Knee Replacements

What Is a Knee Replacement?

Knee replacements involve the surgical removal of a malfunctioning knee joint and replacement with an artificial, engineered joint. The procedure dates back over a century but was modernized in late 1968. Today’s knee replacement recipient tends to be younger and more active, demanding advanced technology.

Why Are Knee Replacements Necessary?

The knee is one of the first joints to wear out in the human body.  This tendency has been complicated by environmental factors in our lives today.  Obesity and inflammatory diseases contribute to the need for knee replacement, which, coupled with longer lifespans, have led to the development of knee replacement devices. An estimated 700 thousand patients receive knee replacement surgery each year in the US and the number increases each year. The American Academy of Orthopaedic Surgeons has estimated by the year 2030, that yearly knee replacement procedures may top 3.5 million.

When Are Knee Replacements Needed?

Knee replacements are required due to an injured joint or one that has simply “worn out.”  Conditions such as arthritis and developmental abnormalities may cause the need for a knee replacement, but injuries and acute medical conditions also contribute.  Knee replacement surgeries are recommended when pain and lack of mobility interfere with normal daily activities.

How Does Knee Replacement Surgery Work?

Knee replacement procedures can be done as a total knee replacement involves all three compartments, the medial compartment (inner knee), the lateral compartment (outer knee), and the patellofemoral compartment (front of the knee) where the entire joint is removed from the top of the larger lower leg bones (tibia) to the bottom of the top leg bone (femur).  Partial knee replacement will involve only one of the three compartments, generally the medial or lateral compartment.  The type of knee replacement surgery will vary from patient to patient based on the severity of joint degradation.

How Do Knee Replacements Help People?

Knee replacements have improved the quality of life for millions of patients, however, some patients ultimately experience more harm than benefit.  Like many other joint replacement procedures, knee replacements use medical devices that are frequently found to be defective resulting in complications that create severe adverse events and may require revision surgery.

What Are the Components of a Knee Replacement?

Knee replacement devices are constructed of three different components. A total knee replacement will use a system that requires all of the components, whereas a partial knee replacement may use only one of two. Some knee replacement systems require the use of cement to stabilize the implants while other systems are designed to allow the bone to grow into the implant to provide stability. Cement-less procedures are used more often on younger patients but are more likely to become detached.

What Is the Femoral Component?

The femoral component of a knee replacement is a metal piece attaches to the end of the femur which has been removed. It is constructed with a center groove that allows the patellar component to slide freely as the knee is bent and straightened.

What Is the Tibial Component?

The tibial component of a knee replacement is a flat, metal, and plastic (polyethylene) part that is cemented or attached to the tibia. The metal portion sits atop the tibia and has a metal rod or stem that is inserted into the bone to stabilize it. The tibial spacer is made of high-density plastic and cushions the knee joint between the tibial component and the femur or femoral component.

What Is the Patellar Component?

The patellar component of a knee replacement covers the underside of the knee cap or patella. It is constructed of plastic and is shaped to match the patella. As it must be nestled and rest correctly within the joint, placement and alignment are critical, in order for the joint to function correctly.

What Kinds of Knee Replacement Systems Are There?

There are several different types of knee replacement systems.  The patient and physician will work together to decide on a type of system that is best for the individual patient.

What Is a Fixed Bearing Knee Replacement?

Fixed-bearing knee replacement devices are best suited for patients who are not as active but are not overweight.  They are not as strong as some other implants and do not allow for as much mobility.  They have been used for a longer period of time than other systems.

What Is a Mobile Bearing Knee Replacement?

A mobile-bearing knee replacement can use either a rotating platform or a medial pivot. Mobile bearing and rotating platform implants provide some flexibility by allowing the tibial component plastic cushion to rotate. This gives greater flexibility on the sides of the knee and is used in young and active patients. Mobile bearing, medial pivot rotates and flexes like the natural knee joint and is also used for younger, more active patients.

What Is a Posterior Cruciate Knee Replacement?

A posterior cruciate knee replacement can either retain or substitute for the ligaments in the knee. The posterior cruciate ligament retaining implant keeps the posterior cruciate ligament intact and is less invasive but not appropriate if the ligament has been damaged. The posterior cruciate ligament substituting implant replaces the ligament with a plastic component. It is used for patients with damaged or weak ligaments and is often used in revision surgeries.

What Is a Gender-Specific Knee Replacement?

Gender-specific implants are designed for women whose physiology may differ from implant systems that are traditionally modeled on male anatomy.

What Knee Replacement Complications Are There?

Despite the design of knee replacement systems intended to improve mobility and the quality of life in patients who receive them, many knee replacement implants have created serious adverse events.  In most of these patients, a knee implant revision surgery will be required which is much more costly and invasive.  Knee revision surgeries are more difficult to perform, may require extensive reconstruction, and may require a significantly longer period of recovery.

What Mild Knee Replacement Complications Can Occur?

Knee replacement surgery complications can include mild or common effects such as:

• Pain, bruising, and swelling of the knee
• Stiffness of the knee which may or may not resolve

How Can a Knee Replacement Cause Knee Stiffness?

Some patients may experience knee stiffness as a knee replacement complication. Knee stiffness may develop from trauma and tissue damage caused during the knee replacement procedure. Patients may completely recover from knee stiffness after healing time and physical therapy. However, some patients experience permanent knee stiffness. In these cases, the patient’s range of motion and overall mobility is typically limited.

What Serious Knee Replacement Complications Can Occur?

More severe complications from knee replacement may include serious and possibly life-threatening effects such as:

• Persistent or increasing knee pain
• Infection with fever or chills
• Blood clots creating pain in the lower leg
• Nerve and blood vessel damage which may be permanent
• Knee replacement failure resulting in dislocation and severe pain
• Periprosthetic fractures in the bone surrounding the implant
• Particle shedding from device structure that is deposited into surrounding tissue
• Osteolysis or necrosis (bone dissolution or tissue death) caused by shed particles

How Can a Knee Replacement Cause an Infection?

Knee replacement infections can range from minor to severe. Typically, medical professionals sterilize the knee before the operation and use sterile equipment and practices during the procedure. However, the open wound can still trap bacteria. Patients with a knee replacement infection may experience fever. Tenderness, redness, and swelling around the infection site are also common.

How Can a Knee Replacement Cause Blood Clots?

Blood clots are a potential knee replacement complication. Blood clots occur when blood cells and other substances form clumps that can block the patient’s blood vessels. During knee replacement surgery, the blood around the knee may become stagnant or move slowly. This is a common cause of knee replacement complications such as blood clots. Blood thinners or special stockings may help the patient’s blood move faster. These treatments can be used during and after surgery.

How Can a Knee Replacement Cause Nerve and Blood Vessel Damage?

Due to the invasive nature of the operation, knee replacement complications can cause nerve and blood vessel damage. There are several nerves and blood vessels near the joint of the knee. Nerve and blood vessel damage may occur as a result of surgeon error. Patients with nerve or blood vessel damage may experience numbness, difficulty moving their lower leg, or excessive bleeding. In most cases, the damage resolves over time and full function is regained.

How Can a Knee Replacement Fail?

Knee replacement complications can cause the device to loosen or fail completely. Loose devices may cause severe pain in the patient’s knee. Research indicates that specific models are more likely to face knee replacement complications. In 2007, the Journal of Bone and Joint Surgery conducted a study showing that roughly 38 percent of Zimmer NexGen LPS-Flex knee replacements loosened within two years. The study also showed that roughly 56 percent of the patients involved required revision surgery due to knee pain.

How Can You Avoid Knee Replacement Complications?

While some knee replacement complications are unavoidable, patients can take steps to reduce the risk. Patients are encouraged to stay active without placing excess stress on the knee replacement. It is recommended that patients follow an aftercare regimen after a knee replacement procedure.

Patients may help to avoid knee replacement complications by:

• Taking the right pain management medication
• Following a healthy, nutritionally diverse diet
• Getting adequate amounts of exercise and rest
• Enrolling in post-operative physical therapy for at least three months

What Is Knee Replacement Revision Surgery?

A knee replacement procedure is designed to last for more than 20 years but up to 90 percent of patients will require a second surgery between 10 and 20 years after the original implant.  Nearly 70 thousand knee revision surgeries are performed each year and unfortunately, some of those procedures are required within a few years of the original surgery.  This is considered an adverse event related to the implant itself.

Revision surgery carries a greater risk for the patient.  It is generally more complicated for the surgeon to perform and may require reconstructive procedures.  It is a more invasive and more costly procedure and typically requires a much longer period of recovery and rehabilitation.

Premature implant failure (within a few years of the implant) has resulted in thousands of lawsuits filed against manufacturers of certain implant devices.

When Is Revision Surgery Necessary?

There are several complications that can lead to revision surgery. Knee replacement revision surgery can be used to replace a failed knee replacement device. Additionally, knee replacement revision surgery can be used to correct injury caused to the knee from the side effects of the device. Patients who require knee replacement revision surgery typically experience a similar list of symptoms. These symptoms include pain, swelling, stiffness, tenderness, and mobility problems.

How Do Loosening and Wear Occur?

The method of fixation plays a large role in whether or not an implant loosens. Fixation can be achieved using cement to attach the implant and the bone. Some surgeons prefer to use non-cemented, or biologic, fixation processes. Over time, friction can compromise the integrity of the fixation.

This friction creates small particles of debris that collect around the knee joint. During aseptic, or non-infected, loosening, the fixation bond is destroyed due to the body’s attempt to break down and digest the debris. The patient’s bone may also be digested during this process. This condition is known as osteolysis.

How Does Infection Occur?

In rare cases, the plastic or metal material of the knee replacement can allow a surface for bacteria to attach. These surfaces are inaccessible by antibiotics, which can lead to severe infection. The implant may loosen as a result of this. Even if the implant remains intact, the patient may experience infection symptoms that lead to knee replacement revision surgery. These symptoms include pain, swelling, and fluid collection.

How Do Fractures Occur?

Patients may experience peri-prosthetic fractures or fractures that occur around the implant site. These fractures often interfere with the stability of the fixation of the implant. If this occurs, the patient will typically require knee replacement revision surgery.

What Is the Revision Surgery Process?

Knee replacement revision surgery typically takes longer than the original knee replacement procedure. In many cases, knee replacement revision surgery takes roughly two to three hours. After the old components of a replacement device are removed, the surgery area is prepared for the revision implant. Implants for revision surgery are different from the original, or “primary,” surgery implants. There are longer and thicker stems for extra support. Any damaged bone in the area must be removed and damage is usually extensive.

When Are Bone Grafts Needed?

If the patient has lost a significant amount of bone, bone grafting may be used to fill the voids. Bone grafts may be autografts or allografts. Autografts use bone from another part of the patient’s body. Allografts obtain bone tissue from an individual who has donated to a bone bank. Wires, metal wedges, or screws can be used to provide additional strength to the bone.

How Does Revision Surgery Treat an Infection?

If knee replacement revision surgery was required to treat infection, other steps are typically taken. This may result in two separate knee replacement revision surgery procedures. In the first operation, the old device is removed. The surgeon implants a cement block that contains antibiotics. This is called an antibiotic-impregnated cement spacer. In another operation, a new knee replacement device is implanted. Intravenous antibiotics are typically administered to eliminate the infection.

What Are the FDA Approval Pathways for Knee Replacements?

Medical devices are classified by the Food and Drug Administration (FDA) into three categories.  Joint replacement devices, including knee replacement implants, are in the Class III division which indicates a significant risk to the patient.  Class III devices generally require a Premarket Approval (PMA) application in order to offer the device for use in the US.  The PMA process requires lengthy and costly clinical studies to be performed in humans to prove efficacy and safety, however, several knee replacement devices have been approved using a shorter pathway.

The FDA’s alternative pathway, known as 510(k) is generally used only for Class I and II devices. An exemption is occasionally allowed for a Class III device if the manufacturer can claim that the device is substantially similar to and not substantially different from products that are already approved for use.

This pathway is intended for upgrades and minor manufacturing improvements, however, the FDA has allowed several knee implant devices to be approved using this pathway.  This has meant that multiple devices have entered the US market without being subjected to clinical studies which would potentially have identified an increased risk of adverse events.

Which Knee Replacement Manufacturers Are Facing Recalls?

There are numerous companies that manufacture knee and other joint replacement devices that are facing recall.  Several of these manufacturers are facing thousands of lawsuits regarding high failure rates and other issues with their products. In addition, four of the largest knee implant manufacturing companies settled with the US government in 2007 regarding claims that they paid surgeons to use their implants. The manufacturers (Zimmer Holdings, DePuy Orthopaedics, Smith & Nephew, and Biomet) agreed to pay $310 million in penalties for the investigation. Another manufacturer, Stryker Orthopaedics, agreed to 18 months of federal supervision instead of a fine.

Who Is Exactech?

Exactech is a medical device company specializing in joint replacements. The company was founded in 1985 by surgeons Dr. Petty and Dr. Miller. The intention behind starting their own business was to start a company that would make a difference in the care quality that doctors would be able to provide for patients. The founders of Exactech believed that they could do this by designing joint replacement technologies through the eyes of a surgeon. This perspective didn’t prevent a recall of certain Exactech knee and ankle replacement devices, however.

Which Exactech Knee Replacement Products Are Facing Recall?

Exactech has recalled the following knee and ankle replacement devices:

• OPTETRAK® Unicondylar Tibial Components
• OPTETRAK® All-polyethylene PS Tibial Components
• OPTETRAK® All-polyethylene CR Tibial Components
• OPTETRAK® PS Tibial Inserts
• OPTETRAK® CR Tibial Inserts
• OPTETRAK® CC Tibial Inserts
• OPTETRAK® CR Slope Tibial Inserts
• OPTETRAK® B-Series PS Tibial Insert
• OPTETRAK® HI-FLEX® PS Tibial Inserts
• CUSTOM OPTETRAK® CC Tibial Insert
• CUSTOM OPTETRAK® Angled PS Insert
• OPTETRAK “MOMB” Non-Mod Molded Insert
• OPTETRAK® RBK PS Tibial Components
• OPTETRAK Logic® PS Tibial Inserts
• OPTETRAK Logic® PSC Tibial Inserts
• OPTETRAK Logic® CC Tibial Inserts
• OPTETRAK Logic® CR Tibial Inserts
• OPTETRAK Logic® CRC Tibial Inserts
• OPTETRAK Logic® CR Slope Tibial Inserts
• TRULIANT® PS Tibial Inserts
• TRULIANT® PSC Tibial Inserts
• TRULIANT® CR Tibial Inserts
• TRULIANT® CRC Tibial Inserts
• TRULIANT® CR Slope Tibial Inserts
• VANTAGE® Fixed-Bearing Liner Component

Exactech has provided a phone number (888) 892-5635 for patients who have a recalled knee or ankle replacement to call for questions and another phone number (888) 912-0403 so that patients can begin the process of making a claim. In order to start a claim with Exactech, you’ll need to have the serial number of the joint replacement device, the name of the surgeon who performed the surgery, and the date the surgery occurred, after which you would be assigned a claim number.

Who Is Zimmer Biomet?

Zimmer Biomet is the second-largest orthopedics company in the US following the completion of Zimmer’s acquisition of Biomet in 2015.  Zimmer Biomet manufactures NexGen knee replacement devices. Several of the NexGen device components have been recalled due to a high incidence of failure. Another product, not part of the NexGen line, the Natural-Knee II Durasel Patella was originally manufactured by Sulzer Medica and acquired by Zimmer Biomet, also faces a recall.

Which Zimmer Biomet Knee Replacement Products Are Facing Recall?

Products facing recall and lawsuits include:

• NexGen MIS Tibial Components
• NexGen TM Tibial Trays
• NexGen LPS-Flex GSF Femoral Component
• NexGen MIS Modular Tibial Plates and Keels
• Natural-Knee II Durasel Patella
• Vanguard PS Open Box Femoral Component
• Vanguard DCM PS Plus Tibial Bearing Implant
• Vanguard CR
• Biomet Surgical instruments

Zimmer Biomet recalled the MIS Tibial component in 2010 due to a locking mechanism failure.  Sulzer Medica had previously paid $1 billion to settle lawsuits regarding other implants. Zimmer Biomet is currently facing over one thousand lawsuits regarding failed knee implants.  Over 1000 of these lawsuits regarding the NexGen devices have been consolidated in multidistrict litigation (MDL) in the State of Illinois. Zimmer Biomet had issued several recalls regarding its components and surgical supplies due to improper labeling and improper assembly.  The Vanguard CR system may be facing multiple lawsuits regarding implant failure.

Who Is DePuy Orthopaedics?

DePuy Orthopaedics – a division of Johnson & Johnson, the largest medical and pharmaceutical products company in the world, developed a range of High-Flex knee implants.  Several of the implant components have been recalled since 2008.  The FDA has also warned DePuy in 2010 regarding accusations of marketing without approval, though one of these systems was subsequently approved and others were removed from the market.

Which DePuy Knee Replacement Products Are Facing Recall?

Products that have faced recall, penalties, and lawsuits include:

• TruMatch Personalized Solutions
• PFC Sigma Knee System with titanium components
• PFC Sigma Knee System components size 2.5, 7 and 8
• PFC Sigma Knee System 30mm – 40mm thick inserts
• Femoral heads that include a 14/16 taper
• Femoral heads with offsets greater than +12
• LPS Diaphyseal Sleeve
• LCS Duofix Femoral Component

All of these DePuy products have faced FDA scrutiny, warnings, or recalls and DePuy faces multiple lawsuits regarding several products.

Who Is Smith & Nephew?

Smith & Nephew has recalled several of its knee replacement devices due to higher-than-normal failure rates including inaccurate labeling issues regarding higher-than-specified iron contents in the metal used for construction.

Which Smith & Nephew Knee Replacement Products Are Facing Recall?

Products that have faced recall include:

• Journey Uni Tibial Baseplate
• Oxinium Genesis II and Profix II

At least three recalls regarding knee implant components have been made by Smith & Nephew since 2003.

Who Is Stryker?

Stryker has been forced to recall a number of products including knee replacement device systems, components, and surgical aids.

Which Stryker Knee Replacement Products Are Facing Recall?

Products that have faced recall and warnings include:

• ShapeMatch Cutting Guide
• Duracon Total Knee
• Unicompartmental Knee System
• Scorpio PS and CR components

Stryker has also received FDA warning letters regarding some products.

What Is the FDA Recall Process?

Medical devices like knee replacement products can generally be recalled in three different ways. A manufacturer may voluntarily recall a product when evidence is showing that it may be harmful to patients. The U.S. Food and Drug Administration (FDA) may request that a manufacturer issue a recall based on adverse event reports and in more severe cases, or in cases where a manufacturer has not cooperated with a request, the FDA may issue a mandatory recall.

If a recall has not been issued as requested, the FDA may take further legal action and may seize defective products as needed. In most cases, manufacturers will issue a voluntary recall or comply with a jointly requested recall.

In the case of most knee replacement recalls that have been issued, products were voluntarily recalled or recalled in compliance with FDA concerns. Knee products have been recalled due to high numbers of adverse events or known problems that emerged in patients who had received the devices.

Why Have Knee Replacement Devices Been Recalled?

Common causes of knee replacement recalls include:

• Device loosening
• Infection
• Persistent and/or severe pain
• Swelling
• Damage to the bone, muscle, and nerves near the device

In many cases, patients who experience serious complications, severe side effects, or device failure must undergo knee replacement revision surgery. These surgeries are performed to fix or replace a faulty or broken device. In most cases, revision surgery will be more complex and require a longer recovery period than the original surgery. In addition, some patients may be required to undergo additional surgeries to reconstruct damaged joint tissue or repair bones that have fractured due to device failure.

What Knee Replacement Lawsuits Are There?

Knee replacement lawsuits have been filed due to a number of complications. Some of these complications lead to the overall failure of the knee replacement device. In a number of cases, patients are forced to undergo revision surgery to fix problems created by the knee replacement.

Revision surgery is a second surgery during which the knee replacement may be corrected or replaced entirely. Revision surgery is often more difficult to perform than the original surgery. Additionally, patients may experience longer recovery times in addition to added physical and financial stress.

Complications leading to knee replacement lawsuits may include:

• Severe pain
• Infection, inflammation, or swelling of the knee
• Damage to the joint, bone, muscle, or nerves
• Loosening of the knee replacement device
• Popping, clicking, or crunching noises
• Mobility issues such as standing or walking

What Exactech Knee Replacement Lawsuits Are There?

Knee replacement lawsuits against Exactech have been filed as recently as May 2022. The plaintiffs have claimed that a catastrophic failure of an Exactech knee replacement device caused injuries that resulted in bone and tissue loss around the location of the knee replacement, resulting in the need for revision surgery and a risk of an above-the-knee amputation in the future.

Plaintiffs claim that Exactech didn’t recall faulty knee replacement devices quickly enough, marketing the Optetrak knee replacement device despite knowing that the polyethylene insert was faulty until the recall in 2021. Multiple patients experienced deterioration of the polyethylene insert that caused pain and limited mobility before failing and causing injury. Some patients had to have revision surgery after only about 5 or 6 years, which is uncommonly soon for a knee replacement.

What Zimmer Biomet Knee Replacement Lawsuits Are There?

Zimmer currently faces more than 700 lawsuits for its NexGen knee replacement system. Federal cases filed against Zimmer were consolidated into multidistrict litigation (MDL). An MDL is used to streamline the pretrial process for a number of similar cases. The Zimmer MDL was transferred to the U.S. District Court’s Northern District of Illinois. After the pretrial phase is complete, each case will be returned to its respective district.

What Knee Replacement Lawsuits Are There?

There have been many lawsuits filed against manufacturers of knee replacement devices. Some of these lawsuits have now been settled. A high-profile case against Sulzer Medica was settled for a total of $1 billion across a combined 4,000 cases. Other cases have been dismissed. If you were harmed by a faulty knee replacement, it’s important to discuss your situation with an attorney to determine whether you have a case against the manufacturer of your knee replacement.

Notwithstanding claims relating to this product, the drug/medical device remains approved by the U.S. FDA.