Abstract
Background and Objectives: Post-amputation flap necrosis in diabetic foot patients is associated with a high risk of reamputation, level-up amputation, and limb loss. Intralesional epidermal growth factor (iEGF) has been shown to promote wound healing in diabetic foot ulcers; however, its role in the management of post-amputation tissue defects and flap necrosis remains unclear. This study aimed to evaluate the association between iEGF use and clinical outcomes in diabetic foot patients with post-amputation flap necrosis and to characterize longitudinal changes in wound macrophage-associated cell populations. Materials and Methods: This single-center observational cohort study, with retrospective identification of eligible patients and longitudinal follow-up, included 164 diabetic foot patients who developed flap necrosis, wound-healing disorders, or tissue defects following transmetatarsal, Lisfranc, Chopart, or below-knee amputations. Eighty-four patients received an iEGF-containing multidisciplinary limb-salvage strategy, while 80 patients received a multidisciplinary limb-salvage strategy without iEGF. The primary endpoint was treatment success, defined as preservation of the original amputation level without reamputation or proximal level-up amputation, together with satisfactory wound healing at the last available clinical follow-up. Secondary endpoints included mortality during follow-up and, in a flow cytometry sub-study of 12 iEGF-treated patients with available paired wound samples, changes in CD38+ and CD209+ cell proportions within the CD45+CD14+ macrophage-enriched population in paired wound-tissue samples. Results: Overall treatment success was 68.3% (112/164), and the observed crude cumulative mortality proportion was 21.3% (35/164). Treatment success was higher in the iEGF group than in the control group (95.2% [80/84] vs. 40.0% [32/80], p < 0.001), whereas the observed crude cumulative mortality proportion was lower (2.4% [2/84] vs. 41.3% [33/80], p < 0.001). In the flow-cytometry sub-study (n = 12), CD38+ cell proportions within the CD45+CD14+ macrophage-enriched population increased from 10.8% to 20.3%, whereas CD209+ cell proportions increased from 14.5% to 25.7% in paired samples collected before and after the iEGF treatment cycle (both p < 0.001). Conclusions: In this observational cohort of high-risk diabetic foot patients with post-amputation flap necrosis, wound-healing disorders, or tissue defects, iEGF administered as part of a multidisciplinary limb-salvage strategy was associated with higher treatment success, while a lower crude cumulative mortality proportion was also observed in the iEGF group. The mortality difference represents a crude cumulative comparison and should not be interpreted as evidence of a time-adjusted or treatment-associated survival benefit. Given the non-randomized treatment allocation, differences in vascular management and adjunctive therapies, and the potential for residual confounding, these findings should be interpreted as associative rather than causal. The paired tissue substudy demonstrated pre–post changes in CD38+ and CD209+ cell populations; these exploratory findings do not establish macrophage polarization or a causal biological mechanism.