Comparing Fibula Flap Insetting Techniques for Pediatric Oncologic Extremity Reconstruction

Background: Extremity reconstruction in skeletally immature patients presents unique challenges in terms of operative technique, bone healing, and limb function. A variety of insetting techniques have been described, with no clearly superior option. The authors hypothesized that vascularized fibula flaps placed in the intramedullary space are associated with shorter union times and better functionality compared with onlay flaps. Methods: In a cohort study, the authors retrospectively reviewed the medical records of all pediatric patients who underwent fibula flap extremity reconstruction at a single center from 2001 through 2018. Comorbidities, complications, and outcomes were analyzed. Complete fibula union was based on radiographic evidence of significant cortical bridging. Results: Thirty-three patients (mean age, 13.6 years; range, 2 to 18 years) underwent pedicled (n = 7) or free (n = 26) fibula flap reconstructions in 12 upper extremities and 21 lower extremities. Median follow-up was 69.5 months (interquartile range, 16.3 to 114.6 months). Onlay and intramedullary fibula position compared with intercalary placement (median, 13.5 and 14.6 months versus 3.4 months; P = 0.002) were associated with longer time to complete bone union. Complications including allograft fracture (P = 0.02) and hardware removal (P = 0.018) were also associated with longer time to complete union and eventual conversion to megaprosthesis (P = 0.02, P = 0.038). Thirty-two patients (97%) achieved full union and a functional reconstruction. Conclusions: Fibula flap reconstruction is safe and effective for pediatric long-bone reconstruction. Longer fibula union times were associated with onlay and intramedullary fibula placement, allograft fracture, and hardware removal. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.