Investigating the Multi-factorial Etiology of Rotator Cuff Pathology in Human Subjects - PROJECT SUMMARY
A rotator cuff tear is a common shoulder condition that affects approximately 40% of individuals over the
age of 60. This condition is painful, debilitating, and reduces quality of life. Despite their prevalence, the
etiology of rotator cuff tears is not fully understood but is generally believed to involve extrinsic factors
(i.e. tendon impingement during shoulder motion), intrinsic factors (i.e. tendon degeneration), and/or
overuse. These factors have been studied extensively in animal models, which have provided support for
each factor contributing to rotator cuff pathology. However, these findings have not yet been confirmed in
human studies largely because of the difficulty in accurately and reliably assessing intrinsic factors and
overuse in humans. Ultimately, understanding the etiology of rotator cuff pathology in humans will remain
difficult without a model that characterizes the role of each factor in rotator cuff pathology. The objectives
of the proposed studies are to: 1) develop a preliminary multivariable model classifying the effects of
extrinsic, intrinsic, and overuse factors on rotator cuff pathology in asymptomatic individuals (K99); 2)
extend the model with additional asymptomatic participants (R00); and 3) expand the model to include
symptomatic participants (R00). Our approach will be to quantify shoulder motion and impingement
(extrinsic factors) via biplane x-ray imaging, rotator cuff degeneration (intrinsic factors) via shear wave
elastography, overuse factors via a novel estimate of lifetime shoulder exposure, and the severity of
rotator cuff pathology via diagnostic imaging. We will investigate the relationship between the etiological
factors and rotator cuff pathology using classification and regression tree analysis. The proposed studies
are the keystone of a career development plan developed to provide the necessary mentorship,
coursework, and research training for me to become an independent and impactful researcher. The
goals of the K99 phase are to: 1) obtain training in advanced methods of biomechanical data collection
and analysis to assess the roles of extrinsic, intrinsic, and overuse factors in the etiology of rotator cuff
pathology; 2) develop a preliminary multivariable model describing the role of extrinsic, intrinsic, and
overuse factors on rotator cuff pathology; and 3) obtain a tenure track position at a respected research-
intensive university. The goals of the R00 phase are to: 1) independently conduct the R00 phase study
by implementing the skills learned during the K99 phase; 2) establish multi-disciplinary research
collaborations with engineers, orthopaedic surgeons, and physical therapists; 3) lead a well-funded and
productive research laboratory; and 4) build upon the K99/R00 research findings to secure independent
R01 funding. Together with the rich research environment at Henry Ford Health System, the proposed
career development plan will ensure that I have a unique skillset to pursue an independent research
career, produce sound and impactful research, and help prepare the next generation of scientists.