Knee Replacement Surgery FAQ Page 1

What is arthritis?

Osteoarthritis (OA) is wear to or failure of a joint lining down to bare bone-on-bone. Many people use the term osteoarthritis to dismiss vague aches and pains that they resign themselves to put up with, but osteoarthritis is something specific and usually treatable. Osteoarthritis can cause pain, stiffness, bony lumps, bow or knock kneed legs and swelling.

Hip and knee replacements are examples of major operations for osteoarthritis, but for other areas in the body smaller operations may be appropriate too. Surgery for osteoarthritis is generally the last resort and there are many non-operative treatments which can also be discussed with the doctor.

Other types of arthritis, like rheumatoid or psoriatic arthritis, are often treated by a rheumatologist. An orthopaedic surgical opinion may be useful in these cases too if a lot of damage has been done to the joints.

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What is osteoporosis?

Osteoporosis is a condition often associated with ageing, in which bones become weaker and break more easily. It is something to ask your general practitioner about as it is known to be associated with other medical conditions or medications.

If you are middle-aged or older and have broken a bone it is also something to have checked out. There are tests to rule out important causes and there are effective treatments. If someone has osteoporosis it doesn’t mean they can’t have a knee replacement.

Osteoporosis is sometimes confused with osteoarthritis as both can be shortened to osteo.

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Can my worn-out knee get too bad for an operation?

Normally it isn’t possible to let your worn-out knee get too bad for surgery. Actually it is usually in the best interests of your health to put joint replacement surgery off for as long as possible.

Your own worn-out knee is normally tough and won’t disintegrate or grind away to nothing. People also worry about the worn knee joint throwing other joints out and causing damage to something else, but that wouldn’t typically be a reason to proceed with surgery. If a joint near or opposite the first one subsequently wears out then realistically it was probably going to do so anyway.

In general, the decision to proceed with knee replacement surgery is made when the problem with the knee or knees is bad enough that it makes sense to proceed with surgery in its own right. The surgery is to alleviate current trouble rather than protect against problems in the future.

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Am I too old for a knee replacement? If I put it off will I be too old?

No one is really too old for a joint replacement. It is important to make a careful and considered decision about proceeding with major surgery in all age groups, but this is especially the case in the very elderly.

A joint replacement is never out of the question, as long as your medical fitness allows it. Dr Martin takes time with elderly patients to really get to the bottom of their issues and to help the patient decide whether an operation is right for them or not.

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Am I too young?

Joint replacements don’t last forever and younger people wear them out more quickly. However, the results of surgery in young people are improving and so there probably isn’t a need for a hard and fast cut off like there used to be.

Despite this there are still good reasons to avoid a knee replacement in a younger person if at all possible. As a rough guide Dr Martin would try to avoid doing knee replacements under the age of 50.

If you are young and having a lot of trouble from bad knee arthritis then it isn’t a straightforward situation. That is a good reason to see an orthopaedic surgeon to talk through the different options and associated decision-making.

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How do I know if my knee is bad enough for a knee replacement?

Firstly an x-ray or scan is necessary to confirm bone-on-bone arthritis in your worn-out knee. A knee replacement is not an option to consider without bone-on-bone wear.

After that it is important to realise that not everyone with a worn-out knee needs a knee replacement. How you know if it is for you basically comes down to whether you are having a bad time with miserable knee pain after having tried the sensible alternatives.

It is major surgery and not something you should undertake for a niggle or so that you can do something very demanding that isn’t reasonable for your age group. It is, however, a very good operation for someone who is having significant trouble with day to day things due to knee arthritis.

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How long will the replacement last?

This is a very common question and it’s very important to understand the answer, but it isn’t straightforward. The results of knee replacements are very good and you can expect your joint replacement to last a long time, but this does depend a bit on your age, activity level and the underlying condition that required joint replacement surgery.

For most people the knee replacement would last more than 15 years and chances would be good that it might last as long as 20 or 25 years or more. There is, however, a small risk of failure at any time after knee replacement surgery for various reasons. There is even about a 1 in 100 chance of failure within the first year.

Examples of steps that Dr Martin takes to improve the chances of your joint replacement lasting a long time include the choice of a prosthesis based on The Australian National Joint Replacement Registry results, the use of computer navigation and careful technique during the surgery.

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How long does the operation take?

A knee replacement usually takes around 90 minutes. Having both sides done at once takes 3 to 4 hours. A patient will often be gone from the ward for 4 hours or more surrounding their operation, so do not worry if a family member is having joint replacement surgery and it seems to be taking a long time.

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What sort of anaesthetic can I have?,

Most times the operation can be done under either general or spinal anaesthetic, but there can be situations where the anaesthetist would choose a specific anaesthetic for safety. In routine cases where either is possible, Dr Martin strongly recommends a spinal anaesthetic as that is overall a bit safer, with a better recovery and importantly better post-operative pain relief.

The trend towards more spinals rather than general anaesthetics has been one of the key things that has helped people recover more rapidly and comfortably from knee replacement surgery in recent years.

Some people are anxious about being able to hear the surgery with a spinal. Be reassured that this isn’t a problem, because the anaesthetist can easily make you doze with a spinal on board. If, for medical reasons it isn’t possible to do the operation under a spinal then a general is still fine, but if you have the choice, go for a spinal.

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How much pain will there be after the surgery?

The pain associated with major knee surgery isn’t nearly as bad as it used to be. This is due to a combination of improvements in technique and pain relief.

Occasionally someone will have significant post operative pain, but there are always further steps available to get the pain under control to the point where it is manageable. Dr Martin is focused on minimising your pain after the surgery and is constantly striving to improve the experience for patients recovering from knee replacement surgery.

Dr Martin strongly believes you shouldn’t need to have an unusually high pain tolerance to recover well from a knee replacement.

Examples of the steps that can be taken to minimise the pain from a knee replacement are the use of a less painful incision such as the subvastus approach, multimodal pain relief, minimised tourniquet time, attention to bandaging and bleeding control, amongst other things.


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How long would I stay in hospital?

Patients are discharged when they are safe and comfortable to go home. With current techniques this is often as early as 1-2 days after the surgery. For appropriate patients who would find a very short stay in hospital convenient, Dr Martin can offer a 24 hour stay for the surgery.

If you are planning to go home early after the surgery it is important to have someone at home with you at first.

Dr Martin is continually working towards greater comfort and enhanced recovery for patients after knee replacement surgery. He uses a multi-faceted approach that helps patients get home from hospital quickly, safely and comfortably, where appropriate. This includes the use of a less painful incision, such as the subvastus approach, multimodal pain relief, minimised tourniquet time, attention to bandaging and bleeding control, amongst other things.

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How long will it take until I am better?

The recovery from major joint replacement surgery is much faster than it used to be, but it is different for everyone and even different from knee to knee for people who have had both done. Some people reach the point where they are back doing what was normal for them with their bad knee before the surgery as early as 2 weeks after the surgery.

For most people it takes 4 to 6 weeks until they are better than before the operation and reach the point where they are glad they have had the operation done.

It is important not to be disappointed if your knee is getting better more slowly than average! Occasionally people can experience a slower recovery. About 1 in 50 patients might take as long as 6 months until they are pleased with the new knee. From then on the knee would continue to get slowly better until the new knee is fully “bedded in”, which can take as long as a year.

Examples of technical steps that can help facilitate an earlier recovery include the use of a less painful incision such as the subvastus approach, multimodal pain relief, minimised tourniquet time, attention to bandaging and bleeding control amongst other things.

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How long until I can drive?

It isn’t recommended to drive until 6 weeks after knee replacement surgery. This is to ensure safety when reacting to an emergency. Patients who can walk well without any assistance and aren’t affected by strong pain killers may be safe to drive before 6 weeks, after discussion with the doctor.

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How active can I be after the operation?

Dr Martin recommends you avoid impact sports after knee replacement, including running or jogging. Long walks, bike riding, swimming, golf or doubles tennis would be examples of reasonable levels of activity. If you are keen to undertake impact sports after the surgery it is important to talk that over with Dr Martin.

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Can it be done again?

In most cases it is possible to re-do a failed knee replacement. In most cases it is even possible to re-do it more than once. This is called a revision. Usually it is a bigger operation with higher risks and worse results than a successful first (called primary) knee replacement. Very occasionally it may not be possible to re-do the failed joint, but that really is unusual.

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