Prevalence and Implications of Incidental Findings on Computed Tomography Scans Performed for Mako Robotic Arm-Assisted Joint Arthroplasty

Background: Robotic arm-assisted joint arthroplasty has seen an increase in its popularity internationally. Image-based systems, such as the Mako robotic arm-assisted system, require a preoperative computed tomography (CT) scan to be performed. These scans may detect incidental findings, which can place additional burden on both patients and healthcare providers. Methods: A retrospective cohort study was performed to quantify the prevalence and significance of orthopaedic and nonorthopaedic incidental findings on CT scans obtained using the Mako CT protocol. All preoperative CT scans performed using this protocol between December 2018 and December 2024 for patients undergoing elective primary joint arthroplasty at the institution were included. Clinically significant findings were defined as any new and unexpected results which required invasive workup, surgical management, or had a direct negative impact on life expectancy. Results: Of 1,446 CT reports reviewed, 738 (51.0%) contained 1 or more incidental findings. Rates were highest in the total hip arthroplasty (THA) cohort (71.1%), followed by the unicompartmental knee arthroplasty cohort (51.4%) and total knee arthroplasty (TKA) cohort (42.7%). Only 4 (0.3%) incidental findings were deemed clinically significant, all within the TKA cohort. These findings led to surgical delay in 2 cases and cancellation in 1 case. Conclusion: Incidental findings are common in preoperative CT scans performed for Mako robotic arm-assisted joint arthroplasty, particularly in THA patients. However, clinically significant findings are rare and infrequently alter surgical time frames. Surgeons should remain aware of the potential ethical and medicolegal implications of these findings. Level of Evidence: Level IV, Diagnostic. See Instructions for Authors for a complete description of levels of evidence.