Clinical outcomes and learning curve of robot-assisted percutaneous cannulated screw fixation for femoral neck fractures

Background Robot-assisted cannulated-screw fixation may improve trajectory control and reduce fluoroscopic acquisitions during femoral neck fracture treatment; however, its comparative clinical benefits and early learning curve remain insufficiently characterized. Methods This single-centre retrospective cohort study included 61 patients aged 18–65 years with acute Pauwels type II or III femoral neck fractures treated between January 2023 and January 2025. Twenty-one patients underwent robot-assisted fixation and 40 underwent conventional freehand fixation with three cannulated screws. Perioperative, radiographic, and 12-month clinical outcomes were compared. The learning curve was assessed using Spearman rank correlation, simple linear regression, and mean-centred cumulative sum (CUSUM) analysis. Results Baseline characteristics were comparable between groups. Compared with conventional freehand fixation, robot-assisted fixation was associated with shorter total operative time., fewer fluoroscopic acquisitions.., and lower intraoperative blood loss… Robot-assisted fixation was associated with more favourable screw-placement parameters and less femoral-neck shortening. Postoperative day-1 pain scores assessed using VAS were lower in the robot-assisted group. HHS values were higher at 1 month and final follow-up. Fracture-healing time and neck–shaft angle did not differ significantly between groups. Only one postoperative complication occurred during follow-up, consisting of screw back-out in one patient in the freehand group; therefore, comparative safety conclusions were not supported. Within the robot-assisted cohort, case number was inversely associated with total operative time, puncture workflow time, and fluoroscopy use. The mean-centred CUSUM trajectories reached sample-specific maxima at cases 7, 6, and 6, respectively, before showing overall downward trajectories. Conclusion Robot-assisted percutaneous cannulated-screw fixation was associated with greater procedural efficiency and more favourable screw-placement parameters than conventional freehand fixation. Statistically significant differences were observed in postoperative pain, HHS, and femoral-neck shortening; however, the clinical importance of these differences remains uncertain. Operative performance improved across the observed sequence of robot-assisted cases, although no validated proficiency threshold could be established from this cohort.