Revision total hip arthroplasty using a reconstruction cage device and a cemented dual mobility cup.

INTRODUCTION: The main causes of total hip arthroplasty (THA) revisions are loosening and instability. Dual mobility cups were introduced to prevent instability, but their behavior during revisions with acetabular reconstruction has not been assessed. HYPOTHESES: Use of a dual mobility cup cemented in a acetabular reconstruction cage device limits the risk of instability and does not hinder the acetabular fixation during THA revisions.
OBJECTIVES: The objective of this study was to test this hypothesis on a retrospective series of 96 revisions. PATIENTS AND METHODS: At a mean follow-up of 41 months (range, 1-101 months), we analyzed a continuous series of 96 revisions using a reconstruction device (70 Kerboull™ cross-plates, six Burch-Schneider™ antiprotrusio cages, 20 custom-fit Novae ARM™ cages associated in all cases with a Novae Stick dual mobility cup cemented into the cage). Fifteen patients died at a mean follow-up of 22 months (range, 1-66 months) and four patients were lost to follow-up at a mean follow-up of 16 months (range, 9-27 months). These were acetabular revisons involving major bone loss, with 62 stage III and 26 stage IV cases on the SOFCOT classification. Eighty-seven patients (87.5%) underwent structural bone allografting.
RESULTS: The mean Merle d'Aubigné score increased from 9.6 ± 3.06 (range, 2-16) preoperatively to 15.5 ± 2.32 (range, 7-18) at the follow-up. Ten dislocations (10.4%) occurred, five of which were delayed over three months after the index procedure (5.2%), but there were no intraprosthetic dislocations. At the follow-up, the X-rays showed eight hardware failures, including one cross-plate fracture, one hook fracture, and one flange fracture. Analysis of the radiological position of the cup showed a mean lowering of 15.6mm and a 9.4mm lateralization compared to the preoperative position. One revision for aseptic loosening and another for septic loosening were performed. Taking all-cause acetabular component exchange as a criterion, the survival rate at 8 years was 95.6% (95% CI, 93.3-97.7%) and 99.3% (95% CI, 98.9-99.6%) if the endpoint was aseptic acetabular exchange. DISCUSSION: This study confirms the advantage of dual mobility cups during acetabular reconstruction cemented in antiprotrusio cages as a way to limit, without eliminating, the risk of dislocation. Therefore cemented fixation of dual mobility cups in cages appears to be a reliable short-term option.