A retrospective cohort study comparing combined TiRobot navigation and percutaneous minimally invasive FNS fixation versus conventional open reduction FNS for femoral neck fractures.

Femoral neck fractures are prone to mechanical failure and severe complications due to high inter-fragmentary shear forces. The Femoral Neck System (FNS) provides angular-stable biomechanical fixation, where precise intra-osseous implant positioning directly determines long-term clinical outcomes. Ti-Robot orthopedic navigation enables preoperative three-dimensional trajectory planning and intra-operative guided screw placement, which may improve implant accuracy while reducing surgical soft tissue trauma. A critical methodological caveat applies to this comparison: the two surgical arms differ simultaneously in navigation modality, fracture reduction technique, and soft tissue dissection extent; observed intergroup outcomes cannot be attributed solely to robotic technology. To compare intra-operative efficiency, fluoroscopic radiation burden, postoperative CT-verified implant precision, 6, 12, and 18-month hip functional recovery, and adverse complication profiles between combined Ti-Robot-guided closed percutaneous FNS fixation and conventional open reduction freehand FNS fixation for femoral neck fractures. This single-center retrospective consecutive cohort study enrolled 80 patients aged 18-65 years with femoral neck fractures treated between January 2023 and December 2024; 40 patients underwent Ti-Robot-assisted percutaneous FNS fixation, and 40 received conventional open reduction FNS fixation. Primary outcome measure was the Harris Hip Score (HHS) collected at 6, 12, and 18 months postoperatively. Secondary outcomes included total operative duration, intra-operative blood loss, fluoroscopic imaging metrics (total shot count + cumulative screening time), postoperative CT implant trajectory deviation, bolt angular parallelism error, first-attempt screw placement success rate, serial 0-10 VAS pain scores, institutional hospital length of stay (LOS), and 18-month fracture-related complication incidence. All participants completed full 18-month clinical and imaging follow-up. Statistical analyses were performed using Python; normality-directed variable-specific testing was applied, with no formal correction conducted for multiple secondary outcome comparisons. Patients treated with Ti-Robot-guided percutaneous fixation demonstrated statistically superior HHS values at all three 6/12/18-month follow-up time intervals (all p < 0.05). Median postoperative CT-measured FNS bolt deviation from a unified blinded radiologist-defined femoral neck central reference axis was 0.9 mm in the robotic cohort versus 1.9 mm in the conventional open cohort (p < 0.001). The robotic group exhibited drastically reduced fluoroscopic shot counts and cumulative screening time, alongside significantly shortened median operative duration (67.0 min vs. 88.0 min; p < 0.001). Intraoperative blood loss was numerically lower in robotic patients without reaching statistical significance (p = 0.160). Serial postoperative VAS pain scores were markedly reduced across all follow-up intervals for the percutaneous robotic group. Hospital LOS followed fixed institutional discharge protocols: all robotic patients were discharged on postoperative day 3, and all open-surgery patients on day 5 (p < 0.001); this near-zero inter-patient variance represents an administrative pathway artifact rather than a marker of individual clinical recovery. While the robotic cohort showed numerical reductions in screw loosening, non-union, and femoral head avascular necrosis (AVN) events at 18 months, all between-group differences for these rare complications lacked statistical significance due to limited sample power. The combined workflow of TiRobot three-dimensional navigation and percutaneous minimally invasive FNS fixation delivers superior implant placement precision, lower intraoperative fluoroscopic radiation exposure, shorter operative time, and sustained mid-term hip functional recovery across the 6, 12, and 18-month follow-up intervals relative to conventional open reduction FNS fixation for Pauwels type III femoral neck fractures. All observed intergroup differences reflect a composite effect of robotic guidance and limited soft tissue dissection. Future standardized randomized controlled trials utilizing identical closed percutaneous approaches in both robotic and freehand arms are required to isolate clinical benefits uniquely attributable to TiRobot navigation.