Knee Replacements don’t work as well as Hip Replacements – true or false?

Person's legs during workout

Some people with knee arthritis worry more about having a knee replacement than those with hip arthritis do about having a hip replacement. Why is this? Well the worry usually arises when people talk to others who have had a knee replacement or know someone who has had a knee replacement that hasn't gone so well. But that's not the whole story. As with most things in life, there can be some truth behind the concerns, but it is also true that modern knee replacements done by experienced specialist knee surgeons give reliable results in a vast majority of patients.

So what concerns do people have?

It doesn't always work

If patients have a knee replacement done for the right reasons, at the right time by the right (specialist) knee surgeon and have the right rehabilitation afterwards, then a predictably good result is the norm.  What is true is that whilst a well done hip replacement tends to work well in most people and requires relatively little rehabilitation,  knee replacements are more difficult to get right.

A specialist knee surgeon should take the time to talk to you in detail about your pain and its effect on your life, examine you and look at appropriate xrays. This will allow an accurate diagnosis of your condition and what treatment is required. Knee replacement may sometimes be delayed because pain is not yet bad enough and it is important that your surgeon replaces your knee when it needs replacing and not before. Otherwise there will be a danger that, at best,  the relief of pain won't be as expected, and at worst, should you suffer a complication, you will regret having the procedure done.  Where replacement surgery isn't required because things aren't bad enough yet, other treatments should be offered to help with ant pain that exists.

When the time comes to have a knee replacement, patients can rest assured that it is a reliable and successful operation provided it is performed by a surgeon who is specially trained and skilled in knee replacement surgery. Knee replacement is technically more difficult to get right than hip replacement and this is one important reason why some patients have poorer results than others. A surgeon who does a good number of knee replacements will tend to have better results, but this is not the whole story. Planning the surgery carefully in advance, meticulous attention to detail during the procedure, using specific techniques to make the replaced joint perform perfectly and supervising rehabilitation afterwards are all absolutely essential. The surgeon should also be meticulous about measures to prevent complications including infection. The result will then be predictably good in a vast majority of patients.

It is a very painful procedure

Modern knee replacement involves paying careful attention to keeping patients comfortable at all stages. Some pain will undoubtedly be experienced but this should always be manageable. It is controlled by appropriate medication and by regular icing.

Patients have little pain relatively speaking,  after a hip replacement, but after a knee replacement things differ because the knee is a very different joint. The knee can swell and feel tight and stiff. The arthritic pain disappears straightaway but is replaced by a tight stiff pain for a period of time. Patients also have to work to gain a good knee bend. There is no doubt that things differ from patient to patient, but another important factor is how well the surgery is performed including how carefully the tissues are handled, how the replacement is positioned and even how carefully the wound is closed. Some surgical techniques can help the knee feel more natural after the surgery and allow patients to progress very quickly with minimal pain.

All patients can expect to be walking on the day of surgery or certainly the morning after. Most of Mr Sood's patients go home on the second day after surgery and are mobile, have a knee that bends well and have good pain control.

A lot of physiotherapy is needed afterwards

Physiotherapy is certainly needed afterwards, usually 6-8 sessions, but well performed surgery makes the physiotherapists job much easier as movement is regained quickly and strengthening of muscles occurs more quickly.

It is important that your surgeon also partners with you in your rehabilitation and recovery. This should involve reviewing your progress and identifying what is amiss if things are going more slowly than usual to help you get back on track. Liaison with your physiotherapist as necessary is also important.

When movement is not regained as quickly as necessary it is sometimes necessary to manipulate the knee under a brief anaesthetic. This should not be needed very often. As a guide, Mr Sood manipulates on average one of his knee replacements a year (less than 1%).  High rates of manipulation are more common with knee replacements that are performed by non-specialised Orthopaedic surgeons.

The knee won't bend like before

In general, a well performed knee replacement should bend as much as the knee did before the replacememt. In cases where the knee bend is poor before surgery, special techniques during surgery should allow the amount of bend to be improved, sometimes very significantly, but again your surgeon needs to be skilled in dealing with such problems.

I won't be able to kneel

This is an interesting one. In fact there is no reason why patients can't kneel after a knee replacement. This is the case whether or not the knee cap is resurfaced. Kneeling does not damage the replacement in any way. Some people are able to kneel without any issues whereas others don't. Studies show that 60-80 % of people can in fact kneel after total knee replacement when encouraged to do so and reassured but that only 40-50% of people kneel without such encouragment.  There are a number of  possible reasons for patients not kneeling. Some patients are given conflicting or unclear advice about kneeling by others and so are fearful of kneeling. Others avoid it because it doesn't feel right. This may be because the knee doesn't bend enough to allow proper kneeling or can relate to the sensation over the skin on the front of the knee being slightly altered, a common and unavoidable consequence of having a surgical cut over the front of the knee.

Once more the influence of having surgery performed well so that a good bend is achieved is underlined.

Mr Sood encourages patients who want or need to kneel, to try to kneel regularly and often gets his patients to try this in clinic when they attend for follow-up so that they feel safe and reassured.


You can be reassured that a predictably good result after knee replacement surgery can be expected if the circumstances are right. Assessment should be detailed and knee replacement surgery offered appropriately and at the right time by a specialist knee surgeon who understands how to do the operation well. Such a surgeon will be able to achieve good results even in more complex cases by planning the procedure and employing specialist techniques where necessary. Choose your surgeon carefully. If the same surgeons name comes up repeatedly from people who have had good results, this can be an important way to help make the choice. It is also important to see a surgeon who can offer the whole range of treatment options and doesn't recommend knee replacement surgery before it is necessary.  Good luck.