is 0.2 percent. However, the rate increases to approximately 3.7 percent within 18 months. Surgeons perform about 54,000 revision surgeries for knee implants every year in the U.S., about half happen within two years of the primary surgery.
The most common reason for revision surgery in the short term is to address an infection. In the long term, revision surgery may be necessary to correct complications including dislocations, fractures, pain, joint stiffness, loosening of the device or some other device failure.
About 1 in 50 knee replacement patients may require revision surgery five years after their primary surgery. The rate is about 12 percent after 10 years. The chance of needing revision surgery also increases with the patient’s age.
The risk of death from knee replacement is very low, but it does occur. The 30-day mortality rate for a total knee replacement is about 1 in 400 or 0.25 percent, according to the American Academy of Orthopaedic Surgeons.
In a 2012 study published in The Bone & Joint Journal, researchers in the U.K. analyzed nearly 2,500 people who underwent total knee replacement over a 10-year span, with predicted life expectancy based on age and gender factored in.
The study found that mortality rates were the highest in the 30 to 90 days following surgery, with 99 percent of patients surviving at least one year, 90 percent surviving at least five years and 84 percent still living after 10 years.
Improvements in surgical techniques and growing experience among surgeons have been lowering the risk of death as more knee replacements are performed. A 2014 study in the British journal The Lancet looked at more than 467,000 primary knee replacement outcomes over an eight year period in the UK and concluded post-operative death rates had “fallen substantially.”
Please seek the advice of a medical professional before making health care decisions.
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