PROJECT SUMMARY
The overarching objective of this proposal is to determine if transfemoral osseointegrated prostheses have
a positive influence on the etiology of hip osteoarthritis (OA). The two leading causes of disability following
transfemoral amputation are chronic skin pathologies due to poor socket fit (e.g., ulceration) and OA due to
habitually altered joint loading. Osseointegrated prostheses are a recent clinical intervention to treat socket
related pathologies by directly mounting the prosthesis to the residual limb through a bone anchored implant,
providing a more normative load transmission from the ground to residual limb. This proposal will determine if
this improved load transmission has positive role on the pathogenesis of hip OA differently than socket
prostheses. This will be accomplished through a longitudinal study design that will compare the most common
biomechanical etiological factors to OA progression at two timepoints (baseline and 12-months) between two
groups (patients with osseointegrated prostheses and patients who successfully use a traditional socket
prosthesis). In Aim 1, we will quantify bilateral hip muscle quality using fat fraction quantitative magnetic
resonance imaging (MRI). Using these images, we will quantify 3D muscle volume and levels of fatty infiltration
on the bilateral hip musculature. This will elucidate if the known atrophy and poor composition due to disuse in
a socket prosthesis, both of which are known to progress OA, can be reversed following prosthesis
osseointegration. In Aim 2, we will quantify dynamic cartilage loading mechanics using motion capture and a
subject-specific musculoskeletal contact model. Because altered cartilage loading is a primary instigator and
factor in OA onset and progression, these results will determine if cartilage mechanics are normalized during
activities of daily living following osseointegration. Although muscle composition and cartilage mechanics are
etiological factors to OA development, we seek to assess the role of osseointegration on the clinical progression
of OA. Thus, in Aim 3, we will quantify cartilage health using T2 quantitative MRI, which is currently the most
sensitive methodology to assess early osteoarthritic changes in-vivo. Ultimately, we seek to use our multi-domain
approach to better inform targeted interventions aimed at improving outcomes following osseointegration.
The candidate’s overarching career goal is to utilize engineering-based tools to better elucidate the
mechanisms to secondary pain conditions that can be used to improve targeted interventions. This proposal
builds on the candidate’s current expertise by providing new training in quantitative MRI, advanced imaging post-
processing tools, longitudinal research design and implementation, and links between biomechanics and clinical
factors of joint disease. The mentoring team consists of physical therapists, radiologists, bioengineers, and
orthopaedic surgeons who are experts in imaging, clinical interventions, and OA. This proposal will provide
preliminary data for an R01 focused on key factors that affect long-term outcomes with varying prosthesis types.