Knee replacement surgery is a routine procedure offered to patients with severe knee pain due to osteoarthritis. A total knee replacement involves removing the entire knee joint and replacing it with a prosthetic implant, whereas a partial knee replacement entails replacing only the damaged sections of the knee joint and leaving the undamaged sections intact.
Over time, prosthetic implants wear out and need to be replaced. This is because the implant may have become loose or infected, or the patient may be experiencing pain and instability within the joint.
What is a revision knee replacement?
A revision knee replacement is a surgical procedure to remove a damaged implant and replace it with a new one. As orthopaedic surgeons we are keen to delay the need for revision knee replacement surgery for as long as possible as it is a more complicated procedure than an initial knee replacement and recovery can take longer.
A revision knee replacement has a shorter lifespan than the original knee replacement surgery – generally only around 10 years. This is because there is accumulated trauma and scar tissue leading to diminished performance of the implant.
When the surgeon removes the original prosthesis there is less bone remaining to fix the new implant to and the patient may need a bone graft to support it and encourage new bone growth. The procedure takes longer than primary knee replacement surgery and involves greater pre-operative planning and specialise tools.
A recent study carried out by the Musculoskeletal Research Unit at the Bristol Medical School – in conjunction with the Department of Trauma and Orthopaedics at Torbay and South Devon NHS Foundation Trust, the Health and Policy Research Group at the University of Exeter and the National Institute for Health Research at the Bristol Biomedical Research Centre – looked at how long knee replacements last.
The research team considered 15-year plus survival rates of total and partial knee replacements in patients with osteoarthritis. They reviewed national joint replacement registry reports and extracted the relevant data.
Findings were based on a review of 6490 total hip replacements and 742 partial hip replacements.
The study concluded that 82% of total knee replacements and 70% of partial knee replacements lasted for 25 years.
This is an encouraging statistic as for many older patients the implant will last for the remainder of their natural life.
Signs that you might need revision knee replacement
If you have recently undergone knee replacement surgery, there is a small risk of developing an infection within the implant. Your surgeon will advise you to be vigilant for any unusual swelling, tenderness or fluid leakage. If you notice any of these, you should contact your orthopaedic surgeon immediately who will arrange for a CT or MRI scan to assess what is going on within the joint. You may also need an aspiration procedure to remove fluid from around the joint which is sent to the lab to check for infection.
Over a longer period of time you may experience something called aseptic loosening which is where the bond between the bone and the implant breaks down leading to osteolysis or bone weakening.
Preventing the need for revision knee replacement
If you have undergone knee replacement surgery, your surgeon will advise you how to protect your new joint and reduce the risk of needing revision knee replacement surgery.
Immediately after surgery you will be encouraged to stand and walk as soon as possible and to rehabilitate fully with a programme of exercises to build strength and flexibility.
In the medium to long term, maintaining a healthy weight and avoiding activities that place undue stress on the joint, such as high impact activities like running, jumping or fast court sports, can all help to support your new knee.
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For more information about knee replacements and revision knee replacements, contact us.