Predictors of Amputation after Lower Extremity Salvage: Findings from a 30-year Cohort

Background Though limb salvage aims to restore form and function in the setting of severe trauma, some patients ultimately require secondary amputation, defined as amputation performed after attempted reconstruction. This study aims to identify risk factors for secondary amputation among patients undergoing salvage and to characterize and compare risk factors for early (<90 days) versus late (>90 days) secondary amputation. Methods A retrospective review of patients undergoing lower extremity salvage over 29 years (1994-2023) at a Level-I trauma center was performed. Demographics, injury characteristics, reconstructive details, complications, and outcomes were analyzed. Univariate and multivariable logistic regression identified predictors of secondary amputation and factors associated with early versus late amputation. Results Among 272 patients (average age 42 years; 77.9% male), 307 flap reconstructions were performed. Secondary amputation occurred in 32 (11.8%) patients. Patients with free flap reconstruction were more likely to undergo secondary amputation (p=0.003). Multivariable analysis demonstrated that postoperative soft tissue complications, particularly surrounding tissue (non-flap) necrosis, were significantly associated with increased risk of amputation (p<0.001). Reconstructive timing was also significant, as reconstruction performed 11-14 days from injury (p=0.001) or from first debridement (p=0.003) was associated with increased amputation risk, whereas reconstruction within 4-7 days from first debridement was protective (p=0.044). Among patients who underwent amputation, 40.6% were early and 59.4% late. All patients undergoing early amputation had associated soft tissue complications (p=0.025), while late amputation was associated with bony complications (p=0.033) and initial evaluation at an outside hospital (p = 0.010). Conclusion Pursuing limb salvage versus amputation for patients with limb-threatening trauma remains a complex surgical decision. Surrounding tissue necrosis is strongly associated with early amputation, while bony complications are associated with late amputation. These findings emphasize the importance of vigilant soft tissue assessment and monitoring, careful reconstructive timing, and coordinated orthoplastic care to optimize limb salvage durability.