Implant Survivorships and Complications Among Patients Undergoing Primary Total Hip Arthroplasty for Osteonecrosis Versus Osteoarthritis: Five-Year Minimum Follow-up.

BACKGROUND

Survivorship of total hip arthroplasty (THA) may differ in patients who have osteonecrosis (ON) or osteoarthritis (OA), but this may reflect risk factors known to lead to poor results. This study compared two- and 5-year implant complications, including (1) mechanical complications (dislocation, aseptic loosening, and periprosthetic fracture), (2) periprosthetic joint infections (PJIs), and (3) all-cause revisions, after THA for ON without specified risk factors versus OA.

METHODS

A nationwide database was reviewed from 2010 to 2021 for primary THA with a minimum 5-year follow-up. Exclusions were sickle cell disease, leukemia, active corticosteroid use, human immunodeficiency virus, and genetic diseases. A total of 43,893 patients who had ON were 1:5 ratio-matched to 218,935 patients who had OA by age, sex, and comorbidities, with approximately 85% of each cohort being at least 50 years of age. Outcomes were two- and 5-year implant complications analyzed in cohorts dichotomized by age (less than 50 and at least 50 years). Multivariable logistic regressions computed odds ratios (ORs), with significance defined as P < 0.003.

RESULTS

Osteonecrosis was associated with increased odds of dislocation at two (OR 1.59 to 1.67) and 5 years (OR 1.52 to 1.60) versus OA, regardless of age. In patients aged 50 years and older, ON increased odds of aseptic loosening at two (OR 1.60) and five (OR 1.46) years and periprosthetic fracture at five years (OR 1.41). There was an increased PJI risk at two (OR 1.41) and five (OR 1.43) years, and all-cause revision risk was higher at two (OR 1.68) and five (OR 1.55) years.

CONCLUSIONS

Patients undergoing THA for ON, particularly those older than 50 years, experienced greater odds of dislocation, aseptic loosening, PJI, and revision at five years compared with OA. These data inform expectations for longitudinal implant outcomes by indication.

LEVEL OF EVIDENCE: III.