Minimum 2-Year Outcome of a Novel Three-Dimensional-Printed Porous Titanium Acetabular Shell for Complex Primary and Revision Total Hip Arthroplasty.

Abstract

Highly porous tantalum shells have been used for over 15 years to manage acetabular bone loss in revision total hip arthroplasty (THA). Recently, a novel three-dimensional (3D)-printed porous titanium shell was developed, mimicking cancellous bone and accommodating variable angle locking screws for enhanced fixation. This study reported on the short-term outcomes of this titanium shell used in complex primary and revision THA with a minimum follow-up of two years. A total of 103 patients received the 3D-printed titanium porous shell, 46 for complex THA (e.g., failed fracture fixation, metastatic disease) and 57 for revision THA. Revision indications included previous periprosthetic joint infection (18 cases), aseptic loosening (21 cases), trunnionosis (two cases), periprosthetic fractures (six cases), instability (four cases), malposition of the cup (four cases), and other causes (two cases). The Paprosky grading system classified acetabular bone loss, and reoperations were recorded. With a mean follow-up of 4.4 years (range, 2.2 to 7.8), patients showed significant functional improvements. The Harris hip score increased from 36.8 ± 17.0 preoperatively to 81.8 ± 14.0 postoperatively (P < 0.001), and Western Ontario and McMaster Universities Osteoarthritis Index scores improved from 46.0 ± 18.2 to 69.8 ± 19.8 (P < 0.001). On average, 5.5 screws per case were used (3.4 locking, 2.0 nonlocking). Titanium augments were used in 10 cases (9.7%). Paprosky grades included type I (23.3%), type IIA (26.2%), type IIB (16.5%), type IIC (8.7%), type IIIA (17.5%), and type IIIB (7.8%). There were 10 reoperations (9.7%), with six for periprosthetic joint infections, two for instability and one each for aseptic loosening of cup and stem. This novel 3D-printed highly porous titanium shell, often used with variable angle locking screws, has provided excellent fixation in a variety of complex primary and revision THAs at a minimum 2-year follow-up. This new shell has demonstrated results comparable to our experience with porous tantalum shells and represents a viable alternative in our institution.