Models for the study of tendinopathy.

Tendinopathy refers to the clinical presentation of activity-related pain, focal tendon tenderness, and intratendinous imaging changes. The underlying pathology was once thought to be due to inflammation ('tendinitis'), but is now considered to predominantly result from degeneration ('tendinosis'). While some progress has been made in understanding tendinosis, the condition remains poorly understood and a need exists for suitable exploratory preclinical models. It is unlikely that one suitable model exists because of the complexity of the underlying pathology and myriad of possible causes. This paper provides an overview of current models utilized in tendinopathy research. It progresses hierarchically from in vitro and ex vivo models to in vivo models. For each model, rationale for use, pertinent findings, and advantages and disadvantages are discussed. By improving on these models, new methods for the prevention and treatment of tendinopathy may be explored with the ultimate outcome being a reduction in the occurrence and effects of the condition in humans.