Massive juxta-articular defects of the distal femur reconstructed by series connected double-strut free-vascularized fibular grafts

Background: We evaluate the clinical results of reconstructing massive juxta-articular defects of the distal femur (mean, 16.4 cm) with series-connected double-strut free-vascularized fibular grafting (FVFG) and external fixator fixation. Methods: We retrospectively reviewed a consecutive series of 19 patients, who underwent FVFG transfer because of massive juxta-articular defects of distal femur. Sixteen cases had complete records and included in this study. Five patients underwent double-strut FVFG and 11 patients underwent series-connected double-strut FVFG. FVFG was performed from 2 months to 3 months after the clinical signs of the infection had subsided and erythrocyte sedimentation rates had returned to normal. Both fibulas (mean, 18.6 cm) were harvested to reconstruct the femoral defect, half-ring sulcated external fixator (Orthofix Srl, Italy), and K-wires were used to provide stabilization. Results: Five fibular grafts (15.6%) had vascular complications on flap monitoring. Fifteen of the sixteen reconstructed femurs (93.8%) united primarily. Stress fracture occurred in one patient. The mean duration to achieve union was 7.1 month (range, 4–18 months). Full weight-bearing walking was allowed 3 months after the confirmation of bone union (mean, 10 months; range, 7–22 months). The external fixator was removed 12.2 months (range, 10–16 months) postoperatively. The K-wires were removed 26.4 months (range, 23–30 months) postoperatively. There was no statistically significant difference of hypertrophic change between series-connected grafts and conventional double-strut grafts (27.18 vs. 24.43%, p = 0.186) and also between the three levels of the grafted fibula. Within the series-connected group, the difference of hypertrophic change between anterograde fibular grafts and retrograde fibular grafts was also not significant (25.24 vs. 29.12%, p = 0.178). The overall rate of knee stiffness (<90 degree) was as high as 68.75% (11 of 16 patients). Conclusions: Massive juxta-articular defects of the distal femur are difficult and uncommon injuries. The results of this study indicate that the huge femoral defect reconstructed by series-connected double-strut FVFG provide good results in achieving bone union, reducing stress fracture rate, and achieving leg length equality.