World's Largest Trial of Robotic Knee Surgery Delivers Surprising Results

The RACER-Knee clinical trial published on August 20, 2026, in The Lancet evaluated the world's largest double-blinded randomized controlled trial comparing conventional total knee replacement with robot-assisted surgery using the Stryker Mako system. The study involved 339 patients treated by 33 surgeons across 10 hospitals in the UK to determine whether increased surgical precision translates to better patient recovery. The study concluded that while robot-assisted knee surgery delivers significantly greater precision in positioning implants, it does not improve patient recovery, pain reduction, mobility, or function during the first year after surgery. Both robotic and conventional groups showed similar outcomes measured by the Forgotten Joint Score, walking ability, and pain levels, proving that current technological accuracy does not yet yield perceptible clinical benefits for patients. Economically and operationally, robotic-assisted total knee replacements required an average of 10.5 minutes longer to perform and cost about 950 British pounds more per procedure. Under current National Health Service cost limits, the system was not cost-effective during the first postoperative year, although the procedures demonstrated safety profiles comparable to conventional methods with no increase in serious adverse events. Researchers plan to monitor trial participants for ten years to evaluate long-term outcomes such as implant durability and revision rates. The findings serve as a critical benchmark for healthcare innovation, indicating that surgeons and developers must gain a deeper understanding of personalized anatomy and ideal implant positioning to successfully translate mechanical precision into meaningful patient-felt benefits.