Dolph Houben

68 CHAPTER 3 Free vascularized bone flaps necessitate microvascular repair of the nutrient vessels, which are associated with a low ( < 5%) risk of thrombosis of the micro anastomosis [37] . Failure to detect and revise early thrombosis of the anastomosis results in an avascular reconstruction. Non- vascularized reconstructions are submissive to creeping substitution. Thus, result is impaired strength and stress fractures over time [36] . Although the incidence of these complications is low, these results would be similar to reconstructions with a massive allograft alone. This systematic review is limited by the level of evidence provided in the literature. All included articles had a level IV evidence except for one study with level III evidence [25] . Because of the difference in data reporting in each study, interpretation bias might have occurred in this review. To minimalize this interpretation bias we used a standardized data extraction form. To compare the results of the included studies, subgroups were made for different outcomes. The main limitation of this study is the lack of comparative studies in literature. The results of this systematic review show a wide variety of overall complication rates (5.9- 85.7%). This is probably due to the limitation of taking the overall complication rate of each study, but it indicates the complexity of this type of reconstruction. Various factors contribute to the incidence of complications after reconstruction with a massive allograft combined with vascularized bone autograft. The most important factor we found is the use of perioperative chemotherapy or radiation [7, 13, 14, 16, 22, 23, 25] impairing the biological activity. According to the complication rates, re-intervention rates varied from10-91.7 percent. Re-intervention often involved secondary bone grafting to achieve final union. Although this reconstruction method is associated with high complication and re-intervention rates our meta-analysis showed high primary union rates in 86.5% of the cases with good functional outcome (mean MSTS: 26.3) after this complex type of reconstruction. The combination of a massive allograft with a vascularized fibula provides a single step reconstruction with good long-term outcomes in large segmental defects of various natures. This technique should especially be considered for treatment of large segmental defects in the lower extremity due to resection of primary bone tumors. Complications are manageable, albeit complication rates are high.