Computerized quantification of collagen alignment in nonimmobilized and immobilized healing ligaments

A ligament heals by production and remodeling of collagen in scar tissue. Remodeling includes realignment of collagen fibrils. A computer technique has been developed to quantitatively analyze collagen alignment. With this method, the remodeling of collagen in immobilized midsubstance injuries of the rabbit knee medial collateral ligament were compared with that in nonimmobilized rabbits. The nonimmobilized scar at 3 and 6 weeks had significantly greater randomness and dispersion of collagen fibrils than normal ligament tissue (p<0.05). However, at 14 weeks of nonimmobilization and at all intervals of immobilization, the collagen fibril alignment of the healing scar was not significantly different than normal ligament. These results suggest that short-term immobilization allows earlier collagen realignment in rabbit medial collateral ligament scar.<>