Tendon regeneration in human and equine athletes: Ubi Sumus-Quo Vadimus (where are we and where are we going to)?

Tendon injuries are one of the most common orthopaedic problems in both human and equine athletes. When a damaged tendon heals naturally, it loses a substantial part of the original strength and elasticity. Therefore, tendons recover structurally (reparation) but not functionally (regeneration) after conservative medical or surgical treatment. Since the structure and matrix composition of human and equine tendons share many similarities, the nature of tendon injuries are also strongly comparable in both species. Therefore, the evaluation of regenerative therapies in horses may have applications for future human medicine and vice versa. The current review focuses briefly on the physiology of human and equine tendon in order to better comprehend the modus operandi of this structure under pathophysiological circumstances. In addition, the reparative effects of conservative medical and surgical interventions are discussed concisely, and an extensive overview is given on the regenerative therapies that are currently being explored. For the latter, the results of equine clinical studies might prove invaluable for gaining additional insights into the treatment of human tendinopathies, since not all of these novel regenerative therapies have been evaluated in humans yet.