Background: In patients with non-healing foot wounds, functional partial foot amputations, such as transmetatarsal amputation, can preserve foot length and functional gait and avoid a below-knee amputation (BKA). When soft tissue is lacking, more proximal amputation has traditionally been performed. We evaluated the surgical and functional outcomes of free tissue transfer (FTT) for soft-tissue coverage following partial foot amputation in a highly comorbid population with chronic foot wounds.

Methods: A retrospective review of patients who underwent FTT after partial foot amputations from 2011 to 2021 was conducted. Primary outcomes included flap success, complications, limb salvage, and ambulatory status. Univariate analyses were performed, as well as multivariate regression analysis to identify independent predictors of secondary BKA.

Results: A total of 38 patients underwent FTT following partial foot amputation during the 10-year period. Average age and BMI was 57.0 years and 27.1 kg/m², respectively. Overall microsurgical success rate was 94.7% (n=36). At a mean follow-up duration of 24.9 months, the limb salvage rate was 81.6% (n=31) and ambulatory rate was 76.3% (n=29). There were no significant differences in demographics or comorbidities among the limb salvage group compared to the future amputee group. The salvage group had a higher prevalence of foorefoot wounds (74.2% v. 28.6%, p=0.034), while the amputee group had a higher prevalence of hindfoot wounds (57.1% vs. 16.1%, p=0.041). Independent predictors for secondary BKA included hindfoot wound location (OR 13.1, p=0.054), infection (OR 15.9, p=0.034), and partial flap necrosis (OR 26.9, p=0.024). 

Conclusions: FTT to a partial foot amputation site can offer long-term limb salvage to paitents with chronic non-traumatic foot wounds. Larger studies are warranted to further elucidate which paitents should be considered for partial foot amputations with FTT versus a higher level amputation initially.