Long-term behaviour of the free vascularised fibula following reconstruction of large bony defects.

Thirty-two free vascularised fibula grafts performed at our unit have been assessed retrospectively with respect to success, bony union and percentage graft hypertrophy. Between 1981 and 1998, there were 21 males and 11 females (aged 8-61 years) with follow-up of 5 months to 14.6 years. The mean bony defect bridged was 12.0 cm (standard deviation 4.8; range 5.0-21.0 cm). Bony union and hypertrophy were assessed radiographically. Time to bony union was compared using the log-rank, Wilcoxon or likelihood ratio tests. Kaplan-Meier survival curves were constructed. Hypertrophy was compared with Wilcoxon's rank sum test.Three flaps failed. Seventy-four percent of patients healed primarily at a median time of 4.75 months; five patients required further surgery to heal by 18 months (interquartile range 14-20 months). Complication rate and donor site morbidity were low. The stress fracture rate was 21%. Ninety percent of patients regained a functional limb by 12 months.Hypertrophy was measured in 22 patients and ranged from 0 to 316% (median 71%; interquartile range 10-145%). Median hypertrophy in the lower limb was 76.5% (interquartile range 26.5-165%) compared to 33.5% in the upper limb (0-88%); p=0.16. Median hypertrophy in trauma cases was 80% (interquartile range 10-167%) compared to 70% in tumour cases (33-105%); p=0.62.Our findings confirm that the fibula responds physiologically to biomechanical loading. Our results compare well with other series and alternative reconstructive modalities. We conclude that the free fibula flap can provide excellent results in the salvage of limbs with large bony defects.