Study of bone anisotropy in porous metal lic implants using birefringence and X ray scattering imaging
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Biomedical engineering (MPBME), MSc
Publicerad
2022
Författare
Björk, Ludvig
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Metallic implants are commonplace in orthopaedic surgery. Recent advances in
manufacturing technology have made it possible to manufacture 3D printed porous
implants. This allows for designs that are mechanically tailored to fit their envi ronment. Bone growth in porous implants has been previously investigated, how ever this thesis studies the anisotropy of bone surrounding porous and non-porous
metallic implants through imaging methods such as birefringence microscopy and
small-angle X-ray scattering (SAXS).
Data from birefringence microscopy is corrected using Mueller calculus and the fast
axis angle and retardance of bone is analysed. As the region of interest is too large
for the microscope field of view, four images are stitched using the scale-invariant fea ture transform and random sample consensus algorithms. The birefringence data is
validated through correlation with SAXS experiments. Additionally, 3D reconstruc tion of SAXS data is performed using real unrestricted spherical harmonic tensor
tomography.
The validation of birefringence data indicates that the source of birefringence in
bone is from collagen fibres. As a result, birefringence microscopy is used to show
that fibres outside the area affected by implantation have a preferred orientation
along the longitudinal axis and fibres inside of the porous implant have a preferred
orientation that correlate with the geometry of the implant. Moreover, around the
perimeter of the implant, bone growth is disordered as some fibres wrap around the
outside of the implant, and some grow into pores. This shows that the geometry of
the implant plays an important role in the anisotropy of bone, which can efficiently
be studied using birefringence microscopy and SAXS
Beskrivning
Ämne/nyckelord
Porous implants, birefringence, collagen, SAXS.