Robotic-Arm Assisted Direct Anterior Approach Total Hip Arthroplasty Facilitates Tensor Fasciae Latae Preservation and Early Functional Recovery in Obese Patients.

OBJECTIVE

This study aimed to evaluate the efficacy and safety of robotic-arm assisted (RA) direct anterior approach (DAA) total hip arthroplasty (THA) in facilitating tensor fasciae latae (TFL) preservation and subsequent functional recovery, and to explore the correlation between TFL preservation and postoperative inflammation, pain, and early functional recovery in obese patients.

METHODS

We retrospectively reviewed 69 obese patients (BMI ≥ 30 kg/m2) undergoing primary DAA-THA from September 2023 to December 2024 with 12-month follow-up. Surgical procedures were performed by RA technology in 31 patients (RA group) and manual technology in 38 patients (M group). Demographic characteristics, perioperative parameters, TFL injury index, unsupported ambulation duration, creatine kinase (CK), C-reactive protein (CRP), Visual Analog Scale scores (VASs), Harris Hip Scores (HHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Forgotten Joint Score-12 (FJS-12), radiologic measurements, and complications were retrieved from patients. Student's t-test and Mann-Whitney U test were used to compare continuous data. Fisher test and Chi-square test were used to compare the categorical data. Longitudinal data were evaluated by generalized estimating equations. The relationships between TFL injury index and early clinical outcomes were evaluated using Spearman's correlation analysis.

RESULTS

Baseline demographic characteristics of both groups were comparable. RA group demonstrated significantly lower TFL injury index (18.05 [IQR 14.51-30.05] % vs. 38.31 [IQR 20.58-50.70] %, p = 0.001) and shorter unsupported ambulation duration (3.00 [IQR 2.00-4.00] week vs. 5.00 [IQR 3.00-6.00] week, p < 0.001) compared to M group. Besides, TFL injury index showed a strong positive correlation with unsupported ambulation duration (ρ = 0.775) (p < 0.001). Compared to M group, RA group significantly reduced CK, CRP, and VASs at the initial 72 h postoperatively (all p < 0.05). RA group exhibited significantly superior HHS, WOMAC, and FJS-12 compared to M group at postoperative 1 month (all p < 0.01). TFL injury index demonstrated strong positive correlations with CK (ρ = 0.619), CRP (ρ = 0.628), and VASs (ρ = 0.652) at postoperative 72 h (all p < 0.001). Furthermore, it showed a strong negative correlation with HHS (ρ = -0.615) and FJS-12 (ρ = -0.759), and moderate positive correlations with WOMAC-pain (ρ = 0.410) and WOMAC-function (ρ = 0.583) at postoperative 1 month (all p < 0.001). Despite longer operative duration in RA group, it exhibited a significantly higher proportion of acetabular components positioned within the Lewinnek safe zone and a significantly lower incidence of incision-related adverse events compared to M group (all p < 0.05).

CONCLUSION

In obese patients undergoing DAA-THA, RA technology significantly reduced intraoperative injury to TFL. This muscle preservation effect was significantly associated with attenuated early postoperative inflammation, lower pain levels, and faster functional recovery.