A Comparison between the Enhanced and Express Femoral Workflow for Robot-Assisted Total Hip Arthroplasty: A Self-controlled Observational Study

Purpose: The aim of this prospected comparison study was to compare the enhanced workflow and express workflow for Mako robot-assisted total hip arthroplasty. Method: From February 2020 to December 2020, 26 patients (43 hips) underwent primary robot-assisted total hip arthroplasty. There were 14 male and 12 female patients. The mean age at surgery was 53.5±13.6 years. The enhanced workflow and express workflow were performed separately in robot-assisted total hip arthroplasty on the same hip. The between-group operating time, hip length change, and combined offset were compared. Differences were considered statistically significant at p <0.05. Result: The operating time with the enhanced and express registrations were 73.3±14.1 minutes and 68.8±12.8 minutes, respectively ( p= 0.001). The accuracy of the mean hip length change between the intraoperative trailing implantation and preoperative plan were 1.6±6.9 mm and -0.5±3.1 mm, respectively ( p =0.029). The accuracy of the mean hip length change between the intraoperative prosthesis implantation and preoperative plan were 0.8±5.4 mm and -0.7±3.2 mm, respectively ( p =0.025). Regarding the accuracy of the mean preoperative and intraoperative combined offsets, there were no significant differences between the two registrations ( p >0.05). Conclusion: In comparison, the enhanced registration for robot-assisted total hip arthroplasty is more time-consuming than the express registration. However, the enhanced registration is more accurate than the express registration in assessing limb length discrepancy. Both registrations produce the similar accuracy of the combined offset.