Effect of Patient Age on Total Hip Arthroplasty Outcomes in Patients Who Have Osteonecrosis of the Femoral Head Compared to Patients Who Have Hip Osteoarthritis

Background: Osteonecrosis of the femoral head (ONFH) affects both young and old patients. However, outcomes following total hip arthroplasty (THA) for these patients may vary with age. This study aimed to examine the effect of age on THA outcomes for non-traumatic ONFH patients, an area currently lacking research. Methods: Patients who had non-traumatic ONFH undergoing THA with at least 2 years of follow-up were identified using a database and divided into four groups by age. Then, 4 matched control groups of patients who had hip osteoarthritis (OA) were created. Multivariate logistic regression analyses were used to evaluate the rates of medical and surgical complications. Additionally, cohorts with a minimum 5-year follow-up were filtered to obtain further data on surgical outcomes. The study analyzed 85,462 non-traumatic ONFH and 80,120 hip OA patients undergoing THA. Results: Multiple medical complications in ONFH patients increased with age. Periprosthetic fracture within 2 years increased with age, while 90-day wound complications, 2-year periprosthetic joint infections, dislocations, and revisions decreased. The trends for complications continued at the 5-year follow-up. Compared to OA patients, those who had ONFH had higher risks of most complications, but this discrepancy decreased with age. Conclusions: In ONFH patients undergoing THA, medical complications generally rise with age, while most surgical complications, including revisions, decrease. It is notable that ONFH patients experienced more complications than those who had OA, but this difference diminished with age.