Contemporary Survivorship of Highly Porous Hemispherical Shells in Aseptic Acetabular Revision Total Hip Arthroplasty

Contemporary performance of revision hemispherical shells in acetabular revision total hip arthroplasty (rTHA) remains limited. This study evaluated survivorship free from revision for aseptic acetabular loosening, all-cause revision, and all-cause reoperation, as well as dislocation rate and patient-reported outcomes (PROMs) following aseptic rTHA with modern, highly-porous, revision acetabular components.

We identified 127 patients (mean age 66, mean body mass index 27, 57% female) who underwent aseptic rTHA with hemispherical shells from 2016 to 2022 with minimum 2-year potential follow-up. Paprosky defects type was I in 20%, II in 70%, and III in 10%. Cases using augments or cages were excluded. A posterolateral approach was used in 98% of patients, and 21% of patients underwent concomitant femoral revision. A mean of 3 (range, 0-5) screws were used. Liners included dual mobility (n = 94), elevated (n = 15), neutral (n = 12), constrained (n = 4), and offset (n = 2). Kaplan-Meier survivorship analysis assessed time-to-event outcomes.

At 2 years, survivorship free from revision for aseptic acetabular loosening was 97%, and free from all-cause revision was 94%. Revision indications included dislocation (n = 4), aseptic loosening (n = 2), periprosthetic joint infection (n = 1), and metallosis (n = 1). Dislocation occurred in 7 patients (6%). At 2 years, there was a median 21.4-point increase in the Hip Injury and Osteoarthritis Outcome Score for Joint Replacement (P < .001).

Modern, highly-porous revision hemispherical shells with multiple screw fixation have excellent 2-year survivorship free from aseptic loosening (97%) but modest dislocation rate (6%). These results support the use of contemporary hemispherical shells but highlight the need for instability prevention.