Highly Porous Metal Revision Cup With a Cemented Dual Mobility Bearing Reduces Instability Following Complex Acetabular Reconstructions: A Minimum Two-Year Follow-Up.

Abstract

The aim of this study was to look at instability following complex acetabular reconstructions using a highly porous metal cup with a cemented dual mobility bearing for the reconstruction of large acetabular defects. The secondary outcomes were survivorship free of aseptic loosening and all-cause revision. We retrospectively reviewed our prospectively collected institutional joint registry to look at patients who had complex or revision total hip arthroplasties involving major acetabular defects (Paprosky 3A and 3B, or pelvic discontinuity) who underwent acetabular reconstruction using a highly porous tantalum hemispherical cup with a stainless steel dual mobility cemented liner. Instability was defined as any hip dislocation requiring closed or open reduction. Survivorship free of aseptic loosening and any-cause reoperation was also assessed. A total of 33 revision THAs in 32 patients were identified with a minimum of a 2-year follow-up and a mean follow-up of 48 months (range, 24 to 84). There were no dislocations in the cohort. The overall implant survivorship for revision, including dislocations, aseptic loosening, and any-cause revisions, was 95% (95% confidence interval: 71 to 97). All clinical outcome scores improved significantly from preoperative scores to the latest follow-up, including the Hip Harris Score, Western Ontario and McMaster Universities Osteoarthritis Index, Short Form-12 Physical and Mental scores. Our series of 33 hips reconstructed using a cemented dual mobility liner within a highly porous metal shell works well to mitigate instability, the most frequent complication seen in these complex reconstructions at short-term follow-up. Our series also confirms low rates of aseptic or all-cause revision at a minimum of two years of follow-up of all patients.