Temporal Changes in Cellular Repopulation and Collagen Fibril Remodeling and Regeneration After Allograft Anterior Cruciate Ligament Reconstruction: An Experimental Study Using Kusabira-Orange Transgenic Pigs.

Background:Distinguishing recipient cells from donor ligament cells is difficult in the early graft-healing phase after anterior cruciate ligament (ACL) reconstruction. The ability to track the distribution and differentiation of recipient cells using genetically engineered transgenic (Tg) animals would have significant clinical and research effects on graft healing after ACL reconstruction.Hypothesis:Kusabira-Orange Tg pigs may allow the tracking of recipient cells infiltrating the graft after ACL reconstruction. The repopulation of recipient cells within the graft would be apparent even in the early graft-healing phase when necrotic donor cells are still present.Study Design:Descriptive laboratory study.Methods:In 17 genetically engineered Tg pigs, which carried the red fluorescent protein Kusabira-Orange, ACL reconstruction was performed on the right knee using a digital flexor tendon harvested from wild-type pigs. Tissue samples harvested at different time points were subjected to histological, immuno...