Outcomes of Lower Limb Free Flap Reconstruction in a UK Major Trauma Centre: Acute Trauma, Delayed Breakdown, and Late Elective Reconstruction for Infected Metalwork.

Background Free flap reconstruction is integral to the management of complex lower limb trauma, yet flap failure and return to theatre remain clinically significant challenges. Outcomes may vary according to injury timing and context. Methods A retrospective cohort study was conducted at a UK major trauma centre, including patients who underwent lower limb free flap reconstruction over a five-year period. Patients were categorised into three predefined groups: acute trauma reconstruction, closed fractures with delayed soft-tissue breakdown, and late elective reconstruction for infected metalwork. The primary outcome for acute trauma was any flap loss. A composite reconstruction outcome was used for the infected metalwork cohort. Descriptive and univariable statistical analyses were performed. Results Seventy patients underwent acute lower limb free flap reconstruction. Any flap loss occurred in five cases (7.1%), including four total and one partial flap loss. Return to theatre occurred in 31.4% of cases, with all flap losses occurring in patients requiring re-exploration. No flap losses were observed in patients with initially closed fractures who later developed soft-tissue breakdown (0/10). Nineteen patients underwent late elective free flap reconstruction for infected metalwork; partial or total flap loss occurred in 31.6%, and 57.9% achieved a satisfactory reconstruction using a predefined composite outcome. Conclusions Lower limb free flap reconstruction performed within a UK major trauma centre achieves flap survival rates comparable to published benchmarks despite managing complex injuries. Distinct biological contexts, including delayed breakdown and chronic infection, demonstrate differing outcome profiles, highlighting the importance of stratified analysis when evaluating reconstructive success.