BIOLOGIC REMODELING AFTER ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION USING A COLLAGEN MATRIX DERIVED FROM DEMINERALIZED BONE - AN EXPERIMENTAL-STUDY IN THE GOAT MODEL

A matrix of demineralized cortical bone was used to reconstruct the an terior cruciate ligament in the goat model, This graft underwent consi derable site-specific remodeling and transformation from a Haversian s ystem at time zero into a ligament-like structure at 1 year. This tran sformation included new bone formation filling the osseous tunnels and replacing the demineralized matrix, development of a ligament-like tr ansition zone within the graft, and ligamentous collagen orientation w ith crimp in the intraarticular portion of the graft. One year after s urgery, the mean anterior-posterior translation in the reconstructed s tifle joints at 30 N of tibial loading was 2.1 +/- 0.4 mm (+/-SEM). Th e mean ultimate force to failure for the reconstructed ligament at 1 y ear was 474 +/- 146 N compared with the time-zero (initial) strength o f the matrix of 73 +/- 9 N. The cellular repopulation of the graft had no associated inflammatory cells. The potential clinical significance of these findings includes 1) replacement of a collagen matrix with b one within the osseous tunnels, 2) establishment of a more physiologic fibrocartilage transition at the graft insertion site, 3) the time-ze ro structural properties of a collagen matrix increasing to more desir ed values with biologic remodeling, and 4) a sterile biologic allograf t with essentially no long-term inflammatory response.