Background
Soft tissue coverage of Gustilo-Anderson 3B and 3C tibia fractures often requires microsurgical free tissue transfer to achieve definitive limb salvage. Even after successful reconstruction, deep infection remains a primary driver of secondary amputation. Susceptibility to infection is multifactorial, stemming from biofilm formation on internal hardware, post-traumatic dead space, and reduced fracture site perfusion1,2. This study evaluates determinants influencing infection rates and free flap outcomes within a sample of New Zealand patients.
Methods
Records of 57 open tibia fractures requiring free flap coverage at Middlemore Hospital (2014–2024) were retrospectively reviewed. A generalized multivariate linear model was used to determine the impact of ischaemic time, total number of acute operations, and Injury Severity Score (ISS) on outcomes. Primary endpoints included early flap failure, microbial infection, limb salvage and deep infection, with age at injury included as a covariate in the analysis.
Results
Patients with partial or complete early flap failure had ISS scores 10.67% higher than those without failure (p<0.04). Early flap failure and deep infection were associated with 2.0 and 1.49 more acute operations, respectively (p<0.04). Interestingly, injury severity and total acute operation number did not significantly contribute to late deep infection. Ischaemic time did not correlate with flap failure. Limb salvage and late deep infection were not significantly affected by the measured parameters in this cohort.
Conclusion
Strong correlations exist between early flap failure, infection, injury severity, and surgical burden. These findings support the "Fix and Flap" philosophy of minimizing acute operations and optimizing early coverage to improve outcomes in high-energy tibia trauma.3
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