Dolph Houben

102 CHAPTER 5 Results Surgical outcome Our study used two experimental groups to evaluate the effect of the implantation of an autogenous AV-bundle on recipient-derived neo-angiogenesis, graft viability, and bone remodeling. The VCA studies were designed with a cohort of Yucatan swine (n=14) divided into two treatment groups (n=7 each; Group 1: tibial VCA + autogenous angiogenesis; Group 2: tibia VCA no autogenous angiogenesis control. All animals were able to ambulate with partial weight bearing immediately post-operatively, with full weight bearing by the fourth postoperative day in both groups. One abscess occurred at six weeks with a deep infection as a result. Six weeks after transplantation, another animal developed uncontrollable seizures. Extensive treatment was without success, requiring its sacrifice. Due to these complications, the two animals were excluded from this study for analyses. Thus, a final cohort of twelve pigs remained for analysis (6 in each group). No fractures were observed in these twelve animals and they all went into complete union of the proximal host-allotransplant interface, while only three pigs exhibited an incomplete union of the distal interface. Neo-angiogenesis To evaluate neo-angiogenesis within the allotransplant we performed a micro-angiography of the allotransplant to visualize the vascular pattern within the allograft. The micro-angiography showed that all AV-bundles (N=6) in group 1 were patent at 20 weeks. These implanted AV- bundles sprouted numerous neoangiogenic vessels within the medullary space and endosteal surface of the allotransplanted tibial segment. (Fig. 2A+B). The control group (group 2) had no significant medullary vasculature. In group 2, the source of bone blood supply came from the external cortical surface, consequent to contact the adjacent soft tissues (Fig. 2 C+D). The medullary vessel volume and calculated capillary density in the medullary proportion of the allotransplant were statistically significant higher in Group 1 than Group 2 (p=0.04) (Table 2). No significant difference could be found for the total and cortical proportions in vessel volume and capillary density.