Knee Replacement Surgery (arthroplasty) is a routine operation that involves resurfacing a damaged, worn or diseased cartilage of the knee with an artificial surface.
This surgery is actually a knee resurfacing surgery which is commonly referred as knee replacement surgery but the whole joint is not replaced in this surgery only the damaged part is resurface.
Adults of any age can be considered for a knee replacement, an average mostly are carried out on people between the ages of 60 and 80 years. More people are now receiving this operation at a younger age. A resurfaced Knee usually lasts over 20 years.
1)Total Knee Replacement
Most total knee replacement operations involve replacing the joint surface at the end of your thigh bone (femur) and the joint surface at the top of your shin bone (tibia).
A total knee replacement may also involve replacing the under-surface of your kneecap (patella) with a smooth plastic dome. Some surgeons prefer to preserve the natural patella if possible, but sometimes the decision will need to be made during the operation.
If you’ve had a previous operation to remove the patella altogether (patellectomy), this won’t stop you having a knee replacement, but it may affect the type of replacement part (prosthesis) your surgeon uses.
The new parts are normally cemented in place. If cement is not used then the surface of the component facing the bone is textured or coated to encourage bone to grow onto it, forming a natural bond.
Another common technique is to use a mobile plastic bearing which isn’t firmly fixed to the metal parts. This may help to reduce wear on your new joint, though it isn’t hasn't been shown to provide better long-term results.
2)Unicompartimental Partial Knee Replacement
If arthritis affects only one side of your knee – usually the inner side – it may be possible to have a partial (unicompartmental) knee replacement
There are three compartments of the knee –
- The inner (medial)
- The outer (lateral)
- The kneecap (patellofemoral)
If arthritis affects only one side of your knee – usually the inner side – it may be possible to have a half-knee replacement (sometimes called unicompartmental or partial replacement). Because this involves less interference with the knee than a total knee replacement, it usually means a quicker recovery and better function.
Partial knee replacement isn’t suitable for everyone because you need to have strong, healthy ligaments within your knee. Sometimes this won’t be known until the time of surgery.
Research shows that people who have partial knee replacements are more likely to have the knee revised than people who have a total knee replacement – about 1 person in 10 needs further surgery after 10 years. Even though the operation involves less interference with the knee it is often a more complex operation than total knee replacement. Your surgeon may therefore prefer to offer you a more predictable total knee replacement.
Partial knee replacement can be considered at any age. For younger people, it offers the opportunity to preserve more bone, which is helpful if you need revision surgery at a later stage. For older people, partial knee replacement is a less stressful operation with less pain and less risk of bleeding. The outcome of the surgery, however, depends on the type of arthritis, rather than your age.
3) Kneecap Replacement (patellofemoral arthroplasty)
A kneecap replacement involves replacing just the under-surface of the kneecap and its groove (the trochlea) if these are the only parts affected by arthritis
It's possible to replace just the under-surface of the kneecap and its groove (the trochlea) if these are the only parts affected by arthritis. This is also called a patellofemoral replacement or patellofemoral joint arthroplasty
The operation has a higher rate of failure than total knee replacement – which may be caused by the arthritis progressing to other parts of your knee. Some surgeons advise a total knee replacement as the results are more predictable. Others feel that it’s better to preserve the rest of the knee joint if it isn’t affected by arthritis.
The operation is only suitable for about 1 in 40 people with osteoarthritis. However, the outcome of kneecap replacement can be good if the arthritis doesn’t progress and it’s a less major operation offering speedier recovery times. More research is needed to understand which people are likely to do well with this operation.
4) Complex or revision knee revision
A complex knee replacement may be needed if you're having a second or third joint replacement in the same knee, or if your arthritis is very severe.
Some people may need a more complex type of knee replacement. The usual reasons for this are:-
- Major bone loss due to arthritis or fracture
- Major deformity of the knee
- Weakness of the main knee ligaments.
These knee replacements usually have a longer stem, which allows the component to be more securely fixed into the bone cavity. The components may also interlock in the centre of the knee to form a hinge to give greater stability. Extra pieces of metal and/or plastic may be used to make up for any removed or badly damaged bone
This type of operation may be needed if you’re having a second or third joint replacement in the same knee, and could be better from the start if you have very severe arthritis.