Evaluating Spin Bias in the Abstracts of Systematic Reviews and Meta-Analyses on Robotic-Assisted Total Hip Arthroplasty: A Systematic Review.

Abstract

Background: Interest in robotic-assisted total hip arthroplasty (RA-THA) continues to grow, despite inconsistent evidence on its effectiveness.

Purpose: We sought to assess for the presence of spin bias in abstracts of systematic reviews and meta-analyses (SRMAs) comparing RA-THA to conventional total hip arthroplasty (C-THA).

Methods: We conducted a systematic review of studies identified in a comprehensive search of MEDLINE, EMBASE, and the Cochrane Database of Systematic Reviews from each database's inception to June 23, 2025. Search terms included "robotic," "hip," "arthroplasty," "systematic review," and "meta-analysis." Inclusion criteria were (1) SRMAs evaluating outcomes of RA-THA, (2) studies comparing RA-THA to conventional techniques, and (3) publications in English. Studies were excluded if they (1) assessed RA-THA with other robotic-assisted joint arthroplasty procedure, or (2) assessed RA-THA surgery alongside other technologies. Abstracts were assessed for the 15 most severe forms of spin as defined by Yavchitz et al. Methodological quality was assessed using the AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews-2) tool.

Results: Twelve SRMAs were eligible for inclusion. Eleven SRMAs (91.7%) contained at least 1 of the 15 most severe forms of spin. Type 3 spin (selective reporting of efficacy outcomes favoring the intervention) was the most common (58%), followed by type 5 (conclusion claims the beneficial effect of the experimental intervention despite high risk of bias in primary studies; 50%), and type 11 (conclusion focuses selectively on statistically significant efficacy outcome; 33.3%). No differences in study characteristics were found between SRMAs with and without the aforementioned types of spin. All SRMAs were rated as "critically low" in methodological quality, with most not reporting funding source of included studies (91.7%).

Conclusion: This systematic review found there is a high prevalence of spin bias in abstracts of SRMAs evaluating RA-THA. The most common type of spin involved selective reporting of outcomes favoring RA-THA (type 3). Future SRMAs can minimize spin by presenting balanced reporting of efficacy, or lack thereof, in their abstracts and strengthen methodological rigor by consistently reporting study funding sources.

Level of evidence: Level IV, Systematic review of level-I to level-IV studies.