Abstract
Introduction
Trabecular Titanium™ is a highly porous biomaterial with a regular hexagonal cell structure, which has shown excellent mechanical properties. Several in vitro studies reported promising data on its osteoinductive and osteoconductive properties. Furthermore, it has demonstrated in vivo to enhance bone in-growth. Aim of this multicentre prospective study was to assess Trabecular Titanium™ osseointegration by measuring change in bone mineral density (BMD) around a cementless DELTA-TT cup with dual-emission X-ray absorptiometry (DXA).
Methods
89 patients (91 hips) underwent primary THA with DELTA-TT cups (Lima Corporate) between 2009 and 2010. There were 46 (52%) men and 43 (48%) women, with a median (IQR) age of 67 (57–70) years and a median (IQR) BMI of 26 (24–29) kg/m2. Right side and left side were affected in 44 (48%) and 47 (52%) cases, respectively. Underlying pathology was primary osteoarthritis in 80 (88%) cases, osteonecrosis in 5 (6%), post-traumatic osteoarthritis in 3 (3%), developmental dysplasia of the hip in 2 (2%) and oligoarthritis in 1 (1%). BMD was determined by DXA using DeLee and Charnley 3 Regions of Interest (ROI) at 7 days, 3, 6, 12 and 24 months. Clinical evaluation (Harris Hip Score, HHS), patient health status survey (SF-36) and radiographic assessment were performed preoperatively and at the same time-points. Data were analyzed using non-parametric tests (Mann-Whitney, Wilcoxon signed-rank) and a p < 0.05 as threshold for statistical significance.
Results
Excellent results were observed in terms of pain relief and functional recovery. Median (IQR) HHS improved from 48 (39–62) before surgery, to 99 (96–100) at 24 months, with a statistical significant increase of 96% (p < 0.05, Wilcoxon signed-rank). Median (IQR) SF-36 improved from 49 (37–62) preoperatively to 86 (79–92) at 24 months, with a statistical significant increase of 95% (p < 0.05, Wilcoxon signed-rank), indicating a considerable improvement in patients' quality of life. After an initial decrease of BMD values from baseline at 7 days (median [IQR] ROI I: 1.44 [1.21–1.67]; ROI II: 1.23 [0.99–1.49]; ROI III: 1.11 [0.85–1.48] g/cm2) to 6 months (ROI I: 1.27 [1.08–1.52]; ROI II: 1.14 [0.89–1.37]; ROI III: 1.05 [0.73–1.35] g/cm2), BMD slightly increased in ROI I, the most loaded area, and stabilized in ROI III. BMD in ROI II increased after 12 months and stabilized at 24 months (ROI I: 1.30 [1.11–1.55]; ROI II: 1.12 [0.96–1.36]; ROI III: 1.04 [0.80–1.25] g/cm2). Radiographic analysis showed evident signs of bone remodeling and osseointegration, with presence of supero-lateral and infero-medial bone buttress and of radial trabeculae perpendicular to the cup surface in ROI I/II. No radiolucent lines, loosening or osteolysis were observed. All cups were stable and no revision was carried out.
Conclusion
BMD patterns and radiographic evaluation showed signs of an effective osseointegration around DELTA-TT cups at 24 months. Although clinical outcomes, functional recovery and stability are very satisfactory, longer follow-ups are necessary to assess survivorship.
