¹Charité – Centrum für Muskuloskeletale Chirurgie, Berlin, Deutschland
²University Hospital – London Health Science Centre, London, Kanada

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Objectives and questions: Managing acetabular bone loss in complex primary and revision total hip arthroplasty (THA) presents significant surgical challenges. Highly porous tantalum shells have been the standard for addressing severe bone defects, but recent advancements in 3D-printing technology have led to the development of a fully porous titanium acetabular shell. This novel implant was designed to enhance osseointegration and stability, with variable-angle locking screws to optimize fixation. The purpose of this study is to evaluate the short-term clinical and radiographic outcomes of this 3D-printed titanium shell in complex primary and revision THA, with a minimum two-year follow-up.

Material and methods: A retrospective cohort study was conducted on 103 patients who underwent THA using this 3D-printed porous titanium shell between 2016 and 2021. Of these, 46 patients had complex primary THA (cTHA), and 57 underwent revision THA (rTHA). Revision indications included aseptic loosening (21 cases), prosthetic joint infection (18), periprosthetic fracture (6), instability (4), trunnionosis (2), and malposition (4). Acetabular bone loss was categorized using the Paprosky classification system. Functional outcomes were assessed using the Harris Hip Score (HHS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), while radiographic analysis evaluated osseointegration and implant stability.

Results: With a mean follow-up of 4.4 years (range 2.2–7.8 years), all patients demonstrated significant functional improvements. The HHS improved from 36.8 ± 17.0 to 81.8 ± 14.0 (p<0.001), while WOMAC scores increased from 46.0 ± 18.2 to 69.8 ± 19.8 (p<0.001). The mean number of screws per case was 5.5 (3.4 locking, 2.0 non-locking), and titanium augments were used in 10 cases (9.7%). Radiographic analysis revealed 99.0% osseointegration, with minimal evidence of loosening or migration. A total of 10 reoperations (9.7%) were recorded, primarily due to periprosthetic joint infection (n=6) and aseptic loosening (n=1).

Discussion and conclusion: This 3D-printed porous titanium acetabular shell demonstrated excellent fixation, osseointegration, and early survivorship in both complex primary and revision THA. Functional outcomes were significantly improved, and the implant exhibited stability comparable to traditional porous tantalum alternatives. The integration of variable-angle locking screws may provide additional fixation advantages, particularly in cases with significant acetabular bone loss. These results support the continued adoption of 3D-printed titanium technology for complex acetabular reconstruction, though long-term follow-up is needed to assess its durability over time.