High resolution X-ray imaging of bone-implant interface by large area flat-panel detector

The aim of the research was to investigate the cemented bone-implant interface be- havior (cement layer degradation and bone-cement interface debonding) with emphasis on imaging techniques suitable to detect the early defects in the cement layer. To simulate in vivo conditions a human pelvic bone was implanted with polyurethane acetabular cup using commercial acrylic bone cement. The implanted cup was then loaded in a custom hip simulator to initiate fatigue crack prop- agation in the bone cement. The pelvic bone was then repetitively scanned in a micro-tomography device. Reconstructed tomography images showed failure processes that occurred in the cement layer during the first 250 , 000 cycles. A failure in cemented acetabular implant — debonding, crumbling and smeared cracks — has been found to be at the bone-cement interface. Use of micro-focus source and high resolution flat panel detector of large physical dimensions allowed to r econstruct the micro-structural models suitable for investigation of migration, micro-motions and consecutive loosening of the implant. The large area flat panel detector with physical dimensions 1 20 × 120 mm with 50μm pixel size provided a superior image quality compared to clinical CT systems with 300 − 150 μm pixel size.