Objectives. Inflammation of the
Tendon is a bradytrophic and hypovascular tissue, hence, healing remains a major challenge. The molecular key events involved in successful repair have to be unravelled to develop novel strategies that reduce the risk of unfavourable outcomes such as non-healing, adhesion formation, and scarring. This review will consider the diverse pathophysiological features of tendon-derived cells that lead to failed healing, including misrouted differentiation (e.g. de- or transdifferentiation) and premature cell senescence, as well as the loss of functional progenitors. Many of these features can be attributed to disturbed cell-extracellular matrix (ECM) or unbalanced soluble mediators involving not only resident tendon cells, but also the cross-talk with immigrating immune cell populations. Unrestrained post-traumatic inflammation could hinder successful healing. Pro-angiogenic mediators trigger hypervascularization and lead to persistence of an immature repair tissue, which does not provide sufficient mechano-competence. Tendon repair tissue needs to achieve an ECM composition, structure, strength, and stiffness that resembles the undamaged highly hierarchically ordered tendon ECM. Adequate mechano-sensation and -transduction by tendon cells orchestrate ECM synthesis, stabilization by cross-linking, and remodelling as a prerequisite for the adaptation to the increased mechanical challenges during healing. Lastly, this review will discuss, from the cell biological point of view, possible optimization strategies for augmenting Achilles tendon (AT) healing outcomes, including adapted mechanostimulation and novel approaches by restraining neoangiogenesis, modifying stem cell niche parameters, tissue engineering, the modulation of the inflammatory cells, and the application of stimulatory factors. Cite this article:
The June 2012 Foot &
Ankle Roundup360 looks at: the Achilles tendon Total Rupture Score (ATRS); endoscopic treatment of Haglund’s syndrome; whether it is worth removing metalwork; hyaluronic acid injection; thromboembolic events after fracture fixation in the ankle; whether surgeons are as good as CT scans for OCD of the talus; proximal fractures of the fifth metatarsal; nerve blocks for hallux valgus surgery; chronic osteomyelitis in the non-diabetic patient; Charcot arthropathy.
The August 2012 Foot &
Ankle Roundup360 looks at: calcaneocuboid distraction arthrodesis with allograft for acquired flatfoot; direct repair of the plantar plate; thromboembolism after fixation of the fractured ankle; weight loss after ankle surgery; Haglund’s syndrome and three-portal endoscopic surgery; Keller’s procedure; arthroscopy of the first MTPJ; and Doppler spectra in Charcot arthropathy.