How Much Benefit Can Robot-Assisted Total Hip Arthroplasty Provide for Patients with Severe Hip Dislocation? -a Propensity Score-Matched Analysis

Background Severe hip dislocation caused by various reasons poses significant challenges to total hip replacement(THA)surgery. The application value of robot-assisted THA in such diseases is still unclear. This propensity score-matched study aimed to compare the early outcomes of robot-assisted THA (RaTHA) versus manual THA (MTHA) in patients with severe hip dislocations (Crowe type III/IV). Patients and Methods Patients undergoing THA for severe dislocations were prospectively enrolled, and thier data were collected. Using propensity score matching (based on age, sex, BMI, Crowe classification, and comorbidities), patients were allocated into matched RaTHA and MTHA cohorts. The groups were compared at 12 months postoperatively regarding perioperative indicators, radiographic assessments, functional outcomes (Harris Hip Score, HHS), and complication rates. Results After matching, 29 MTHA and 33 RaTHA patients were finally analyzed. RaTHA was associated with a significantly longer operative time ( P  = 0.042), longer preoperative length of stay (LOS)( P  = 0.032), and higher hospitalization costs ( P  = 0.008) compared to MTHA. Postoperative LOS was similar between the groups. Preoperative HHS were comparable, whereas the RaTHA group showed no significantly higher HHS at 12 months postoperatively ( P  = 0.081). The variability in cup positioning (standard deviation) was lower in the RaTHA group for both inclination (4.7° vs. 8.1°) and anteversion (4.6° vs. 8.6°). However, no statistically significant differences were observed in mean cup inclination or anteversion angles, limb length discrepancy (LLD), or femoral and acetabular offset gaps ( P  > 0.05). Regarding complications, two patients in the RaTHA group experienced dislocations at 3 or 4 months postoperatively, while six patients in the MTHA group had iatrogenic acetabular defects. Both groups reported two cases of postoperative symptoms of femoral nerve palsy. Conclusion For complex and anatomically variable bone structures, robotic technology offered an advantage in procedural consistency, effectively reducing the risk of excessive bone loss. Nevertheless, its impact on shortly functional outcomes, dislocation rates, and economic burden did not currently support a definitive recommendation for its widespread use. Level of evidence Level Ⅱ.