Robot-assisted knee replacement surgery is more precise than surgeon-only surgery, but it does not currently improve patient outcomes.
This is according to the RACER-Knee trial, the world's largest clinical study of its kind.
The trial makes an important contribution to the evidence on robotics in health care and where future advances and research should focus. Coordinated by the University of Warwick and University Hospitals Coventry and Warwickshire (UHCW) NHS Trust, it is published in The Lancet.
Robotic assistance is increasingly used in knee replacement surgery worldwide – six per cent of procedures in the UK, 16% in the US and 42% in Australia.
The aim is to help surgeons place the knee replacement more precisely and tailor surgery to a patient’s anatomy.
The National Institute for Health and Care Research (NIHR) funded the UK-wide RACER-Knee trial in partnership with Stryker, which makes the robot that was tested. It was led by the Warwick Clinical Trials Unit, UHCW NHS Trust and the Royal Orthopaedic Hospital in Birmingham. It is the world's largest double-blinded randomised control trial comparing conventional total knee replacement to surgery assisted with the Stryker Mako robotic system, the most widely used system globally.
The trial found that one year after surgery, patients in both groups had similar recovery, mobility and pain levels. While robotic assistance was more precise, it did not translate into improvements in patient outcomes within the first year after knee replacement. The trial also found that robot-assisted knee replacement was not linked to an increased risk of serious adverse events, suggesting it was as safe as the usual approach.
The study was led by two chief investigators in the UK.
Professor Andrew Metcalfe, Warwick Medical School, University of Warwick, and Consultant Orthopaedic Surgeon at UHCW NHS Trust: ‘We are delighted to have completed this world-leading randomised trial of an exciting technology that is now being used globally and at scale. It is an important step in the process of innovation and will stimulate lots more high-quality studies. Technology such as this could really help the care we give for patients, but for robotic-assisted knee replacements, there is still work to do before we see benefits such as less pain or better movement.’
Professor Edward Davis, consultant orthopaedic surgeon at The Royal Orthopaedic Hospital NHS Foundation Trust, added: ‘The trial demonstrates robotic-arm assistance allows for higher precision, and in theory the system should allow surgeons to customise the procedure according to a patient’s anatomy. These results are by no means a condemnation of the robotic systems, but more understanding of the ideal position for a knee replacement and personalisation for each patient is needed. We’ll then be able to truly take advantage of the advanced precision of robotic systems.’
Professor Anthony Gordon, Director for the NIHR Health Technology Assessment (HTA) Programme, said: ‘Innovation in healthcare depends on evaluating promising technologies rigorously and at scale. While this study shows robotic-assisted knee replacement is not yet improving patient outcomes, it highlights opportunities to refine these technologies and harness their precision to deliver better care in the future.’
The researchers will continue to follow up patients for 10 years to see whether there are any long-term differences between the two approaches. Importantly, this might find out if there is a difference in the number of patients needing more surgery for their knee.
