Functional outcomes and quality of life following free fibula flap harvest: a comparative analysis of flexor hallucis longus resection versus preservation

Background The free fibula flap (FFF) is a gold standard for maxillofacial reconstruction, yet debate persists regarding the functional impact of flexor hallucis longus (FHL) resection. This study evaluates donor-site morbidity and quality of life (QoL) following FFF reconstruction, comparing outcomes with and without FHL resection. Methods A retrospective analysis of prospectively collected data was conducted for 93 patients undergoing FFF reconstruction. Patients were stratified into FHL-harvested and non-FHL groups. Primary outcomes included QoL, AOFAS scores, hallux flexion strength, range of motion (ROM), isokinetic dynamometry, and gait analysis. Assessments were performed preoperatively and at 3- and 6-month intervals. Results The study cohort comprised 93 patients, with FHL harvested in 43 cases. The FHL group exhibited transient declines in QoL at 3 months, with partial recovery by 6 months. Both groups showed similar AOFAS score trajectories, with temporary declines at 3 months and near-complete recovery by 6 months. Hallux flexion strength decreased comparably in both groups at 3 months (FHL: −38%; non-FHL: −34%), with residual 18–20% deficits at 6 months. Isokinetic testing revealed transient plantar flexion weakness in the FHL group at higher velocities (90°/s: 54.2 ± 7.0 Nm vs. 58.6 ± 7.5 Nm pre-op, p=0.008), resolving by 6 months. Gait analysis demonstrated initial impairments in stride length and ankle ROM in the FHL group, normalizing by 6 months. Conclusion FHL resection during FFF harvest leads to transient functional and QoL impairments, but most deficits resolve within 6 months. Preservation is advisable when feasible, though FHL harvest remains safe for cases requiring additional soft tissue.