Connective Tissue Healing and Classification of Ligament and Tendon Pathology
Tendons and ligaments are examples of organized connective tissue that share many common features, including their attachment to bone, their response to immobilization, their reaction to slowly increased stress over time, and their response to trauma and the subsequent healing events. A logical approach to rehabilitation of tendon and ligament injuries demands knowledge of the behavior of connective tissue at the microscopic and biochemical levels. A useful clinical classification of these injuries is presented, as is a discussion of the connective tissue responses to trauma and their implications for treatment planning and progression.
TENDINITIS AND TENDON RUPTURE
Inflammatory conditions of the tendons may be acute or chronic. The pathologic reaction is located mainly in the tendon sheath, with tenosynovitis, or paratendinitis.
Chronis inflammation may precipitate varying degrees of degenerative change in the tendon itself, referred to as tendinosis. The latter may be associated with structural weakening and predispose to partial or complete tendon rupture. Rupture can also occur when sufficient force is applied to normal tendons.
A normal tendon is characterized by enormous tensile strength. The crimped, ultrastructural makeup of a tendon means that initial stresses are accommodated by straightening out the crimped arrangements of the collagen fibers. Greater loads stress the fibers themselves. Most day-to-day activity and even stressful sporting maneuvers are accommodated in the toe region and early in the linearphase of the stress strain curve for tendon. The linear phase represents ligamentous elasticity, and deformation is reversible. At the high ends of functional loading, plastic deformation and even microfailure may occur.