TITLE:
Effects of Hip Arthroplasties on Bone Adaptation in Lower Limbs: A Computational Study
AUTHORS:
Abdul Halim Abdullah, Mitsugu Mitsugu Todo
KEYWORDS:
Lower Limbs, Osteoarthritis, Total Hip Arthroplasty, Resurfacing Hip, Bone Adaptation
JOURNAL NAME:
Journal of Biosciences and Medicines,
Vol.3 No.4,
April
9,
2015
ABSTRACT: Gait disorders contribute to the risk of falls
and successive injuries, especially to elderly populations. The risk of falls
becomes higher for hip osteoarthritis (OA) and hip arthroplasties patients due
to poor balancing and gait impairment. Bone adaptation and bone loss are
fundamental issues in considering the changes of bone behavior and gait
pattern. In this study, computational analysis of the lower limbs was conducted
to estimate the bone adaptation after hip arthroplasties procedure. 3D
inhomogeneous model of lower limb was developed from computed topography (CT- based)
data of 79 years old patient with hip osteoarthritis problem in left limb. Two
types of arthroplaties were constructed in the left limb, namely total hip
arthroplasty and resurfacing hip arthroplasty using commercial biomedical
software, Mechanical Finder v6.1. Prosthesis stem and acetabular cup of THA
were modelled as titanium alloy material (E = 114 GPa, v = 0.34), femoral ball
and bearing insert as alumina properties (E = 370 GPa, v = 0.22). Meanwhile,
RHA implant was assigned as Co-Cr-Mo material (E = 230 GPa, v = 0.30). Contact
between both implants and bone were considered to be perfectly bonded at the
interface. A load case of quiet standing position was conducted in this
analysis with 60 kg of the patients’ body weight. The load was applied at the
cross sectional lumbar vertebra and fixed at the distal of femoral shafts.
Results show different patterns of stress distribution in right and left
(operated) limbs for hip OA, THA and RHA models. An indication of stress alteration
on both limbs after arthroplasties suggested that the bone adaptation occurred.
The higher percentage of change in the left limb projected that the adaptation
was more critical in operated limb.