Robotic surgery does not always reduce the risk of reoperation

Robot-assisted surgery is often associated with greater surgical precision, faster recovery and fewer complications. However, new British research shows that these benefits do not automatically apply to every procedure. In the case of hip and knee replacements, robot-assisted surgery did not result in a lower overall risk of reoperation in the first few years following surgery compared with conventional surgery.

This is evident from two large-scale studies by Queen Mary University of London, the University of Oxford and the University of Bristol, published in The BMJ. The researchers analysed data from more than one million hip and knee replacements registered in the UK National Joint Registry between 2018 and 2024. According to the researchers, this represents the largest real-world analysis to date of the outcomes of robot-assisted joint replacement.

Greater precision, but no reduction in reoperations

In robot-assisted hip and knee surgery, the surgeon retains control of the operation. Computer and robot technology assist with planning the procedure and precisely positioning the implant. It is expected that improved positioning may contribute to a longer lifespan of the prosthesis and fewer reoperations.

However, the new studies find no overall benefit in this regard in the short term. For both knee and hip prostheses, the overall risk of a repeat operation was no lower in patients who had undergone robot-assisted surgery.

A specific benefit was, however, found in hip surgery: patients in the robot-assisted group were less likely to require a reoperation due to incorrect positioning of the implant. That difference was, however, insufficient to reduce the overall number of reoperations. The researchers also found no overall difference in mortality rates. Similarly, no difference in the risk of reoperation was observed for knee replacements. The researchers emphasise that these are early results. Longer-term follow-up should clarify whether, for example, the greater precision leads to a longer lifespan for implants in the long run.

A different picture from previous studies

The findings are striking because previous studies into other types of robotic surgery actually demonstrated clear benefits for patients. This was shown, for example, in an earlier randomised British study involving 338 patients with non-metastatic bladder cancer, in which robotic-assisted surgery was compared with open surgery. Within ninety days, 21 per cent of the robot-assisted group were readmitted, compared with 32 per cent of patients who had undergone open surgery. Patients also spent an average of two days less in hospital following robot-assisted surgery.

Benefits have also been reported in the case of colorectal cancer. In a study involving 578 patients, those who underwent robot-assisted surgery reported less pain and used fewer opioids than patients who underwent laparoscopic surgery.

The studies cannot be directly compared with one another. They involve different types of surgery, control groups and outcome measures. It is precisely for this reason that the new findings emphasise that conclusions regarding the added value of ‘robotic surgery’ cannot simply be applied from one procedure to another.

Costs versus clinical added value

This debate is becoming more relevant now that the UK’s NHS intends to significantly expand the use of robotic surgery. According to the researchers, the introduction of a robotic system costs around one million British pounds, and robotic assistance can add an extra 1,000 to 2,500 pounds per procedure.

For their analysis, the researchers used a method known as ‘target trial emulation’. This involves analysing observational registry data statistically in such a way that patient groups become more comparable based on known characteristics. However, this remains a study based on real-world data and is not a randomised clinical trial.

According to lead researcher Hasan Mohammad, the study comes at a crucial time, as robot-assisted hip and knee surgery is being rapidly adopted. In his view, new technology must not only be technically more advanced, but also deliver demonstrable benefits for patients and justify the investment within a publicly funded healthcare system.

The results do not, therefore, imply that robotic surgery as a whole offers no added value. Above all, they show that greater technical precision is, in itself, insufficient evidence of better clinical outcomes. The benefits of robotic assistance will need to be determined on a procedure-by-procedure basis and in relation to relevant patient outcomes.