Ludvig Björk, MPBME

​Title of Master thesis: Study of bone anisotropy in porous metallic implants using birefringence and X-ray scattering imaging

Password: 895648

Metallic implants are commonplace in orthopaedic surgery and recent advances in manufacturing technology has made it possible to manufacture 3D printed porous implants.  This allows for designs that are mechanically tailored to fit their environment. Bone growth in porous implants has been previously investigated, but 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 the birefringence microscope is refined using Mueller calculus and the angle of the fast axis and retardance of the sample are analysed. As the region of interest is too large for the microscope field of view, 4 images are stitched using the scale-invariant feature transform and random sample consensus algorithms. The data is validated through correlation with SAXS experiments.  Additionally, 3D reconstruction of SAXS data is performed using real unrestricted spherical harmonic tensor tomography.

The result show that the source of birefringence in bone is from collagen fibres. This is used to show that the fibres outside the area affected by implantation have a preferred orientation along the longitudinal axis, 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.

Examiner: Marianne Liebi  
Supervisor: Marianne Liebi
Opponent: Rafid Kadhim
Category Student project presentation
Location: PJ, seminar room, Fysik Origo, Campus Johanneberg
Starts: 04 October, 2022, 10:30
Ends: 04 October, 2022, 11:30

Page manager Published: Wed 21 Sep 2022.