New Delhi, Oct. 3 -- Robot-assisted hip and knee replacements produce no better results than conventional surgery, two large UK studies have found, raising questions over how quickly hospitals, including in India, have adopted the technology. The studies, published in The BMJ, drew on National Joint Registry data for 666,283 total hip replacements, 10,203 of them robotic, and 697,145 total or partial knee replacements, 22,111 of them robotic, performed in UK public and private hospitals between 2018 and 2024. The researchers matched patients for factors including age, sex, body mass index, diagnosis, physical fitness, implant type and surgeon volume. They then found no difference in implant survival, revision risk or complications during surgery over an average of 2.5 years. Patient survival after hip replacement did not differ either. Earlier studies showed that robotic systems, which use computer-controlled arms and high-definition cameras, improve implant placement. They did not show whether this leads to better outcomes. The NHS plans to expand robotic surgery sevenfold by 2035. The authors wrote that the results question that plan, given upfront costs of around £1 million and an extra £1,000-2,500 per patient. The National Institute for Health and Care Excellence has called for urgent research into the effect of robotic surgery on revision risk. Robotic joint replacement has also spread rapidly in India over the past decade, mainly in the private sector. "The results aren't astonishing. This has been common knowledge within the medical fraternity that there's not as big advantage over conventional surgery as it was made out to be. It was a means to basically promote your implant as it would largely require an implant from the same company that manufactured the robot. Sooner or later such results are going to surface, and that's why corporate interests should always be kept in mind. Long-term results show that advantages have been hyped," said Dr Shah Alam Khan, professor of orthopaedics at the All India Institute of Medical Sciences (AIIMS), New Delhi. The authors cautioned that the studies are observational and cannot establish cause and effect. They added that unmeasured factors may have influenced the results and that the short follow-up could mask longer-term outcomes....