In Vivo Transplantation of Neonatal Ovine Neocartilage Allografts

Following transplantation of ovine neocartilage allografts, 26 sheep were divided into groups according to the following weight-bearing schedule : 8-week nonweight bearing (8NWB, n=14), and 8-week nonweight bearing+ 4-week weight bearing (8NWB+ 4WB, n=12). In addition, 7 and 6 sheep, respectively, in the 8NWB and8NWB+ 4WB groups received tTG treatment after allograft transplantation, whereas the remaining 13 sheep in these groups did not receive tTG. Finally, 8 sheep served as sham-operated controls without allograft transplantation. After euthanasia, stifle joints were harvested for the analysis of gross appearance, chondrocyte viability, histology, and biomechanical testing.graft survival and union with host tissue in both 8NWB and 8NWB+ 4WB groups between the tTG treated and non-tTG treated animals. Analysis of his-tological scores demonstrated no significant difference between tTG and non-tTG treatments in both 8NWB and 8NWB+ 4WB groups. Confocal laser microscopic analysis of the explanted defects revealed 70%-100% cell viability in all treatmentgroups.This study shows that allogeneic chondrocytes harvested from neonatal donors provide sufficient metabolic activity to affect repair. Use of tTG to augment resorbable suture fixation of neocartilage grafts providedno advantage over suture alone in this pilot study.