What Is the Effect of Robot Reduction in Displaced Pelvic Fractures? A Multicenter Randomized Clinical Trial

Displaced pelvic fractures present real surgical challenges because of complex three-dimensional deformity patterns and proximity to vital structures, with conventional manual reduction techniques limited by accuracy constraints and radiation exposure. Although robotic assistance shows promise in preclinical studies, its clinical effectiveness remains unproven in randomized clinical trials (RCTs).

(1) Does robotic closed reduction improve reduction quality compared with manual closed reduction in displaced pelvic fractures? (2) Can robotic closed reduction reduce intraoperative radiation exposure while maintaining functional outcomes?

In this multicenter RCT conducted at six tertiary trauma centers in China involving 10 senior orthopaedic traumatologists, 92 adult patients with acute closed, displaced pelvic fractures (Tile Type B or C) were randomized 1:1 to robotic closed reduction (n = 46) or manual closed reduction (n = 46) groups. At 12 weeks, loss to follow-up for patient-reported outcomes was 9% (4 of 46) in the robotic group and 4% (2 of 46) in the manual group; the remainder were handled in a prespecified per-protocol analysis. In the robot group, reduction was planned using CT-based three-dimensional reconstruction with contralateral pelvic symmetry as the target and executed by a robotic arm with adjunct elastic traction and contralateral pelvic stabilization. In the manual group, reduction was performed using traction and manual manipulation under fluoroscopic guidance. Surgeons and patients were not blinded; radiographic outcome assessors and data analysts were blinded. Primary outcome was reduction quality assessed using Matta criteria (excellent ≤ 4 mm residual displacement, good 5 to 10 mm, acceptable 10 to 20 mm, poor > 20 mm), analyzed as the proportion of excellent to good reductions. Secondary outcomes included intraoperative surgeon fluoroscopic exposure and 12-week Majeed pelvic scores (0 to 100 points across seven domains; higher scores indicate better function). The primary analysis was intention to treat.

In the intention-to-treat analysis, a higher proportion of patients who underwent robotic closed reduction achieved an excellent or good reduction than did those who received manual closed reduction (96% [44 of 46] versus 48% [22 of 46], relative risk 2.00 [95% confidence interval (CI) 1.47 to 2.72]; p < 0.001). Median (IQR) intraoperative surgeon fluoroscopic exposure was lower in the robotic closed reduction group (0 [0 to 0] versus 38 [14 to 78] fluoroscopic exposures; p < 0.001). No differences were found in 12-week Majeed functional scores between groups (mean ± SD 69 ± 16 versus 71 ± 17, mean difference -3 [95% CI -11 to 6]; p = 0.55). One superficial infection occurred in the manual closed reduction group, and there were no serious complications in either group.

Surgeons treating acute displaced pelvic ring fractures should consider robotic closed reduction, when available, to improve reduction quality and reduce intraoperative fluoroscopic exposure, although it did not result in improved patient-reported outcome scores at short term in this randomized trial. Future studies should evaluate longer term functional benefits, define the fracture patterns most likely to benefit, and evaluate implementation factors including learning curve and cost-effectiveness across varied trauma settings.

Level I, therapeutic study.