Robot-assisted knee replacement surgery improved the precision of implant positioning but produced no better patient outcomes than conventional surgery after one year, according to results from the RACER-Knee randomised clinical trial published in The Lancet. The UK study compared conventional total knee replacement with procedures performed using Stryker’s Mako robotic system. A total of 339 patients treated by 33 surgeons at 10 hospitals participated in the trial.
After 12 months, researchers found no meaningful difference between the two groups in the study’s primary outcome measure, the Forgotten Joint Score, which assesses how aware patients are of their artificial joint during everyday activities.
Patients also reported comparable results for mobility and pain. There were no meaningful differences in walking ability, pain during the first three months or at 12 months, pain experienced while in hospital, or the likelihood of requiring another operation during the initial follow-up period.
The robotic system did, however, allow surgeons to perform the procedure with greater precision. Robotic systems can assist surgeons in positioning instruments and adjusting cutting angles and depths according to an individual patient’s anatomy.
The greater surgical precision did not translate into improved clinical outcomes during the first year. Researchers also found no increased risk of serious adverse events among patients receiving robot-assisted surgery, indicating a similar safety profile to conventional knee replacement in the trial.
Robot-assisted procedures took an average of 10.5 minutes longer to perform and cost approximately £950 more than conventional operations. Based on current NHS cost thresholds, the robotic approach evaluated in the study was not considered cost-effective during the first year after surgery.
The National Institute for Health and Care Research funded the trial in partnership with Stryker. The study was coordinated by Warwick Clinical Trials Unit, University Hospitals Coventry and Warwickshire NHS Trust and the Royal Orthopaedic Hospital in Birmingham.
Researchers said the ability of robotic systems to reproduce surgical plans more precisely could become more clinically useful if techniques for tailoring knee replacements to individual anatomy improve. Further research will be required to determine whether different approaches to personalisation can convert that precision into improvements in pain, movement or implant performance.
Patients in the RACER-Knee trial will continue to be followed for 10 years. The longer-term study will examine whether differences emerge between robotic and conventional surgery, including whether either approach affects the likelihood of patients requiring further knee surgery.
Photo credit UHCW NHS Trust
