Understanding Knee Replacement Surgery
Knee replacement surgery involves removing the damaged portions of the knee joint and replacing them with artificial components made of metal and plastic. The two types of knee replacement surgeries are:
- Total Knee Replacement (TKR): Replacement of all three compartments of the knee joint.
- Partial Knee Replacement (PKR): Replacement of the damaged portion of the knee.
Both procedures are designed to relieve pain, improve function, and allow the patient to do their everyday activities.
Average Life Expectancy of a Knee Replacement
Many studies and orthopaedic associations worldwide have reported that most knee replacements typically last between 15 and 20 years. This is certainly not an absolute timeline. Improvements in the way surgeries are done, the types of materials and the designs of prosthetics are now allowing many implants to last even longer.
Key Statistics:
A 2019 study published in The Lancet found that:
- 82% of total knee replacements lasted 25 years.
- 90% lasted 20 years.
- 95% lasted 10 years.
These numbers indicate that with proper follow-up care, most individuals can expect their knee replacements to function well for decades, and many, if not most, will last the remainder of the patient's life. This is particularly true if the patients are over sixty at the time of surgery.
Factors That Influence Longevity
Several variables can affect the longevity of your knee replacement:
Age at Time of Surgery
Patients younger than 60 are generally more active, and therefore, greater stress is placed on the prosthetic joint. As a result, younger patients may require knee joint replacement again later in life.
Activity Level
Certain high-impact activities, such as running, jumping, and contact sports, have a more accelerated wear on the prosthetic joint. Low-impact activities, such as walking, swimming, or cycling, are recommended.
Body Weight
Excess body weight means extra pressure on the knee joint. Obese patients who undergo joint replacement surgery are at a greater risk of implant failure and complications.
Surgical Technique
The orthopaedic surgeon's training and experience are vital. Proper orientation and placement of the prosthesis can reduce stress on the joint and potentially increase its longevity.
Implant Type
Some newer designs and materials of prostheses (e.g., highly cross-linked polyethene) have improved wear characteristics, which may extend longevity.
Rehabilitation Following Surgery
Following an organised physical therapy routine and the surgeon's instructions are vital to recovery and long-term results.
Signs That a Knee Replacement May Be Wearing Out
Knee replacements are expected to last decades, but they are still subject to potential failure or wear out. Here are some reasons to consider when assessing if there may be an issue:
- Increasing knee discomfort
- Swelling or stiffness
- Instability of feeling that the knee is “giving out”
- Range of motion is diminishing
- Unusual noises, such as clicking or grinding.
If any of these symptoms develop, please see your orthopaedic surgeon for an evaluation.
What Happens If a Knee Replacement Wears Out?
When a knee replacement doesn’t work, you may need a revision knee replacement. This means the old prosthesis must be removed, and a new one put into place. Revision surgeries are more complicated than the primary surgery and may take a longer time to recover. However, much like the first knee replacement, a revision can relieve pain and restore mobility to the patient.
How to Make Your Knee Replacement Last Longer
Here are some proactive measures you can take to maximise the longevity of your knee prosthesis:
Maintain a Healthy Weight
Losing body weight reduces stress on the knee and decreases the possibility of the implant failing.
Stay Active But Wisely
Low-impact exercises will strengthen your muscles and keep your joints flexible, without straining your knees.
Avoid High-Impact Activities
You should not run, jump, or lift heavy objects unless your doctor advises you to do so.
Stick to Your Rehab Program
Rehabilitation is crucial for regaining strength and mobility after surgery. Not participating may be detrimental in the long run.
Use Support If You Need It
Using a cane or walker allows you to offload weight during recovery and shield your implant from trauma while it is healing.
Follow-Up Visits
Following up regularly with your orthopaedic surgeon can help him/her detect early signs of wear and possible complications.
The Future of Knee Replacement Longevity
As technology has progressed, the longevity of knee implants may have also progressed. Advancements in minimally invasive procedures, robotics-assisted surgery, new materials, and biologic healing therapies have had a helpful impact on successful outcomes and, potentially, the long-term retention of knee replacements. Furthermore, some new-generation implants are designed to last 30 years or more.
To Conclude…
Knee replacement surgery has revolutionised orthopaedic care, restoring pain-free mobility to millions of people worldwide. While the typical knee replacement device has a lifespan of 15–20 years, many exceed this, particularly with appropriate health monitoring and lifestyle changes. Identifying what affects the life span of your implant (and how to preserve it) can help you enjoy the benefits for as long as possible.
Whether you are contemplating a knee replacement or have already had one, ask your orthopaedic team what you can do to protect your investment for long-term mobility.