Patellar tendinopathy: optimizing outcomes of exercise therapy using a comprehensive approach to tendon health
Date
2020
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Publisher
University of Delaware
Abstract
Patellar tendinopathy is chronic, painful, overuse injury to the patellar tendon. It is rampant among jumping athletes, with 11.8-14.4% of recreational and 32-45% of elite volleyball and basketball players reporting symptoms. These athletes also suffer from impaired function, decreased sports performance, and lost playing time. Exercise therapy is the treatment with the highest level of evidence.This treatment consists of controlled patellar tendon loading, which results in tendon remodeling and ultimately, a reduction of symptoms. Although exercise therapy has proven effectiveness, patients only average 52-79% of full recovery following 12 weeks of treatment, with minimal further improvements at one year. Up to one half of these patients will experience reinjury and greater than 50% of those will retire from their chosen sport due to recurrent symptoms. ☐ A singular focus on pain resolution may be to blame for these suboptimal outcomes and high rates of reoccurrence, as resolution of pain does not ensure full recovery of tendon health. In addition to pain, patellar tendinopathy is accompanied by alterations in tendon morphology and mechanical properties, decreased lower extremity function, and impaired quadriceps muscle performance. Furthermore, there may be underlying risk factors that contributed to the initial development of the injury. These additional impairments and underlying risk factors may not be addressed by patellar tendon loading alone and persist after pain has resolved, acting as a barrier to complete recovery and leaving athletes vulnerable to reinjury. Therefore, the goal of this dissertation work is to optimize outcomes of exercise therapy for patellar tendinopathy using a comprehensive approach to tendon health. This approach broadens the current pain-focused approach to include other domains of tendon health impacted by the injury. ☐ In the first aim, modifiable risk factors and factors associated with patellar tendinopathy were investigated in a systematic review and meta-analysis. Identification of modifiable risk factors may lead to new treatment avenues and enhance the effectiveness of treatment and prevention programs. In the second aim, the reliability and stability of continuous shear wave elastography (cSWE) was established for measuring mechanical properties of the patellar tendon. cSWE is painless, non-invasive form of ultrasound imaging with the ability to measure mechanical properties in-vivo. These properties may be a more responsive measure of tendon health than previously utilized metrics and allow clinicians to better tailor loading to individual patients. In the third aim, relationships between tendon structure (morphology and mechanical properties) and other components of tendon health were investigated. An improved understanding of the role of tendon structure in tendon health may lead to more targeted treatments, which aim to resolve impairments in other domains by addressing the contribution of tendon structure. Finally, the fourth aim examined the feasibility of a randomized clinical trial utilizing pain-guided activity modification during exercises therapy for patellar tendinopathy. Greater activity levels are a risk factor for patellar tendinopathy but clinicians lack guidance on appropriate recommendations for modifying activity during treatment. This work may lead to improved activity modification recommendations that optimize outcomes while maintaining the physical and mental health of athletes.
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Keywords
Activity Modification, Elastography, Jumper's Knee, Rehabilitation, Tendinitis, Tissue Mechanics