iASSIST knee replacement

Bluetooth technology helps surgeons pinpoint the position of the joint.

The iASSIST total knee replacement is an advanced surgical guidance system designed to improve the accuracy and alignment of total knee replacement surgery.

Why you might need it

Knee replacement surgery replaces the damaged or worn parts of the thigh and shin bones which form the knee joint. During the operation, the damaged or worn parts are replaced with metal and plastic parts that glide over each other smoothly. The average recovery time is about six months.

If you decide to have a knee replacement with us, you’ll be looked after by an experienced multidisciplinary care team who understand what you’re feeling and are dedicated to your well being.

The iASSIST total knee replacement is an advanced surgical guidance system designed to improve the accuracy and alignment of total knee replacement surgery. This helps to assist the surgeon in precisely aligning knee implants to each patient’s unique anatomy, providing a personalised fit.

Traditional knee replacements may use instruments placed inside the thigh or shin bone to assist with alignment and positioning. The iASSIST knee system allows surgeons to create a straight joint without using these invasive methods.

Find a Spire hospital offering this treatment

Who will do it?

Our patients are at the heart of what we do and we want you to be in control of your care. To us, that means you can choose the consultant you want to see, and when you want. They'll be with you every step of the way.

All of our consultants are of the highest calibre and benefit from working in our modern, well-equipped hospitals.

Our consultants have high standards to meet, often holding specialist NHS posts and delivering expertise in complex sub-specialty surgeries. Many of our consultants have international reputations for their research in their specialised field.

Before your treatment

You will have a formal consultation with a healthcare professional. During this time you will be able to explain your medical history, symptoms and raise any concerns that you might have.

We will also discuss with you whether any further diagnostic tests, such as scans or blood tests, are needed. Any additional costs will be discussed before further tests are carried out.

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Preparing for your treatment

We've tried to make your experience with us as easy and relaxed as possible.

For more information on visiting hours, our food, what to pack if you're staying with us, parking and all those other important practicalities, please visit our patient information pages.

Our dedicated team will also give you tailored advice to follow in the run up to your visit.

The procedure

The surgeon attaches a 2-3cm pod to a tiny 1cm spike at the bottom of the thigh bone. The pod contains a sensor that responds to movement, like the sensors in a smartphone which turn the text the right way up when you turn the phone on its side.

The pod transmits information via bluetooth wire-free technology which communicates to a computer - to help the surgeon pinpoint exactly where to position the new joint.

The surgeon then moves the patient’s knee through 12 positions and the computer calculates when the joint is in the correct place.

iASSIST knee system requires no complex imaging equipment or additional surgical incisions, it aims to deliver the best possible fit for patients undergoing total knee replacement.


After this, you will be taken to your room or comfortable area where you can rest and recuperate until we feel you’re ready to go home.

While you are in hospital a physiotherapist will help you every day with exercises that will help speed up your recovery.

Pain relief

You will most likely feel some pain and swelling in your knees immediately following your surgery. We will give you medication while you’re with us and to take home to help ease any pain, and we will provide you with a supply of all the medicines your consultant feels you need to take home with you after you've left hospital, up to 14 days. This may be at an additional cost to some patients.

Recovery time

For the first day or so, you may have a compression pump attached to special pads on your lower legs. By inflating the pads, the pump encourages healthy blood flow and helps to prevent DVT (deep vein thrombosis or blood clots). Afterwards, you may also have compression stockings on your legs.

Some people are able to walk on the same day of their operation but you will initially experience discomfort when walking and exercising. But we are all different and our recovery times and the speed with which we can return to everyday activities varies.

After about six months, your knees should be healed.

How your loved ones can help

Once you’re ready to be discharged from hospital, you’ll need to arrange a taxi, friend or family member to take you home as you won’t be able to drive for a few weeks.

You may be asked to wear compression stockings for several weeks at home. These are difficult to put on and take off, and you'll need someone to help. You'll be able to move around your home and manage stairs, but may find that some routine daily activities, such as shopping, are difficult for a few weeks and you’ll need some help with light errands.

Looking after you

Even after you’ve left hospital, we’re still looking after you every step of the way. After a knee replacement, we will provide you with all the appropriate medication, physiotherapy exercises, advice on what to do and not to do with your knee and follow-up medical support.

Typically your consultant will want to see you after your treatment to see how you’re doing and an appointment will be made for you before you leave the hospital. You might also be seen by a physiotherapist.

On rare occasions, complications following a knee replacement can occur. The chance of complications depends on the exact procedure you are having and other factors such as your general health. You should ask your surgeon to explain how these risks apply to you.

We will talk to you about the possible risks and complications of having this procedure and how they apply to you.

If you have any questions or concerns, we’re ready to help.

Why choose Spire?

We are committed to delivering excellent individual care and customer service across our network of hospitals, clinics and specialist care centres around the UK. Our dedicated and highly trained team aim to achieve consistently excellent results. For us it's more than just treating patients, it's about looking after people.

Important to note

The treatment described on this page may be adapted to meet your individual needs, so it's important to follow your healthcare professional's advice and raise any questions that you may have with them.

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