Tendon loading profiles that promote healing in Achilles tendinopathy

PROJECT SUMMARY Mid-substance Achilles tendinopathy is a painful, debilitating, and chronic tendon pathology. Rehabilitation exercises are the first treatment option for patients, but clinical studies have reported 20-60% of patients continue to experience pain and symptoms 5-years later. Even when patients experience symptom relief, only one-quarter of these patients fully recover muscle-tendon function. Current clinical guidelines recommend patients perform heel-rise exercises to eccentrically load the pathologic tendon and promote healing. However, Achilles tendon loading during daily-living often exceeds these structured rehabilitation loads, and the biomechanical properties of pathologic tendon varies amongst patients. Identifying patient subgroups based on similarities in tendon loading and biomechanics is a critical next step towards improving patient outcomes and tendon healing. Our long-term goal is to develop personalized rehabilitation protocols that maximize tendon recovery following acute and chronic Achilles tendon injuries. The overall objective of this study is to determine similarities in tendon loading and biomechanics in patients with mid-substance Achilles tendinopathy and how these similarities affect tendon healing, pain, and functional outcomes. This study leverages innovative techniques to 1) continuously monitor Achilles tendon loading during rehabilitation and daily-living and 2) quantify tendon status using ultrasound stress-imaging. Aim 1 will identify groups of patients with Achilles tendinopathy based on loading patterns and stress-imaging profiles. Aim 2 will determine if tendon healing and outcomes change over time. Aim 3 will explore the impact of sex on tendon healing and outcomes. This study will be the first to identify Achilles tendon loading profiles that are associated with tendon healing and outcomes based on patient-specific factors including tendon biomechanical properties and sex. By measuring circulating levels of sex hormones, this study will determine if specific levels of estrogen and progesterone – which can be modified using hormonal contraceptive pills – impact tendon health. Finally, with the recent shift towards telemedicine, this study will remotely monitor Achilles tendon loading, which has the potential to expand clinical care beyond patient visits to the clinic.