Porous Tantalum Acetabular Components in Complex Revision Total Hip Arthroplasty: The Influence of Defect Severity and Intraoperative Fixation.

BACKGROUND: Porous tantalum acetabular components are widely used in revision total hip arthroplasty (rTHA) to manage acetabular bone loss. Re-revision risk according to defect severity and intraoperative fixation is poorly characterized.

METHODS: Between 2003 and 2024, 316 patients (345 hips) underwent rTHA surgery, who were treated with a porous tantalum acetabular component. Of these hips, 212 (61.4%) were in women. Mean age at surgery was 71 years (range, 26 to 95), and mean follow-up was 6.5 years (range, zero to 21.9). The primary endpoint was acetabular re-revision for aseptic loosening; the secondary endpoint was all-cause acetabular re-revision. Cumulative incidence functions estimated risk at two, five, and 10 years; associations were assessed using subdistribution hazard ratios (sHR). Analyses were stratified by Paprosky defect, pelvic discontinuity (PD), and intraoperative fixation (press-fit and/or three-point). Paprosky grades were 2A (n = 36), 2B (n = 68), 2C (n = 82), 3A (n = 105), and 3B (n = 54); 82 hips had PD (23.8%).

RESULTS: Cumulative incidence of re-revision for aseptic loosening was 0.87, 1.84, and 2.72% at two, five, and 10 years, respectively; corresponding all-cause re-revision estimates were 5.52, 7.40, and 9.23%. Paprosky grade was not associated with re-revision risk. Undergoing a third or greater rTHA was associated with increased failure risk (sHR 2.69, P = 0.03). Press-fit and/or three-point fixation were associated with reduced re-revision risk in univariable analysis; however, only three-point fixation remained independently associated with reduced re-revision risk (sHR 0.37, P = 0.04), whereas press-fit fixation was not independently associated with re-revision after adjustment.

CONCLUSION: Porous tantalum acetabular components achieve excellent re-revision outcomes from two to 10 years after rTHA, with low rates of aseptic loosening across all defect grades. Greater prior revision burden and failure to achieve three-point fixation were independently associated with increased re-revision risk.