Scar formation and ligament healing.

Ligaments are highly organized, dense, fibrous connective-tissue structures that provide stability to joints and participate in joint proprioception. Injuries to ligaments induce a healing response that is characterized by the formation of a scar. The scar tissue is weaker, larger and creeps more than normal ligament and is associated with an increased amount of minor collagens (types III, V and VI), decreased collagen cross-links and an increased amount of glycosaminoglycans. Studies have shown that certain surgical variables alter the healing of ligaments. Such factors include the size of gap between the healing ligament, ends, the use of motion in a stable joint and the presence of multiple ligamentous injuries. Research on ligament healing includes studies on low-load and failure-load properties, alterations in the expression of matrix molecules, cytokine modulation of healing and gene therapy as a method to alter matrix protein and cytokine production.