Robotic TKA matches conventional TKA on function and pain, and takes longer

Design

Meta-analysis of randomised controlled trials with meta-regression

Population

3,425 patients in 24 RCTs of robotic vs conventional TKA

Primary outcome

Change in WOMAC function, KSS function and Oxford Knee Score

Effect

WOMAC MD 0.14 (−5.88 to 6.16); operative time +22.34 min (13.66 to 31.02)

This meta-analysis pooled only randomised trials: 24 RCTs with 3,425 patients comparing robotic-assisted with conventional total knee arthroplasty, with meta-regression and platform subgroups.

There was no difference in change in WOMAC function (mean difference 0.14, 95% CI −5.88 to 6.16), functional Knee Society Score (0.51, −3.43 to 4.44) or Oxford Knee Score (2.07, −6.82 to 10.96). A 6-month Oxford score gain in one subgroup (2.25 points) fell short of the minimal clinically important difference and was not sustained. Pain, range of motion, satisfaction and stay did not differ. Robotic cases took about 22 minutes longer (13.66 to 31.02), with very high heterogeneity (I² 98.5%) likely reflecting learning curves. Certainty was low to very low throughout.

This matters for purchasing decisions and for how robotic surgery is described to patients, including in Indian private hospitals where robotic knee replacement is increasingly marketed. The trials support robotics as an alternative, not a superior option. Long-term survivorship, where alignment precision might matter, is not yet answered.

• Tell patients that robotic and conventional TKA give similar function and pain relief at the follow-up studied.
• Do not present robotic TKA as producing better outcomes in consent discussions or marketing.
• Plan for longer theatre time, especially early in a surgeon's robotic learning curve.
• Base purchasing decisions on workflow and training value, not on patient-reported benefit, which these trials did not show.

Why it matters

It undercuts the patient-facing claim that robotic knees recover better.

Don't overread it

Evidence certainty is low to very low, and long-term implant survival is not addressed.

The statistics, in plain English

A mean difference of 0.14 on WOMAC with an interval from about −6 to +6 means any true difference is likely small in either direction. The operative time estimate varies enormously between trials (I² 98.5%), so the 22-minute figure is an average of very different experiences.

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