Tendon Pathophysiology: Current Knowledge and Future Clinical Therapies

Key Points:

• Tendons are considered to be a specialized form of fascia, the connective tissue system that permeates the entire body and forms a body-wide tensional force transmission system
• Fascia is composed predominantly of collagen I, which is a major marker of effective repair after injury
• Tendon repair and remodeling can take as long as 2 years or more.
• Means to promote more rapid and complete tendon healing are under active investigation. These include use of tendon-derived stem cells, fat- or bone marrow-derived mesenchymal stem cells, platelet-rich plasma, autologous conditioned serum and biological scaffolds.

Fascia, defined as the ‘soft tissue component of the connective tissue system that permeates the body’ is a network of connective tissue that is part of a body-wide tensional force transmission system. Fascia plays a key role in musculoskeletal dynamics: its ability to spontaneously adapt and adjust to strain or stretch makes it a critical contributor to stability and mobility.1 In fact, without fascia, muscles and their connecting tendons would be completely unable to support the body or effect movement.

In addition to local dense connective tissue components, such as tendons and ligaments, fascia forms planar tissue sheets surrounding various tissues including the muscle (endomysium, perimysium, and epimysium) as well as joint capsules and the capsules around viscera. The fundamental structure of fascia consists of fibroblasts and collagen fibers arranged in parallel in an amorphous matrix of hydrated proteoglycans.  [...]