How Long Will A Knee Replacement Last

Knee replacement surgery, also known as knee arthroplasty, is a common surgical procedure performed on patients with severe knee pain arthritis and limited mobility caused by severe arthritis, injury, or other conditions. The surgery involves removing the damaged or diseased knee joint and replacing it with an artificial joint made of metal and plastic components. While knee replacement surgery can be highly effective in restoring knee function and relieving pain, patients often wonder how long does a knee replacement last. In this article, we will explore the factors that determine the lifespan of a knee replacement, the different types of knee replacements, and what patients can do to increase the longevity of their artificial knee joints.

What happens during surgery

Preparation for Knee Replacement Surgery

Before the surgery, the patient will undergo several tests to ensure that they are physically and medically fit to undergo the joint replacement. The surgeon will review the patient's medical history and perform a physical examination, including imaging tests such as X-rays, MRI, or CT scans to assess the severity of the knee damage. Blood tests will also be performed to check for any underlying health conditions that could increase the risk of complications during surgery.

The surgeon will discuss the procedure, potential risks and benefits, and alternative treatment options with the patient to help them make an informed decision about the surgery. If the patient decides to proceed with the surgery, they will be given instructions on how to prepare for the procedure, such as stopping certain medications, avoiding food and drink before the knee replacement surgery, and arranging for transportation to and from the hospital.

Anesthesia

Knee replacement surgery is typically performed under general anesthesia, which means the patient will be unconscious during the procedure. In some cases, regional anesthesia, which numbs the lower half of the body, may be used instead. The anesthesiologist will discuss the type of anesthesia to be used with the patient before the surgery.

The Surgery

Once the patient is under anesthesia, the surgeon will make an incision in the knee area to access the knee joint. The length and location of the incision may vary depending on the patient's knee condition and the type of knee replacement being used. Typically, patients will have a traditional incision as seen in the picture below, but there are many other options surgeons perform based on the patients goals and request.

After the incision is made, the surgeon will then remove the damaged parts of the knee joint, including the damaged cartilage and bone, using special surgical instruments. This process involves cutting away the damaged parts of the femur (thigh bone), tibia (shin bone), and patella (kneecap).

After removing the damaged parts, the surgeon will prepare the remaining bones to receive the artificial components. This involves reshaping the surface of the femur and tibia to fit the artificial implants accurately. The surgeon also will perform a patellofemoral replacement to remove the arthritic knee cap. Reshaping the bones and replacing the knee cap will take the longest to complete for the surgeon. Many surgeons also use a robotic assistant to help make perfect cuts. You can read more about that here.

The surgeon will then attach the artificial components to the prepared bone surfaces using a special surgical adhesive or cement. The cement or adhesive will be a crucial part in the longevity of your total knee replacement. The metal knee implants or artificial components typically consist of a metal alloy or ceramic material. Then in between the metal knee parts is a plastic spacer or polyethylene spacer that reduces metal on metal noise and friction. The plastic spacer that acts as a cushion between the two metal components. You can imagine how noisy it would be without the plastic piece!

Once the artificial components are in place, the surgeon will close the incision using surgical staples or sutures. The wound will be covered with a sterile dressing.

Factors that determine the lifespan of a knee replacement

The lifespan of a total knee replacement depends on various factors, including the patient's age, weight, activity level, overall health, and the type of replacement used. Studies show that knee replacements can last anywhere from 10 to 25 years. The success rate of a knee replacement surgery depends on several factors that we will discuss in the following sections:

Patient age and health

Age and overall health are significant factors that can affect the longevity of a knee replacement. Healthier and younger patients tend to have better outcomes and longer-lasting knee replacements than older and less healthy patients. For example, a study published in The Journal of Bone and Joint Surgery found that patients who underwent knee replacement surgery before the age of 65 had a lower risk of requiring revision surgery than patients who underwent surgery after the age of 65. A revision surgery is when the knee is replaced again with a new total knee replacement. Typically, this happens between 10-20 years.

Weight

Weight is another critical factor that can impact the lifespan of a joint replacement. Overweight patients are at a higher risk of implant failure due to increased stress on the knee joint, specifically the plastic spacer (polyethylene spacer) and the cement. In fact, studies have shown that obese patients are up to four times more likely to require revision surgery than patients with a healthy body mass index (BMI). Therefore, maintaining a healthy weight is crucial for the longevity of a knee replacement and all the joints in your body.

Activity level

The activity level of a patient can also affect the lifespan of a knee replacement. Patients who engage in high-impact activities, such as running or jumping, are more likely to experience wear and tear on their artificial knee joint, leading to implant failure. On the other hand, patients who lead a sedentary lifestyle may experience stiffness and reduced mobility in their knee joint, which can also impact the longevity of the implant. Therefore, patients should engage in low-impact activities, such as walking, swimming, or cycling, to maintain their knee function without putting excessive stress on the implant. If you are interested in more information about what activities you should and should not do, please read this article.

Type of knee replacement

The type of knee replacement used can also impact the lifespan of the implant. There are three main types of knee replacements: total knee replacement, partial knee replacement, and bilateral knee replacement. Total knee replacement involves replacing the entire knee joint with an artificial joint, while partial knee replacement involves replacing only the damaged part of the knee joint. Bilateral knee replacement is two total knee replacements completed on both legs.

Studies have shown that partial knee replacement has a higher success rate and a lower risk of requiring revision surgery than total knee replacement. A study published in The Journal of Arthroplasty found that patients who underwent partial knee replacement had a 10-year survival rate of 93%, compared to a 10-year survival rate of 91% for patients who underwent total knee replacement. However, partial knee replacement is only suitable for a select group of patients who have damage limited to one part of the knee joint.

Revision surgery

Revision surgery is a surgical procedure that involves replacing a previously implanted artificial joint with a new one. Revision surgery is typically necessary when the initial implant fails due to wear and tear, infection, or other complications. Revision surgery is more complex than the initial knee replacement surgery and carries a higher risk of complications, such as infection, blood clots, and nerve damage. Additionally, revision surgery has a lower success rate and a higher risk of requiring additional revision surgeries.

A complete revision of this type is a complex procedure that requires extensive preoperative planning, specialized implants and tools, prolonged operating times, and mastery of difficult surgical techniques.

Who needs knee revision surgery? A knee revision may be necessary for anyone whose prosthetic knee implant fails due to injury or wear, or who gets an infection in the area around implant. In elderly people who undergo this knee surgery, the artificial knee implants may last for life. But in younger patients, you may need to get the replaced before you reach age 75.

According to a study published in The Journal of Bone and Joint Surgery, the average lifespan of a knee replacement is approximately 20 years, with 90% of implants lasting at least 10 years and 80% lasting at least 20 years. However, the lifespan of a knee replacement can vary depending on the patient's individual circumstances, such as age, weight, activity level, and the type of knee replacement used.

The Arthritis Foundation notes that advances in implant technology and surgical techniques have improved the lifespan of knee replacements in recent years. Newer implants are designed to be more durable and resist wear and tear, and surgical techniques have become less invasive, reducing the risk of complications and improving patient outcomes. Previous research from the Arthritis Foundation, stated the knee replacements were expected to last 15 years, but now, since the technology of the implants have improved, knee replacements are lasting 25 years - a decade more than expected.

Increasing the lifespan of a knee replacement

Patients can take several steps to increase the lifespan of their knee replacement and reduce the risk of requiring revision surgery. These steps include:

1. Maintaining a healthy weight: As we mentioned earlier, being overweight can increase the stress on the knee joint, leading to implant failure. Therefore, maintaining a healthy weight through a balanced diet and regular exercise can help prolong the lifespan of a knee replacement.

2. Engaging in low-impact activities: Patients should avoid high-impact activities, such as running or jumping, and instead engage in low-impact activities, such as walking, swimming, or cycling. These activities can help maintain knee function without putting excessive stress on the implant.

3. Following the rehabilitation program: Following the rehabilitation program prescribed by the surgeon or physical therapist is essential for restoring knee function and preventing complications. Patients should follow the exercise program and avoid activities that may cause pain or discomfort in the knee joint. If you need assistance with your rehabilitation process, please look into the courses here.

4. Avoiding smoking: Smoking can increase the risk of complications after surgery, such as infection and delayed healing. Therefore, patients should quit smoking before undergoing knee replacement surgery and avoid smoking after surgery to increase the lifespan of their knee replacement.

5. Regular follow-up visits: Patients should schedule regular follow-up visits with their surgeon to monitor the implant's function and detect any potential complications early. Early detection and treatment of complications can help prevent implant failure and the need for revision surgery.
   
   

Physical therapy

Physical therapy is an important component of the recovery process for knee replacement surgery patients. The primary goal of physical therapy is to restore strength, flexibility, and range of motion in the affected joint. Improving strength and moblity of the knee joint can also increase the life of the knee replacement. Physical therapy can also help reduce pain, improve balance, and prevent future injury or joint damage.

For knee replacement surgery patients, physical therapy typically begins soon after surgery, while the patient is still in the hospital or a rehabilitation facility. The first few days after surgery are focused on pain management and gentle range-of-motion exercises. As the patient's condition improves, physical therapy will progress to include more challenging exercises and activities, such as walking, stair climbing, and weight-bearing exercises.

Strengthening the muscles in the legs is essential for knee replacement patients, as it can help improve the function and stability of the joint, reduce pain and inflammation, and increase the lifespan of the implant. The key muscle to strengthen after this joint replacement are the quadriceps muscles. These muscles will act as a shock absorber to your new knee. If you have strong quads, you will have less force on your new knee implant each time you take a step.

Some quadriceps strengthening exercises to try:

Stand up, sit down

Squats (half squats)

Step ups

Lunges (mini lunges)

Straight leg raise

 More exercise ideas in the knee replacement courses,
click here to enroll!

Other tips:

1. Start Slow: It's important to start slowly and gradually build up the intensity and duration of your exercise routine. Avoid overexerting yourself or pushing yourself too hard, as this can lead to injury or setbacks in your recovery.

2. Work with a Physical Therapist: A physical therapist can help you develop a personalized exercise plan based on your specific needs and goals. They can also provide guidance and support throughout the recovery process.

3. Incorporate Low-Impact Exercises: Low-impact exercises, such as walking, cycling, and swimming, are ideal for knee replacement patients. These exercises are gentle on the joints and can help improve strength, flexibility, and cardiovascular fitness.

4. Practice Balance and Stability Exercises: Balance and stability exercises, such as standing on one leg or using a balance board, can help improve the stability and balance of the knee joint, reducing the risk of falls or other injuries.

5. Use Resistance Bands: Resistance bands can be used to add resistance to exercises and help build strength in the leg muscles. Strengthening your muscles will help offload pressure from your knee implant causing less damage overtime. They are easy to use and can be incorporated into a variety of exercises.

    

   
   
   
   Bands available on Amazon -Click here
   
   

Conclusion

In conclusion, knee replacement surgery can be highly effective in restoring knee function and relieving pain in patients with severe knee conditions. The lifespan of a knee replacement depends on various factors, including the patient's age, weight, activity level, overall health, and the type of knee replacement used. While the average lifespan of a knee replacement is approximately 20 years, individual circumstances can impact the lifespan of the implant. Patients can take several steps to increase the lifespan of their knee replacement, such as maintaining a healthy weight, engaging in low-impact activities, following the rehabilitation program, avoiding smoking, and scheduling regular follow-up visits with their surgeon. By taking these steps, patients can maximize the lifespan of their knee replacement and enjoy an active and pain-free life.