Extrinsic risk factors for tendinopathy: bridging the basic and clinical research divide.

PURPOSE: Tendon injuries frequently affect the Achilles, rotator cuff, and the tendons of the wrist extensors originating at the lateral epicondyle. Until recently, terms for tendon degeneration, disease, and injuries were debated between the basic research and clinical communities, creating barriers to advances in knowledge. Aside from acute traumatic rupture in healthy tendon, in the current 'omic age, most tendon disease, including ruptures in chronic disease, exists along a tendinopathy spectrum. While intrinsic factors such as sex, genetics, and aging are unmodifiable, extrinsic factors impact tendon health, and have been extensively evaluated in both basic and clinical research. However, these fields do not always ask aligned research questions, leading to unanticipated gaps in understanding the impact of extrinsic factors on tendon health. The aim of this study was to provide a detailed and cohesive review of these gaps between current clinical and basic science research.

METHODS: We analyzed extrinsic risk factors for tendinopathy by searching PubMed utilizing search terms related to tendinopathy, various anatomic sites, and various extrinsic risk factors. Reviewed literature was separated into basic science and clinical research. Current knowledge was summarized and gaps identified between fields.

RESULTS: Several extrinsic risk factors are directly connected to the onset of tendinopathy whether through upregulation of systemic inflammatory mediators or direct effects on tendon structure and function.

CONCLUSIONS: There is much work to be done to explain the mechanisms of action highlighted by clinical data, particularly when considering the complexity of disease and associated comorbidity.