Patient subgroups of Achilles tendinopathy: clinical implications to inform precision treatment strategies
Date
2022
Authors
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Publisher
University of Delaware
Abstract
Achilles tendinopathy is a pervasive painful condition that impacts the ability to be physically active, occupational productivity, and quality of life. Achilles tendinopathy occurs equally in men and women, with highest prevalence occurring in middle-aged adults. The lifetime incidence is estimated to be 50% among runners and 5.9% in the general population. Achilles tendinopathy has historically been considered a sports injury, however 65% of cases in the general population have no association with sports participation. The patient population is diverse, ranging from elite athletes to older adults with metabolic disease. Although the hallmark symptoms of pain with loading are shared by all, the general health impairments and alterations in tendon structure vary widely among those afflicted. These impairments can be described on a spectrum summarized by the tendon health model. The domains of the tendon health model include symptoms, lower extremity function, tendon structure and mechanical properties, psychological factors, and patient-related factors. ☐ Exercise therapy is the first line of care to address deficits in tendon health, however between 20-40% of patients experience continued symptoms at 5-year follow-up. Despite previous studies addressing inadequacies of the current one-size-fits-all treatment approach, no study has prospectively characterized who are the patients that respond unfavorably to the standard of care. Comprehensive evaluation of each domain of tendon health may be required to identify specific barriers to recovery for patients when with exercise therapy alone. After recognizing these barriers, precision treatment approaches can be developed to address these individual deficits in tendon health to ensure complete and lasting recovery for all. ☐ This dissertation work leveraged the tendon health model to identify patient subgroups with Achilles tendinopathy and revealed implications of subgroup membership for recovery. In the first aim, three latent subgroups among patients with Achilles tendinopathy (insertional and midportion) in the general population were identified with distinct characteristics and clinical deficits. In the second aim, the reproducibility of the subgroups was confirmed in a cohort with only midportion Achilles tendinopathy and differences were observed in recovery trajectories of symptoms, function, tendon structure, and psychosocial factors following 24 weeks of exercise therapy and activity modification. The adolescent population is another group contributing to the heterogeneity of the patient population, but is often excluded from Achilles tendinopathy studies. Therefore, the final aim of this dissertation determined that adolescents with heel pain can present with isolated Achilles tendon pain, heel pain related to calcaneal apophysitis, or concurrent injury. Additionally, Aim 3 determined that treating adolescents with heel pain with exercise therapy and activity modification for 12 weeks is appropriate and feasible for conducting a larger clinical trial to evaluate treatment effectiveness. Collectively, the findings of this dissertation work could drive a shift in treatment from a one-size-fits-all approach to precision treatment strategies for patients with Achilles tendinopathy and transform clinical perceptions and management strategies for adolescents with heel pain.
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Keywords
Achilles, Exercise, Mixture modeling, Tendon