Knee replacements: is a robot or a surgeon better for the patient? For now, it’s a dead heat

Let’s face it. If you look at the precision involved in knee replacement surgery, the robot is probably more precise than the orthopaedic surgeon’s hand alone. But if you look at the long-term results, ultimately, the outcomes for patients are entirely comparable, whether the scalpel is wielded by the specialist or the machine performs the operation (always under human supervision, mind you). This reality is confirmed by a major study, the RACER-Knee study, which sets a benchmark in this field and was published in The Lancet (lead author Helen Parsons). The research was coordinated by experts from the University of Warwick and the University Hospitals Coventry and Warwickshire (UHCW) NHS Trust, and was prompted by the growing use of robotic techniques for knee replacement. According to a press release from the University of Warwick itself, in Australia just under one in two operations is carried out with robotic assistance. In the US, the figure exceeds 15 per cent, whilst in the UK it stands at around 6 per cent.

The aim of this approach, of course, is to facilitate the positioning of the prosthesis, based on the patient’s anatomical conditions. Total knee replacement is one of the most common elective surgical procedures for treating severe forms of knee osteoarthritis and, in terms of personalisation, alongside traditional orthopaedic surgery, the use of a robotic arm – controlled by the surgeon themselves – is becoming increasingly widespread.

This study is notable for being the world’s largest randomised, double-blind clinical trial, which compared conventional total knee replacement with surgery assisted by the most widely used robotic system. The results show that, one year after surgery, there were no significant differences between the two groups in terms of rehabilitation outcomes, joint mobility and, above all, pain. It is also worth noting that robotic-assisted knee replacement was not associated with an increased risk of serious adverse events, suggesting it has a similar safety profile to conventional surgery. The research was coordinated by Andrew Metcalfe, of the University of Warwick, an orthopaedic specialist surgeon at the UHCW NHS Trust, and Edward Davis, a consultant orthopaedic surgeon at the Royal Orthopaedic Hospital NHS Foundation Trust and honorary professor at the University of Birmingham. According to the latter, as reported in the University of Warwick’s press release, “the study shows that robotic assistance allows for greater precision and, in theory, the system should enable surgeons to tailor the procedure to the patient’s anatomy – that is Davis’s view –“. The expert’s view is therefore clear: it is necessary to tailor the approach to knee replacement on a case-by-case basis in order to personalise the surgical procedure and thus fully exploit the undoubted value of robotic systems in terms of precision.

The study examined 339 patients from 10 hospitals, treated by 33 surgeons across the United Kingdom, and found that no significant differences were observed in the assessment parameter (Forgotten Joint Score) one year after the operation. The score measures patients’ perception of the presence of the joint prosthesis during daily activities, and patients showed equivalent results, regardless of the method used for replacement. Patients also showed comparable results in terms of walking ability, pain perception during the first three months and at 12 months, pain during hospitalisation, and the likelihood of requiring further surgery. The aim now is to follow the participants in the study for ten years to assess any long-term differences between the two surgical methods and the need for further joint surgery. One final finding: robot-assisted total knee replacement procedures took on average around 10 minutes longer to perform but were not associated with an increased risk of serious adverse events.

In the future, if the use of robotic assistance could help surgeons adapt more effectively to each patient’s individual anatomy, the greater precision of the robotic system could prove to be a significant advantage. But only time will tell!