Imaging of Vascularized Fibula Autograft Placed Inside a Massive Allograft in Reconstruction of Lower Limb Bone Tumors

Abstract

Bone allografts and vascularized fibula autografts were combined (the fibula inside the massive allograft) for skeletal reconstruction in a homogeneous group of patients. To verify the biologic behavior of the grafts, we followed the series using conventional radiography and CT analysis. Twenty-four patients with bone tumors had intercalary segments of tibia or femur reconstructed and were followed up for 36-120 months. Sequential radiographs and CT scans were analyzed. Three types of behavior were observed. In 13 patients, the allograft maintained its architecture without fracture, although a regular enlargement of the inlaid fibula led to progressive integration with the allograft. A dense line on allograft endosteum was the first sign of bone bridges heralding fusion of the two grafts. In eight patients, fracture or nonunion of the allograft occurred, and the autograft reacted with rapid appearance of dense hypertrophy that again induced bridges to the allograft. In three patients, no changes in autograft size and density were followed by fracture with no callus formation. This behavior was interpreted as unsuccessful vascularization of the autograft. Sequential radiography and CT analysis enabled us to understand the changes in a combined graft offering an original way to revascularize bone allografts.