March 30, 2020

Knee Replacement Surgery - Frequently Asked Questions

Written by Matija Krkovic

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As part of my NHS and private practice, I specialise in seeing patients who require knee replacement surgery. Most commonly patients require knee replacement surgery due to osteoarthritis, but they can also have rheumatoid arthritis, or arthritis following a traumatic injury to the knee. I am often asked questions in the clinic by patients who are anxious about their condition, and would like more information. I have put together some of the more common questions which patients have asked me, and will endeavour to shed some light on these so others who might be in a similar situation can benefit.

How long are typical NHS waiting times for knee replacement surgery?

The average waiting time knee replacement surgery in the NHS is 3-6 months, with variations from trust to trust. Following the COVID-19 pandemic, it is likely the waiting times are likely to be significantly longer due to disruptions.

How much does a knee replacement cost in the UK?

Knee replacement in the UK typically costs between £11,000 - £15,000 privately. The main reason the costs can vary is dependent on the level of co-morbidities a patient has, and which type of prosthesis is used.

How long do you have pain after a knee replacement surgery?

The majority of patients report that pain after a knee replacement surgery tends to resolve by around 3 months. Any pain still present after a year post knee replacement must be thoroughly investigated.

How long does a knee replacement surgery take?

A knee replacement surgery itself takes on average 1 hour to perform. In more complex cases this can extend to up to two hours, but rarely longer, not including revision knee replacement surgeries. Pre-operative preparation usually takes between 15-45 minutes. After the surgery, you will be in the recovery suite for 1-2 hours following which you will be transferred to the ward.

What are the best shoes to wear after a knee replacement surgery?

After a knee replacement surgery you should be wearing comfortable shock absorbing shoes with insoles. Good quality shoes can improve your gait, particularly in the early days post knee replacement surgery.

What are the criteria for knee replacement surgery?

The criteria for knee replacement surgery can vary from patient to patient. The main criteria are: disturbed sleep, limited distance of walking, pain on resting and/or activities, regular use of painkillers and walking aids.

How long after knee replacement surgery can I drive?

If comfortable you can drive 2 weeks after the surgery.

What are common problems after knee replacement surgery?

Common problems after knee replacement surgery are pain, muscle weakness and swelling. The main reason for increased pain is usually inadequate pain relief post knee replacement. This could be due to not taking enough painkillers when needed or because you were on significant painkillers for a longer period before the surgery.

Following knee replacement surgery, some muscle weakness is expected so it is extremely important that you keep your muscles as fit as possible prior to the surgery.

Sometimes patients can develop significant swelling after the knee replacement surgery. The main treatment is elevation of the limb post surgery with cryotherapy (i.e. a cold dressing) over the bandage, which usually reduces the swelling.

How long will I be in hospital after knee replacement surgery?

The average length of stay in the hospital after knee replacement surgery is 3-4 days. The sooner you can go home, the safer it is, providing that you fulfil all the criteria for safe discharge. By going home sooner rather than later you minimise the risk for contracting an infection in hospital and minimising the risk for blood clots to develop.

How much blood is lost after knee replacement surgery?

On average, up to half a litre of blood can be lost during knee replacement surgery. In the vast majority of patients, this level of blood loss will not affect them significantly, and the body will naturally replace the blood lost in the following weeks. For some people who become light headed or dizzy following the surgery, they may be experiencing low blood volume (known as hypovolaemia) and may require a blood transfusion.

Which exercises should I do before a knee replacement?

Before your knee replacement surgery it is extremely important that you keep your muscles fit. We will recommend you to do all exercises you are comfortable with and which do not causing you significant pain either during exercising or after. Exercises should be aimed towards keeping your muscles fit and maintaining the range of movement in your knee.

Which exercises should I do after a knee replacement?

After the knee replacement surgery you will be assessed by a trained physiotherapist who will then recommend you specific set of exercises to either do them on your own whilst in hospital or at home, or during your stay under physiotherapist supervision. The main emphasis during exercises will be on regaining muscle strength and improve mobility of your knee.

What should I expect in the first week after a knee replacement surgery?

After the discharge from hospital you will require some help at home with your daily activities. Whilst you should be able to mobilise around the house you won’t be able to do your own shopping, gardening, or any other labour intensive activities. You should be able to do all or majority of the day to day tasks including personal hygiene but you very likely won’t be able to do your cooking.

1-2 weeks after the discharge your abilities will improve daily and in about 4 weeks time post knee replacement surgery you should be able to do your shopping. You will need crutches indoors for 2-4 weeks post knee replacement surgery. For outdoor walking you will be advised to use crutches longer, on average up to 3 months.

How painful is a knee replacement?

Knee replacement surgery is a major operation, and so can be painful. However we take every step to minimise the pain you will experience. Before the operation you will be given general anaesthetic which will put you to sleep whilst we perform the surgery. During the operation, the anaesthetist will perform a targeted nerve block, where we inject anaesthetic to reduce the sensation in the nerves specifically around the knee for 12-48 hours. After the surgery is complete, we will inject more anaesthetic this time around the skin and wound itself to minimise any pain you may experience on waking up. Whilst you are in the recovery phase after the operation, we recommend that you need to be taking painkillers regularly after the operation. We find that patients who take painkillers regularly post knee replacement surgery have less pain and recover better compared to patients who start taking painkillers when already in pain.

Is a knee replacement a major operation?

The knee joint is the biggest joint in the human body. Knee replacement surgery is a major operation and it is treated as such. This is one of the main reasons that we have to make sure you are fit for the surgery before the knee replacement surgery takes place as you can sustain significant even life threatening complications if the assessment is not done and you are not adequately prepared.

What do they replace in a knee replacement?

In standard knee replacement surgery we would replace the end part of the thigh bone and top part of the shin bone. Areas which are/were covered by articular cartilage are removed and replaced by a metal prosthesis. The prosthesis can be made from different metals, cobalt-chrome or titanium being the most often used. Specially shaped plastic is then put in between both components to work as a shock absorber. This plastic can be of a different thickness, depending on the volume of bone which was resected. The level of resection of bone during the knee replacement surgery depends on the amount of bone affected by the primary disease (e.g. osteoarthritis, rheumatoid arthritis etc). If the knee cap doesn’t move well when the knee bends or if too damaged because of the disease, it will be replaced at the same sitting. When we replace the kneecap we actually smoothen the surface area and resurface it with a plastic button. You will need to ask your surgeon if the kneecap was resurfaced or not during the surgery as you cannot tell from the way your knee is functioning post surgery. Alternative you will be able to see it on the X-rays which will be taken next day post surgery.

For more information on knee replacement surgery written by Mr Matija Krkovic, click here

If you need a knee replacement surgery and would like a specialist review, please book a consultation today.

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