Home › Blog › Identifying the Symptoms of a Loose Knee Replacement

Knee replacements can be an option for someone with severe knee pain and mobility issues. These artificial joints that mimic a natural knee can help restore a person’s ability to do their daily activities. Yet, like any surgical procedure, it comes with the risk of complications. One potential complication is the loosening of the implant.

Overview of Knee Replacement

Knee replacement surgery is also known as total knee arthroplasty. It involves replacing damaged or diseased portions of the knee joint with artificial components. There are two types of knee replacements. They are: 

• Partial knee replacement: In this procedure, only the damaged part of the knee joint is replaced with an implant. This type of procedure is more common in young adults. It is typically only done to address injury or trauma to one area of the knee.
• Total knee replacement: As the name suggests, this procedure involves replacing the entire knee joint. Total knee replacements are the most common type of knee replacement surgery.

The most common reason for a knee replacement is to treat severe osteoarthritis. This condition develops when the protective cartilage between knee bones gradually wears down. This can lead to knee pain and stiffness, making it hard to do everyday activities like walking or climbing stairs. 

Other conditions that may lead to knee replacement include rheumatoid arthritis, post-traumatic arthritis, and knee injuries.

The Cost of Knee Replacement Surgery

The cost of knee replacement surgery can vary significantly. Typically, it can range from $20,000 to $70,000. Contributing factors include:

• Medical insurance or medical benefits: Each person’s plan is different and variables can include out-of-pocket costs, co-pays, and deductibles.
  
• Hospital stay duration:: A patient’s total stay at the hospital after knee replacement can vary depending on the type of replacement, their individual health factors, as well as progress of recovery. 
• How long you spend in the hospital after a knee replacement procedure can vary depending on the type of replacement, individual health factors, and your recovery progress. However, the longer your stay is, the more expensive the total cost will be.
• Type of implant used: Knee implants are typically made of metal alloys and plastic materials. The surgical approach can also vary. Some surgeons use customized instruments or computer technology to assist in the surgery. All of these factors contribute to the total cost.
• Pre Existing conditions: These can affect both the cost and outcome of knee replacement surgery. Individuals with obesity, diabetes, or heart disease may require additional care during and after the procedure, which can result in higher costs.
• Location: The cost of knee replacement surgery varies based on the location. Typically, urban areas tend to have higher costs due to factors such as demand and overhead expenses.

Although knee replacement surgery can improve knee function for patients, these artificial joints are not indestructible. Like any other surgical implant, knee replacements can wear down over time or fail for various reasons.

Factors Contributing to Loosening of Knee Replacement

Several factors can contribute to the loosening of a knee replacement implant. These factors vary in severity depending on the individual case, and can be more common in adults over the age of 45. However, they can occur in any age group.

• Wear: Over time, if the implant has a plastic surface it can wear down. When this occurs, it can lead to particle-induced osteolysis, which is the body’s response to particles of the implant breaking down and causing inflammation. This can eventually lead to loosening of the knee replacement.
• Surgical and implant quality: The surgical technique used and the quality of the implant itself can also contribute to loosening. If the joint is not aligned correctly during surgery or if a low-quality implant is used, it may lead to loosening over time.
• High-impact activities: Participating in high-impact activities like running or contact sports can put excessive pressure on the knee replacement. This can cause the artificial components to wear down at a faster rate.
• Bone weakening: Conditions like osteoporosis or rheumatoid arthritis can weaken the bone around the implant, making it more prone to loosening.
• Infection: In rare cases, an infection can occur around the knee replacement. This can cause inflammation and weakening of the bone. Such an infection can be caused by bacteria entering the body through a wound or during surgery.
• Patient’s body weight: Weight can put added stress on the knee replacement, increasing the risk of loosening.
• Trauma: In rare cases, a traumatic event such as a fall or accident can cause the knee replacement to become loose.
• Implant dislocation: A dislocated implant can cause instability and looseness in the knee joint, leading to complications. This can happen if the joint is not aligned correctly during surgery or due to excessive wear and tear over time or if a patient participates in high-impact activities that put stress on the implant.

7 Common Loosening Knee Replacement Symptoms To Know

If a knee replacement becomes loose, it can cause significant discomfort and limit the ability for knee movement. For some, that can mean difficulty running, jumping, kneeling, or even walking. 

Recognizing the symptoms of a loose knee replacement is vital since early detection can lead to better treatment outcomes. The following are seven common symptoms of a loosening knee replacement to be aware of:

1. Pain Ranging from Mild to Severe

Pain is often the first sign of a loose knee replacement. Such pain can range from mild discomfort to severe and constant pain that interferes with daily activities. The pain may be felt around the knee joint and may also radiate to the thigh or the calf.

2. Swelling and Redness

When a knee replacement becomes loose, the friction and irritation from the loose implant can induce an inflammatory reaction in the nearby tissues, resulting in swelling and redness in the knee joint area. 

In people with darker skin tones, these changes may be more subtle, so it is important to also look for signs such as tenderness, heat, and texture changes.

In some cases, redness may not always be present during inflammation, and its presence alone does not necessarily indicate the presence of inflammation. Swelling and redness can also be caused by an infection, which is another potential cause of a loose knee replacement.

3. Popping or Clicking Sound

Experiencing a popping or clicking sound while walking, could indicate a loose knee replacement. This is caused by the loosening of the implant components, which may rub against each. In some instances, these sounds may also indicate an implant dislocation. If the artificial components become misaligned, they can produce audible noises when moving.

4. Joint Stiffness

Loosening of the implant can cause inflammation and swelling, leading to joint stiffness and a reduced range of motion. Stiffness is often accompanied by pain and discomfort.

5. Skin Discoloration

Sometimes, a loose knee replacement may cause skin discoloration around the affected area. For example, the skin may appear bruised, bluish, or yellowish due to poor circulation caused by inflammation or damage to the surrounding tissues. This discoloration may accompany other symptoms such as warmth, tenderness, or swelling.

6. Instability

A loose knee replacement can cause instability in the affected knee joint, making it difficult to walk or perform daily activities. Instability can also occur if an implant dislocates. In this case, the artificial components may shift out of their proper alignment, causing issues with stability and mobility.

7. Reduced Range of Motion

If the artificial components become misaligned, they may impede the natural movement of the knee joint, leading to a reduced range of motion. This can make it difficult for patients to perform simple activities like bending their knees or walking up and down stairs.

How Medical Specialists Diagnose a Loosened Knee Prosthesis

When experiencing symptoms of a loosened knee prosthesis, seek medical attention. A physician should conduct a thorough physical exam to diagnose the presence of a loose knee implant.

They will ask about previous surgeries on the affected knee and general medical history, conduct a physical exam, and order additional tests like X-rays, MRI, or CT scans to assess the condition of the knee implant and its surrounding tissues.

Is Surgical Intervention Needed to Correct Loosening?

If a loosened prosthesis is diagnosed, your physician may recommend revision total knee replacement, which is a more complex and invasive procedure than the initial knee replacement surgery. 

Revision surgery involves removing the loosened or damaged implant components and replacing them with new ones. It may also include addressing any underlying issues like infection or poor bone quality.

While revision surgery can address a loose knee prosthesis, it carries risks and should be considered carefully. Surgical intervention may not always be the best or only option.

Potential Risks of Revision Surgery

A study shows that 11 to 20.8% of patients who have undergone initial knee replacement surgery experience perioperative complications. 

Revision surgery, like any surgery, carries risks such as infection, poor wound healing, bone fractures, and blood vessel issues. These risks can be higher than those of the initial knee replacement surgery. 

Understanding what the risks are can help someone dealing with knee conditions to make a more informed decision about treatment options. Like any surgical procedure, the revision surgery should be a last resort and only considered after exploring all other possible solutions. 

The following are some potential risks of revision surgery:

Surgical Issues

Revision surgery is an invasive procedure that carries similar and greater risks compared to the initial knee replacement surgery. This is because revision surgery may involve more extensive incisions and bone removal to remove or replace the loosened implant components. 

However, that doesn’t mean it’s not a viable option for treating a loose knee prosthesis. Many factors contribute to the outcome of revision surgery, such as the patient’s overall health and age, and the surgeon’s skill. Keeping this in mind, the following are some surgical complications that may occur:

Infection

Revision surgery presents a higher risk of an infection than the initial knee replacement surgery. Previous surgeries can create scar tissue, making it more challenging to access and clean the affected area. Additionally, revision surgery may involve longer operating times, increasing the risk of infection.

The risk of infection varies based on factors such as the patient’s health, medical history, and the surgeon’s experience. However, not all infections are severe, and most can be treated with antibiotics.

Poor Wound Healing

Poor wound healing refers to the slow or inadequate healing of a surgical incision, which could lead to infection as well as a delayed recovery. Since revision surgery involves reopening an old incision or creating a new one, there is a risk of poor wound healing. This is especially true for patients who are older or have certain health conditions that affect wound healing, such as diabetes. The risk of poor wound healing can be reduced by following proper post-operative care instructions and managing underlying health conditions.

Bone Fracture

During revision surgery, the surgeon might need to remove more bone to access or replace the loosened implant components. Doing so can weaken the remaining bone and increase the risk of a fracture during or after the procedure. Bone fractures can prolong recovery time and may require additional surgeries to fix.

They can also result in long-term complications such as instability or reduced range of motion, thereby decreasing quality of life. The risk of bone fracture may vary based on factors such as the patient’s age and overall health. Younger adults in good health are much less at risk of experiencing a bone fracture during revision surgery.

Blood Vessel Issues

Revision surgery can also put patients at an increased risk of blood vessel issues, such as deep vein thrombosis (DVT) or pulmonary embolism. Deep vein thrombosis (DVT) is a condition where blood clots develop in the leg veins, while pulmonary embolism occurs when these blood clots travel to the lungs. DVT is usually not serious and can be treated with anticoagulant medications. However, pulmonary embolisms are serious and potentially life-threatening complications that can occur after surgery.

During revision knee replacement surgery, there is an increased risk of developing DVT due to the longer operating time and the manipulation of tissues. If a blood clot develops and travels to the lungs, it can cause pulmonary embolism. This can be fatal if left untreated. 

Although the risk of developing DVT or pulmonary embolism after revision knee replacement surgery is relatively low, it should still be taken seriously.

Circulatory Problems

As mentioned earlier, blood clots can form in the legs after revision surgery, increasing the risk of pulmonary embolism. However, other circulatory issues may arise during or after revision knee replacement surgery. For example, patients may experience swelling or leg pain due to disrupted blood flow. This can be managed with medication and physical therapy.

The risk of circulatory issues following revision surgery is relatively low, but medical professionals should still monitor and manage it to prevent serious complications.

Nerve Damage

Due to the extensive manipulation of tissues and bones during revision surgery, there is a risk of nerve damage or injury. This can result in numbness, weakness, and even paralysis, in rare cases. The risk of nerve damage or injury during revision knee replacement surgery is relatively rare. However, this may vary depending on factors such as the patient’s age and underlying health conditions. Additionally, not all nerve damage or injuries are severe and may improve over time.

Improve Mobility Without Surgery If A Knee Replacement Fails

People who are experiencing persistent symptoms of complications after going through knee surgery should seek medical attention and explore all options before considering revision surgery. Regenexx procedures offer a non-surgical approach to managing knee pain using regenerative medicine that can help improve knee function without surgery. 

A Regenexx network physician will use interventional orthopedics to treat the root cause of knee replacement failure. Regenexx procedures can help promote the body’s natural healing abilities, reducing pain and improving function.

Originally published on Sep 5, 2024