Total Knee Replacement
What is a total knee replacement (TKR)?
A total knee replacement (also known as total knee arthroplasty) is an operation performed to replace a worn-out knee joint. The joint becomes worn-out most commonly as a result of osteoarthritis but can also result from other causes such as trauma or injuries, inflammation (eg. rheumatoid arthritis), infection and overuse. The aim of a TKR is to relieve pain, restore function and movement, and improve quality of life.
The diseased joint and bone is removed and replaced with a new artificial knee joint. The artificial knee joint is made from a surgical-grade metal alloy with a special wear resistant plastic insert. TKRs are one of the most successful operations available today with over 90% still functioning well at 15 years.
What are the symptoms of joint damage requiring a knee replacement?
Most patients complain of severe pain in the knee. This pain can be felt deep inside the knee or in the front, sides or back of the knee. There is often associated swelling around the knee. The pain is often made worse with walking. Daily activities such as putting on shoes and socks, going up and down stairs, getting up from chairs, driving and walking around the block or shopping centre become more and more difficult. Occasionally walking aids are required to assist with mobility. Some patients also have the sensation of ‘grating’ or ‘locking’ in the knee and develop pain at night.
How is knee osteoarthritis diagnosed?
A well trained doctor or other para-medical professional will suspect osteoarthritis based on your symptoms and a thorough examination of your knee. A simple x-ray (AP and lateral weight-bearing views) of your knee is often enough to confirm the diagnosis. Occasionally a CT scan with 3D reconstruction or MRI may be required if the diagnosis is unclear with plain x-ray alone. Not all of these tests are required to confirm the diagnosis.
What are the causes of knee osteoarthritis?
Most commonly, osteoarthritis is due to ‘wear and tear’ of the joint as we age. It may also develop secondary to other conditions such as rheumatoid arthritis (or other inflammatory arthritis), meniscal or articular cartilage tears, osteochondritis dissicans (OCD), infection, trauma and fractures.
Is knee osteoarthritis dangerous?
Osteoarthritis is not life threatening but can severely impact your quality of life and function. The activities of daily living, which most take for granted, become increasingly difficult.
What is the treatment for knee osteoarthritis?
In the early stages of osteoarthritis, pain killers, physiotherapy and weight loss are effective. As the knee joint continues to wear out, these modalities becomes less and less so. When the pain becomes severe or when symptoms begin to interfere with your function or lifestyle, the most effective treatment is a TKR. A TKR provides the most reliable and consistent results with respect to pain minimisation and return of function.
If only part of the knee joint is affected by osteoarthritis, it may be possible to do half-knee replacements (also known as uni-compartmental knee replacements or arthroplasty) or osteotomies (re-alignment procedures) rather than a TKR. Your surgeon may discuss these options with you if applicable.
When can I walk after a TKR?
Full weight-bearing and walking is allowed immediately and encouraged after a TKR. Initially this will be aided by crutches but once you regain strength and mobility, crutches can be discarded. The long term results of your knee replacement will depend on how much work you put into your rehabilitation following your operation.
When can I drive after a TKR?
You should not drive for 48 hours after an anaesthetic. After 48 hours, your ability to drive will depend on the side you had your operation, left or right, and the type of vehicle you drive, manual or automatic. If you had a left knee procedure and drive an automatic, you can drive whenever you feel comfortable. Otherwise, it is recommend that you do not drive for 6 weeks.
When can I return to work after a TKR?
Your return to work will vary depending on the type of work you are engaged in. Most people can return to office work within 2-3 weeks. Patients who perform labour intensive work may not be suitable candidates for a TKR.
When can I play after a TKR?
Low impact activities, such as cycling and swimming, can be commenced from week 6. High impact activities such as running are best avoided for 12 weeks after surgery.
How long will I take to heal after a TKR?
The wounds take 7-10 days to heal. Most patients improve dramatically in the first 6 weeks. Occasionally, there are periods where the knee may become sore and then settle again. This is part of the normal healing process. It takes six months for your knee to fully recover from a knee replacement. Continued improvements may be gained up to 1 year post-surgery.
How much pain will I experience after a TKR?
Most patients are pleasantly surprised at how little pain they have after surgery. This is because local anaesthetic is injected around the wound during the procedure and a local anaesthetic catheter is placed in the wound after the procedure to minimise any pain you may experience. You will also be given a “patch” which dispenses pain-killers continually in addition to the usual on-demand pain-killers.
How long will the prosthesis last after a TKR?
Current prostheses have a greater than 90% 15-year survival rate. This means that after 15 years, 1 in 10 patients may require a partial or complete revision of components or may require an exchange of the plastic liner. However, the majority of TKRs (ie. 9 in 10 patients) will still be functioning well.
What are the risks of having a TKR?
This following list is by no means exhaustive, so it is important to discuss your concerns with your your surgeon.
It is quite normal to experience some swelling and discomfort in the knee and leg after surgery. This is expected and will also resolve with time. Some patients occasionally report numbness or tingling in the knee or around the wound. This usually resolves or reduces with time, but occasionally it may be permanent. The altered sensation arises from a specific sensory skin nerve over the knee and does not compromise the TKR, muscles or knee stability or function in any way. Surgical risks specific to knee replacements include: fractures, dislocations, prosthesis loosening, nerve or vascular injury, ligament injury and stiffness.
Other general surgical risks include: risk of infection, bleeding and clots in the leg (DVT) or lung post-operatively.
Apart from surgical risks, medical (including allergies) and anaesthetic complications can occur, and these can affect your general well being and health.
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- Revision Knee Replacement
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