Integrated mechano-arthroscope for minimally invasive assessment of joint pathologies

About This Grant

Project Summary/Abstract The objective of this project is to develop and evaluate the feasibility of an integrated mechano-arthroscope for minimally invasive assessment of joint tissue pathology and micromechanics. Joint tissues, such as cartilage and meniscus, perform crucial mechanical function of bearing and dissipating loads imparted upon the joints. To support this functional role, joint tissues possess specialized solid and liquid extracellular matrix constituents that provide the necessary interplays of elastic stiffness and viscous dissipative behaviors. Degenerative joint disease (arthritis) disrupts these intricately designed mechanical machineries, directly degrading tissue function, causing pain and reduced mobility. Arthritis is a global health crisis that affects more than 500 million people worldwide, with prevalence and years lived with disability attributable to the disease projected to continue to rise. This crisis is exacerbated by the fact that an effective cure is yet to be found. A fundamental roadblock in the medical treatment of arthritis is the lack of effective ways to assess the deficiencies of joint tissues and their restoration of functional integrity following treatments in living patients. Despite mechanics being the direct determinant of function, current diagnostic paradigm for joint pathologies does not, in fact, include any direct measures of the mechanical quality of joint tissues. Diagnostic imaging provides structural metrics such as joint space narrowing and cartilage lesion size, while arthroscopy, the gold standard for grading cartilage defects and repair, provides visualization of gross appearance and manual palpation of intra-articular structures. This does not allow orthopedic surgeons to precisely evaluate the functional mechanical integrity of joint tissues to guide surgical treatments and monitor the status of tissue repair and healing following treatments. This gap not only hinders the direct medical care of patients with joint pathologies, but also severely restricts the development of effective therapies on a larger scale due to the absence of crucial mechanical outcome measures in living patients. This project directly addresses this critical gap. We propose to develop a new imaging tool termed ArthSHEAR, in the form of a needle-sized integrated mechano-arthroscope, that will permit minimally invasive assessment of both gross appearance and underlying micromechanical properties of intra-articular tissues in the doctor’s office. ArthSHEAR is based on the core technology of Speckle rHEologicAl microscopy (SHEAR) that enables passive, noncontact mapping of viscoelastic behavior in gross tissues without indenting or otherwise manipulating the sample. The first phase of project will develop and validate the ArthSHEAR instrument and data processing algorithms to permit arthroscopic mapping of the indices of mechanical firmness and viscous dissipation. The second phase will conduct an in vivo longitudinal imaging study in a swine model of osteoarthritis (OA) to evaluate the feasibility of ArthSHEAR for discerning and tracking the micromechanical changes due to degenerative disease. This study will provide the first in vivo longitudinal data that tracks micromechanical transformation over the full course of OA progression from healthy to complete joint damage.