International Journal of Computer Assisted Radiology and Surgery https://doi.org/10.1007/s11548-021-02503-0 ORIGINAL ARTICLE Targeting repeatability of a less obtrusive surgical navigation procedure for total shoulder arthroplasty Oded Aminov 1 · William Regan 2 · Joshua W. Giles 3 · Maciej J. K. Simon 4,5 · Antony J. Hodgson 6 Received: 22 April 2021 / Accepted: 17 September 2021 © CARS 2021 Abstract Purpose Surgical navigation systems have demonstrated improvements in alignment accuracy in a number of arthroplasty procedures, but they have not yet been widely adopted for use in total shoulder arthroplasty (TSA). We believe this is due in part to the obtrusiveness of conventional optical tracking systems, as well as the need for additional intraoperative steps such as calibration and registration. The purpose of this study is to evaluate the feasibility of adapting a less-intrusive dental navigation system for use in TSA. Methods We developed a proof-of-concept system based on validated laser-engraved surgical tools recently introduced for use in dental surgery that are calibrated once when manufactured and not recalibrated at time of use. The design also features a notably smaller bone-mounted tracker that can be tracked from a wide range of viewing angles. To assess our system’s performance, we modified the dental surgical software to support guidance of a TSA procedure. We then conducted a user study in which three participants with varying surgical experience used the system to drill 30 holes in a glenoid model. Using a coordinate measuring machine, we determined the resulting drilled trajectory and compared this to the pre-planned trajectory. Since we used a model glenoid rather than anatomical specimens, we report on targeting precision rather than overall procedure precision or accuracy. Results We found targeting precision < 1 mm (standard deviation) for locating the entry hole and < ~ 1° (SD) for both version and inclination. The latter value was markedly lower than the end-to-end angular precision achieved by previously reported TSA navigation systems (approximately 3°–5° SD). Conclusion We conclude that variability during the targeting phase represents a small fraction of the overall variability exhibited by existing systems, so a less obtrusive navigation system for TSA based on laser-engraved tooling is likely feasible, which could improve the uptake rates of surgical navigation for TSA, thereby potentially leading to improved overall surgical outcomes. Keywords Surgical navigation · Total shoulder arthroplasty · Patient-specific instrumentation · Computer-assisted orthopaedic surgery · Orthopaedics B Oded Aminov odedaminov@gmail.com William Regan wregan@mail.ubc.ca Joshua W. Giles jwgiles@uvic.ca Maciej J. K. Simon ma.simon@uke.de Antony J. Hodgson ahodgson@mech.ubc.ca 1 Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada 2 Department of Orthopedics, UBC, Vancouver, BC, Canada 3 Mechanical Engineering, University of Victoria, Victoria, BC, Canada 4 Department of Orthopedics, UBC, Vancouver, BC, Canada 5 Department of Orthopaedic and Trauma Surgery, University Medical Center Schleswig-Holstein - Campus Kiel, Arnold-Heller-Str. 3, 24105 Kiel, Germany 6 Mechanical Engineering, University of British Columbia, Vancouver, BC, Canada 123