Fluoro HIP, a new software for intraoperative evaluation of the cup angles based on fluoroscopic images

Purpose

Despite its clinical benefits, intraoperative navigation is currently used only in approximately 20% of total hip arthroplasties (THA) partly due to the high cost of the systems and time-consuming preoperative preparation. By providing a simpler and less expensive alternative, the use of intraoperative navigation is likely to increase among surgeons. In this study, we sought to validate the accuracy and utility of Fluoro HIP, a newly developed cup angle measurement software that runs on iOS devices.

Methods

Twenty-seven patients who underwent primary total hip arthroplasty between June and September 2022 were included in the study. All patients underwent surgery in the supine position. Inclination and anteversion angles were determined using Fluoro HIP software based on the fluoroscopic images captured during surgery. Navigation errors were calculated by comparing with the values obtained from postoperative CT images.

Results

The inclination and anteversion angles measured were 38.7 ​± ​3.9 and 15.0 ​± ​3.1°, respectively. The absolute value errors were 2.7 ​± ​1.9 and 3.0 ​± ​2.1° for the inclination and anteversion, respectively. Although Fluoro HIP software-based system may not be as precise as the conventional CT-based or portable navigation systems, the intraoperative evaluation of the cup angles by this system was considered to have acceptable accuracy and reproducibility for most THA cases performed in the supine position. Most importantly, our system requires no preoperative preparation and is significantly less expensive than other types of navigation systems currently in use.

Conclusion

The Fluoro HIP software-based system is a highly cost-effective and affordable alternative to the conventional navigation systems.