Comparison of Outcomes Following Total Hip Arthroplasty Between Patients Diagnosed with Association Research Circulation Osseous (ARCO) Stage III and Stage IV Osteonecrosis of the Femoral Head: A Retrospective Study of 302 Patients.

BACKGROUND This retrospective study from a single center aimed to compare outcomes following total hip arthroplasty (THA) in 302 patients diagnosed with Association Research Circulation Osseous (ARCO) stage III and stage IV osteonecrosis of the femoral head (ONFH). MATERIAL AND METHODS The study included 302 patients who underwent THA for ONFH between January 2018 and September 2021. Patient groups included ARCO stage III (n=145) and ARCO stage IV (n=157). Outcomes measured included duration of disease, operative time, intraoperative blood volume, postoperative length of hospital stay, pain measured by the visual analog scale (VAS) score, Harris hip score (HHS), and forgotten joint score (FJS). RESULTS Patients with ARCO stage III ONFH had a significantly shorter operative time (P=0.009), shorter length of hospital stay (P=0.021), and reduced volume of intraoperative bleeding (P=0.021) compared with patients with ARCO stage IV ONFH. There were no significant differences in disease duration (P=0.310), postoperative complications (P=0.07), preoperative (P=0.086, P=0.156) and postoperative (P=0.062, P=0.173) HHS and VAS scores, respectively. Patients with stage III ONFH reported significantly higher FJS scores at 3 months, 6 months, and 1 year after THA. CONCLUSIONS Patients who underwent hip arthroplasty for ARCO stage III femoral head necrosis experienced shorter operative time and hospital stay, less intraoperative bleeding, and better restoration of hip function than those with ARCO stage IV. Moreover, stage III patients were more prone to "forget" their hip arthroplasty experience within 1 year of surgery.