Lower 30-day reoperation rate with robotic arm–assisted total hip arthroplasty

Utilization of robotic arm–assisted primary total hip arthroplasty (rTHA) nearly doubled between 2019 and 2024 in public hospitals under the Hong Kong West Cluster (HKWC), and was associated with lower 30- and 90-day reoperation rates vs conventional THA (cTHA), researchers from the University of Hong Kong and Queen Mary Hospital have found.

The retrospective cohort study included all patients who underwent primary THA in HKWC hospitals in 2019–2024. Utilization trends and early outcomes of rTHA vs cTHA were evaluated using data retrieved from the Hospital Authority’s electronic databases. [Hong Kong Med J 2026;32:23-29]

A total of 311 rTHA cases (female, 61.7 percent; mean age, 62.68 years) and 242 cTHA cases (female, 63.6 percent; mean age, 66.10 years) were included in the study. Robotic utilization  increased from 32.0 percent in 2019 to 62.2 percent in 2024, with the highest utilization in 2023 at 75.2 percent.

“These findings indicate a shift in the primary surgical approach within the HKWC, from conventional to robotic techniques,” noted the authors.

Compared with conventional techniques, robotic surgery was associated with a lower 30-day reoperation rate (0.32 vs 2.07 percent; p=0.049). One reoperation due to dislocation was performed in the rTHA group. In the cTHA group, one dislocation, two periprosthetic fractures, and two cases of infection required revision surgery. A lower 90-day reoperation rate was similarly observed for rTHA (0.64 vs 2.48 percent; p=0.072)

Mean operating time (skin-to-skin) for rTHA was 14.6 minutes longer than for cTHA (142.02 vs 127.43 minutes; p=0.002). The authors attributed this difference to system registration, placement of positioning pins, and the procedural learning curve. When rTHA was introduced in Hong Kong in 2019, only one experienced surgeon performed the procedure, which averaged 131 minutes per session. As more surgeons began using the robotic system, average operating time increased over the next 3 years, reflecting a learning-curve effect. Notably, robotic operating time then fell by 11 minutes from 2022 to 2023, and by another 8 minutes to 133.83 minutes in 2024, indicating growing familiarity with the system and possible completion of the learning curve.

There was no significant difference in median length of stay (LoS) in hospital between the rTHA and cTHA groups. The authors suggested that social and cultural factors unrelated to the surgical technique used may have influenced LoS. For example, the smaller and more confined home environments in Hong Kong vs Western/other countries may reduce patients’ willingness or perceived readiness for early discharge. Additionally, cultural and often self-perceived concerns about burdening family members before achieving sufficient functional recovery commonly lead to a more conservative discharge preference, favouring prolonged inpatient care under medical supervision.

The authors concluded that findings from this first local assessment of early rTHA outcomes may provide useful reference data for other centres. They noted that long‑term data are needed to further evaluate trends in operating time and LoS, and to determine how these translate into improved functional outcomes.