How medical engineering has changed our understanding of chronic wounds and future prospects.

Chronic wounds which fail to progress to healing are currently considered among the most important, unsolved and expensive medical burdens, on the same scale of healthcare costs as all obesity-related problems taken together. Pressure ulcers (PUs) and diabetic foot ulcers (DFUs) make the most significant portion of these hard-to-heal wounds. Our research in the last twenty years has explained why quantitative, absolute and generic injury thresholds to predict when PUs or DFUs may occur will forever remain intangible, despite the vast efforts and resources that have been invested in allegedly discovering such injury thresholds. This perspective article explains the specific reasons for this, yet, it also describes the routes for constructive future medical engineering work which will likely lead to better prevention and treatment of PUs and DFUs, even if currently there are no simple or straight-forward injury thresholds to predict when a person may suffer a chronic wound. The role of mechanobiology, as a relatively new medical engineering discipline, is being depicted, in the context of basic and applied chronic wound research. Physical and biochemical biomarkers for early detection and for targeting prevention are also discussed, given the availability of mechanobiological approaches and methodologies to discover or test feasibility of such biomarkers towards clinical use. Finally, some inherent complexities in the prevention and treatment of PUs and DFUs are elucidated, particularly that: (i) the susceptibility to chronic wounds depend on integrated body system functions which are extremely difficult to predict in individuals, especially in seriously ill patients, and (ii) a continuum exists between prevention and treatment of wounds, and hence, in many cases, clinicians are required to treat an existing wound and protect adjacent tissues from deteriorating at the same time. This paper is an overview of our contemporary research concepts and latest published aetiological discoveries related to chronic wounds. Interested readers are encouraged to further study our cited literature for comprehensive analyses of the multiple specific topics that are briefly described here.