POSTERIOR-BUTTRESS AUGMENTATION IN PAPROSKY TYPE IIIA ACETABULAR DEFECTS: 4-YEAR FOLLOW-UP

Abstract

Revision total hip arthroplasty in the setting of Paprosky type IIIA acetabular defects poses a major surgical challenge because of superolateral bone loss, migration of the hip centre of rotation, and altered hip biomechanics. The aim of this study was to analyse the biomechanical rationale, clinical outcomes, and early functional outcomes of reconstructing Paprosky type IIIA defects using a tantalum buttress augment.

A retrospective analysis was performed of six patients (five women and one man) with a mean age of 69 years and a minimum follow-up of four years. The inclusion criterion was an intraoperatively confirmed Paprosky type IIIA acetabular defect. In four patients, revision was performed according to a two-stage protocol for periprosthetic joint infection, whereas in two it was undertaken for aseptic loosening. Reconstruction was achieved using a tantalum buttress augment in combination with an uncemented tantalum acetabular cup, resulting in a stable monoblock construct.

Clinical assessment using the Harris Hip Score (HHS) demonstrated a 26%-30% improvement at 6 months postoperatively compared with preoperative values, indicating an early functional benefit. At 4-year follow-up, no signs of mechanical instability or radiographic loosening were identified.

These findings confirm that the tantalum buttress augment provides stable primary fixation, reliable osseointegration, and clinically significant functional improvement in the management of Paprosky type IIIA acetabular defects.