Long Term Clinical and Radiographic Osseointegration Outcomes of a Highly Porous 3D Printed Titanium Collar for Megaprostheses Compared to a Previous Generation Ha Coated Collar

Achieving stable bone integration in megaprosthetic reconstructions remains challenging, with traditional hydroxyapatite (HA)-coated collars showing variable outcomes. This study compares long-term osseointegration and clinical performance of a novel 3D-printed porous collar (EPORE®) versus conventional HA-coated collars in 52 patients (28 with 3D-printed, 24 with HA-coated). Radiographic osseointegration was assessed using a validated scoring system, with follow-up exceeding two years. The 3D-printed group demonstrated significantly higher osseointegration rates (92.9% vs. 70.8%, p=0.04) and faster bone ongrowth (470 vs. 1482 days to full integration, p<0.0001), with 89.3% achieving the highest integration score compared to 37.5% in the HA group (p=0.0002). Notably, no aseptic loosening occurred with 3D-printed collars, while HA-coated collars had an 8% aseptic loosening rate. Despite higher BMI in the 3D-printed group (32.5 vs. 28.4, p=0.01), outcomes were superior, suggesting the porous design mitigates obesity-related risks. These findings indicate that 3D-printed collars enhance biological fixation, reduce loosening, and improve implant stability, particularly in complex revisions. This technology represents a significant advancement in megaprosthetic design, with potential to improve long-term outcomes in high-risk patients.