Long-term Evaluation of Free Fibular Flap in Extremity Bony Reconstruction.

Abstract

Background: Free fibular flaps (FFF) and pedicled fibular grafts (PFG) are established techniques for reconstructing pediatric long bone defects. While the FFF provides versatility through microvascular transfer, PFGs avoid anastomosis but are limited by anatomic constraints. Clinical questions remain regarding optimal fixation strategies, donor-site morbidity, and graft outcomes in children.

Methods: This retrospective cohort study analyzed 22 pediatric patients undergoing FFF or PFG between 1994 and 2025. Outcomes included time to radiographic union, time to weight bearing, fibular regeneration, and donor-site complications. Subgroup analyses compared external fixation use, periosteal sleeve preservation, and graft type/location.

Results: The average time to radiographic union was 41 weeks. External fixation was associated with shorter radiographic union time (30.1 vs. 86.4 wk) and earlier full weight bearing on the graft-receiving limb (52.0 vs. 127.2 d), though these findings should be interpreted as exploratory given the limited sample size and inconsistent significance across statistical tests. Younger patient age correlated with faster union (r = 0.60, P = 0.004). Preservation of a periosteal sleeve at the donor site significantly promoted fibular regeneration (P = 0.0004) and may hasten donor limb recovery. Ankle valgus deformity was associated with shorter residual distal fibula length (mean 5.6 cm, P = 0.0498). All grafts showed remodeling over time. Tibial graft location and use of PFG were significantly associated with need for refixation (P = 0.0001 and P = 0.0002, respectively).

Conclusion: Pediatric FFF reconstruction demonstrates high union and remodeling rates with favorable functional outcomes. External fixation was found to be weakly associated with acceleration of union and weight bearing, while periosteal sleeve preservation supports fibular regeneration and potentially expedites return to weight bearing on the donor limb. PFGs may be effective in select tibial cases but showed higher reoperation rates. Preserving an adequate distal fibula segment may mitigate ankle valgus. These findings support tailored fixation strategies and highlight the importance of surgical planning to optimize outcomes and minimize donor-site morbidity in pediatric patients.

Level of evidence: Level III-therapeutic study.