Risk factors for allogeneic transfusion in young adults undergoing simultaneous bilateral direct anterior total hip arthroplasty within an ERAS framework.

BACKGROUND

Simultaneous bilateral total hip arthroplasty (SBTHA) under enhanced recovery after surgery (ERAS) can reduce bleeding, yet transfusion remains a limiting factor in young Indian patients with osteonecrosis of femoral head (ONFH), who frequently present with low baseline hemoglobin (Hb). Cohort-specific, actionable thresholds are underreported. Hence, we aimed to quantify transfusion incidence and identify predictors of allogeneic transfusion in young ONFH patients undergoing SBTHA via the direct anterior approach (DAA) within a uniform ERAS protocol.

METHODS

We retrospectively reviewed 75 consecutive ONFH patients (mean age 29.7 ± 6.5 years; 73.3% male) who underwent SBTHA-DAA between January and December 2023. Medical records showed that all patients were managed under routine ERAS protocols (neuraxial anesthesia with controlled hypotension, tranexamic acid, multimodal analgesia, early oral intake and mobilization, and restrictive transfusion triggers). The primary outcome was in-hospital allogeneic transfusion. Logistic regression was used to identify independent predictors of allogeneic transfusion. Receiver operating characteristic analysis with Youden's index was used to determine an optimal preoperative Hb threshold.

RESULTS

The mean postoperative Hb was 10.6 ± 1.8 g/dL, and 17 patients (22.7 percent) required allogeneic transfusion, totaling 18 units. Transfusion recipients had significantly lower preoperative Hb (11.46 g/dL; 95 percent CI 10.35-12.57) than non-transfusion patients (13.20 g/dL; 95 percent CI 12.77-13.64). ROC analysis yielded an AUC of 0.86 and identified 11.9 g/dL as the optimal cutoff, supporting a practical threshold of 12 g/dL (sensitivity 94.1 percent; NPV 98 percent). Length of stay averaged 1.8 days, with no major complications or readmissions. Functional scores improved substantially at one year across all measures.

CONCLUSION

Preoperative Hb level was the sole independent predictor of allogeneic transfusion risk under a standardized ERAS-guided bilateral DAA-THA pathway. These findings support routine anemia screening and correction before surgery to reduce transfusion dependence in this young ONFH cohort.