Robotic hip arthroplasty was associated with about 2 mm less leg-length discrepancy

Design

Systematic review and meta-analysis of 7 comparative studies

Population

968 patients undergoing robotic or conventional THA

Primary outcome

Leg-length discrepancy, cup orientation, early hip scores

Effect

LLD MD -2.02 mm (-3.46 to -0.58); Harris Hip Score MD 2.96 (1.12 to 4.80)

This meta-analysis pooled seven comparative studies (968 patients), mostly nonrandomised, of robot-assisted versus conventional total hip arthroplasty.

Robotic surgery was associated with a smaller leg-length discrepancy (mean difference -2.02 mm, 95% CI -3.46 to -0.58), slightly lower cup anteversion, and no difference in inclination. Early scores were higher: Harris Hip Score by 2.96 points, Oxford Hip Score by 2.61 and Forgotten Joint Score by 14.68.

A 2 mm difference in leg length is unlikely to be felt by most patients, and the Harris and Oxford differences fall below commonly quoted thresholds for a noticeable change. The Forgotten Joint Score difference is larger but heterogeneous. With few studies and mostly nonrandomised designs, the case for robotic THA on outcomes alone remains unproven.

• Robotic THA gave modestly better leg-length restoration, about 2 mm
• Early functional score gains were small and mostly below noticeable thresholds
• Evidence is mainly nonrandomised; weigh cost and theatre time accordingly
• Careful templating and intraoperative checks remain the standard for leg length without a robot

Why it matters

It gives numbers to weigh against the cost of robotic systems now spreading in Indian private hospitals.

Don't overread it

Seven mainly nonrandomised studies with marked heterogeneity cannot show that robotics improves function.

The statistics, in plain English

A mean difference of about 3 points on the Harris Hip Score is statistically significant but smaller than the change most patients notice. Heterogeneity means the studies gave inconsistent results.

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