Advancing rehabilitation of patellar tendon injuries using innovative wearable technology and quantitative magnetic resonance imaging techniques

ABSTRACT My career goal is to optimize rehabilitation, improve treatment outcomes, and mitigate the debilitating long-term consequences from lower extremity tendon injuries. In this study I propose to enhance the treatment for patellar tendon injuries. The patellar tendon is a key structure for force transmission, mobility, and locomotion. The best evidence-based treatment for tendon injuries involves tendon loading via exercise; however, establishing optimal dosing remains a challenge. Clinical trials have prescribed exercises assuming external loads serve as surrogates for tendon load, however, this assumption is not entirely accurate due to commonly observed compensations at adjacent joints in patients with knee injuries. Thus, methods to directly measure tendon load are needed. Shear Wave Tensiometry (SWT) is a clinically feasible, wearable technology that can directly measure tendon load in-vivo. Neuromuscular Electrical Stimulation (NMES) during exercise is a promising approach that may improve outcomes by augmenting tendon load, yet its direct effects on tendon load have not been quantified due to lack of innovative technology to study the effects. Current methods for assessing recovery from tendon injuries are also insufficient for accurately capturing effectiveness of treatments. Tendon pathology observed at the macrostructural level does not always relate with symptoms, and improvements in symptoms tend to precede changes to tendon macrostructure. Diffusion Tensor Imaging (DTI), a magnetic resonance imaging based method to measure tendon microstructure in-vivo, offers potential to better study tendon pathophysiology and treatment response. This project aims to capture tendon adaptations at the microstructural level using DTI in response to a rehabilitation program focused on tendon loading quantified via SWT and enhanced by NMES. Two patellar tendon injuries will be studied: patellar tendinopathy and bone-patellar tendon- bone autograft harvest for anterior cruciate ligament reconstruction. Aim 1 will establish DTI methodology to quantify patellar tendon microstructure and the relationship with knee function in patients with patellar tendon injuries. Aim 2 will quantify patellar tendon loads using SWT during key rehabilitation exercises with and without NMES in patients with patellar tendon injuries and in a healthy cohort. We will rank tendon loads during exercises and compare the rankings between patients with patellar tendon injuries and healthy controls. The ability of NMES to augment tendon load will also be studied. Lastly, Aim 3 will develop and determine the preliminary efficacy of a SWT-informed rehabilitation protocol and quantify the treatment effects using DTI in patients with patellar tendinopathy. In a 12-week clinical trial, we will assess improvements in patient symptoms and function, and if DTI can capture acute microstructural changes in response to treatment. Through the K99/R00 award, I will gain the qualifications and preliminary data necessary to independently lead randomized controlled trials. This research proposal is expected to broadly impact tendon injury rehabilitation, potentially improving treatment for multiple tendons and pathologies.