Almost 100,000 total and partial knee operations are carried out every year in the UK and increasingly robots are helping to increase the accuracy of the surgery.

"Robotics has improved accuracy of operations and speed up recovery time."

Knee replacements are a cost-effective treatment for the NHS because more than 95% of implants are still in place 10 years after surgery1. Operations are usually undertaken to treat later-stage osteoarthritis.

Dinesh Nathwani, head of orthopaedic surgery at Charing Cross and St Mary’s Hospitals in London, says more people, including those in middle age, could benefit from new knees if computer navigated surgery technology was more widely adopted.


Computer-navigated surgery


He has been using technology in partial and total knee replacements for 17 years and says the recent advent of robotics improves the accuracy of operations and speeds up recovery time.

The robot is a hand-held mechatronic device which is totally controlled by the surgeon to help them position implants to suit a patient’s anatomy.

"More accurate cuts mean less bone and tissue, such as ligaments and cartilage, needs to be removed."

Aided by a computer, the surgeon can site the knee replacement more precisely. This can improve longevity and potentially reduce the risk the implant will become loose, wear out quicker or not function properly.

Mr Nathwani says navigation surgery also makes the cuts more accurate because less bone and tissue, such as ligaments and cartilage, needs to be removed.

“All cuts can be checked accurately in real time during surgery so that any mistakes or errors can be rectified,” he says. “With conventional surgery, errors are often only seen once the patient is mobile and has had an X-ray after the operation.”

The technology can also be used for hip replacement  and potentially shoulder and ankle replacements in the future.


Surgeon in control


Charing Cross is one of the first hospitals in the country to install a Navio robotic system to perform robot assisted knee surgery.

This impressive piece of kit reduces radiation exposure because patients do not require a CT (computed tomography) scan. The software collects joint laxity data and uses soft-tissue and 3D surface capture to ensure the surgeon positions the implant in the right place.

The machine is also collecting data on patients during their operation and the insight being generated will be used to improve the technology.



One of the reasons navigated surgery has not been widely adopted is because operations can take around 20 minutes longer. Additional time is needed to set up the technology and to ensure the actual knee matches the implant plan. There is no increase in the rate of infection or other complications, however.

"The only downside is that operations take about 20 minutes longer."

Mr Nathwani insists that as well as accuracy, one of the biggest benefits is a quicker recovery rate. “At Charing Cross I have sent two patients home as day cases which would have been extremely unlikely a few years ago” he says.

Navigated and robotic surgery could reduce the complications experienced when only part of a knee is replaced. These operations can be technically-difficult, but by using robots potentially more procedures could be performed safely on an outpatient basis away from hospitals. 


Active in middle age


The technology may also benefit people in middle age who tend to have a higher failure rate following an operation because they want to remain active, and this puts more demands on their new knee.

“People are wearing out their joints earlier and they want solutions at a younger age.”

Mr Nathwani says “people are keen to get back to playing golf or running, and with navigated and robotic surgery we can help people in their early 50s who have some pain rather than telling them they must wait until there are older for a total knee replacement.”


1 National Joint Registry for England and Wales and Northern Ireland