Cup-on-cup technique: a reliable management solution for severe acetabular bone loss in revision total hip replacement

The management of acetabular bone loss is a challenging problem in revision total hip arthroplasty (rTHA). The goals of treatment are a stable acetabular fixation, implant stability, and restoration of hip centre of rotation.This study aims to report clinical, radiological outcomes and complications at short-term to mid-term follow-up of the cup-on-cup technique in the management of severe acetabular bone loss in rTHA.We retrospectively reviewed the records of patient receiving rTHA performed with double porous tantalum cup technique in a single Joint Replacement Unit from 2014 to 2017. Objective and subjective clinical scores (Harris Hip Score, Oxford Hip Score, and visual analogue scale), radiological parameters (centre of rotation, leg-length discrepancy, heterotopic ossification, osseointegration, loosening and radiolucencies) and complications were recorded. We analysed the implant survival rate and periprosthetic joint infection rate.We included 9 patients (9 hips) with a mean follow-up of 35.3 ± 10.8 months. Functional scores showed a statistically significant improvement at the final follow-up (p < 0.01). All patients rated their surgery as satisfactory. The cup-on-cup construct demonstrated radiological osseointegration with the centre of rotation restoration and leg length discrepancy improvement. In 1 patient, periprosthetic joint infection was diagnosed and treated with suppressive antibiotic therapy. No patients underwent acetabular components revision surgery for any reason.Cup-on-cup technique is a valid and safe solution for reconstruction of selected Paprosky type IIIA and IIIB bone defects with satisfactory clinical and radiographic results at short-term and mid-term follow-up.