S. McPhee; M.P. Fernández; L. Koria; M. Mengoni; R.J. Beck; J.D. Shephard; C. Brockett; U. Wolfram
arXiv (2025) 2510.17824
Osteoarthritis (OA) is a multifaceted joint disease which poses significant socioeconomic
burdens and remains a significant clinical challenge. Evidence suggests that structural and me-
chanical changes in subchondral bone influence the pathogenesis and development of OA,
leading to diminished bone quality and cartilage degeneration. While changes in microstruc-
ture and tissue scale elastic properties are well reported, the tissue yield response of subchon-
dral bone in OA and their correlation with compositional changes have not been investigated.
Here, we performed quasistatic micropillar compression and nanoindentation within the sub-
chondral bone plate and trabeculae of hydrated non-diseased (ND) and OA affected speci-
mens retrieved from the distal tibia in vivo. The micropillars, extracted by laser ablation, exhib-
ited a taper angle which mandated the use of an in silico micropillar compression routine to
back-calculate elastic modulus and strength of the bone tissue that comprised each micropil-
lar. Elastic modulus remained unchanged between ND and OA subchondral bone, whereas
strength increased from 46.0 MPa to 57.3 MPa in OA subchondral trabecular bone but not in
the bone plate. Micropillar matched Raman spectroscopy and quantitative backscattered elec-
tron imaging revealed mineralisation is the underlying determinant of elastic modulus and
strength at the microscale. By combining micromechanical and tissue compositional analyses,
we investigated how the mechanical properties are related and how these properties are af-
fected in subchondral bone by OA. Our results may be of value in the development and opti-
misation of interventions used to alleviate the socioeconomic burdens associated with this
debilitating joint disease.
DOI: https://doi.org/10.48550/arXiv.2510.17824