Radiographic Analysis of Bone Remodelling Around a Novel 3D-Printed, Highly Porous Titanium Monobloc Dual-Mobility Cup in Total Hip Arthroplasty at 2-Year Follow-Up

Dual-mobility cups (DMCs) are traditionally manufactured from stainless steel or cobalt–chromium, materials with substantially greater stiffness than cancellous bone that may contribute to stress shielding and periacetabular bone resorption. A recently introduced 3D-printed titanium alloy DMC features a highly porous randomized trabecular architecture at the bone–implant interface. This study aimed to compare the short-term radiographic osseointegration and changes in periacetabular relative bone density (RBD) of this novel titanium DMC with those of conventional third-generation DMCs. A total of 204 patients who underwent cementless total hip arthroplasty were retrospectively included. Propensity score matching was used to identify two comparable groups: Titanium (n = 88) and Conventional (n = 88). Radiographic assessment at a minimum of 2-year follow-up included Moore’s signs of osseointegration and the presence of radiolucent lines (RLLs). Relative bone density was measured in three regions of interest (ROIs) around the cup using ImageJ, and percentage changes from the postoperative assessment to the 2-year follow-up were calculated. Both groups demonstrated satisfactory radiographic fixation, with at least three Moore signs present in 100% of the Titanium group and 97.7% of the Conventional group (p = 0.497). No RLLs were observed in the Titanium group at final follow-up, whereas six hips (6.8%) in the Conventional group exhibited RLLs > 2 mm (p = 0.029). Both groups showed decreases in RBD across all ROIs, with no statistically significant between-group differences. At a minimum of 2-year follow-up, the novel 3D-printed titanium DMC demonstrated satisfactory radiographic fixation, with no statistically significant differences in periacetabular RBD compared with the heterogeneous group of conventional DMCs. These preliminary short-term findings require confirmation in prospective studies incorporating validated clinical outcomes, quantitative imaging, and longer follow-up.