Stress Analysis of the Vascularized Fibular Bone Transplantation in Large Tibia Defect Reconstruction: A Finite Element Study

Abstract

ABSTERMicrosurgical vascularized bone graft has been successfully used to treat large tibiat defects, The shape, size and length of the fibula make it a popular donor site for most tibia defects. The goal of this study is to numerically analyze the stress distribution in the transferred fibula and to evaluate the nature of the placement of the fibulur graft and its relations to failure. A finite element analysis was conducted lo investigate the stress distribution and to predict the stress fracture positions in transferred bones. The calculated results matched well with clinical observations. The simulation suggests that those grafts having a lower site transfer exhibit a higher level of stress distribution. The finite element model also suggests that the stress level of an obliquely placed graft is higher than thai of a vertically placed graft, especially at the distal tibia-fibula junction. A longer period of protection is therefore recommended for the treatment of a lower site transfer or an obliquely placed grafted bone to avoid bone stress fracture.Btomed Eng Appl Basis Comm, 2001 (October); 13: 218-225.

Case Report: Large bone defect reconstruction in lower extremities with ipsilateral transposition fibular graft with combined inlay and onlay technique using plate and screw fixation (fibula pro tibia technique)

“…2,3 The fibula is a suitable graft material because of its long, straight cortical bone that can bridge most defects, good structural strength, osteogenic potential, does not cause distant donor site morbidity and, unlike allografts, it has no immunogenicity, thus making the fibula a popular donor site for long bone defects. 1,5,10 The fibula also bears just 6-15% of the weight transmitted via the leg, and it is considered expendable. 4 The size of the fibular graft and its straight configuration allows it to fit into the femur or tibia medullary canal, allowing restoration of significant defects up to 26 cm in length.…”

“…In addition, unlike an allograft, it has no immunogenicity. 1,4,5,10 The vascularized bone graft maintains its mass and architecture better than an avascular fibular graft, is biomechanically stronger and has better healing potential and hypertrophy. Furthermore, in scarred and avascular recipient locations, the vascularized bone transplant provides a significant source of vascularity.…”

“…Creeping substitution process characterized by graft necrosis, resorption, and new bone growth in avascular transplants. 5,10,11 In a study by Föhn et al, the ipsilateral fibula was used as a bone graft and positioned into the proximal and distal medullary canal of the fractured site with its peroneal and periosteal vascularization. 9 The technique used in this case was the same, but we performed an additional onlay technique using an ipsilateral avascular fibular graft to provide more mechanical strength to the injury site.…”

“…However, if the external mechanical loading is greater than the bone's strength, a stress fracture will occur. 10 We planned gradual weight bearing with serial radiography follow-up to avoid stress fractures until the bone graft had hypertrophied sufficiently before total weight-bearing.…”