Free fillet upper extremity flap reconstruction after forequarter amputation: A systematic review and meta-analysis.

Background: Forequarter amputation and related shoulder-girdle ablative procedures create extensive defects, often in previously irradiated fields. "Spare-parts" reconstruction using tissue from the amputated limb, most commonly the free fillet upper-extremity flap (FFUE), offers donor-site-sparing coverage. The reliability and complication profile of FFUE reconstruction remain uncertain because evidence is limited to small series and case reports. Methods: A PRISMA 2020-compliant systematic review and meta-analysis was conducted. PubMed, Scopus, and Embase were searched on 25 Nov 2025 using prespecified strategies, yielding 404 records; after deduplication and screening, 17 studies were included. We included studies reporting microvascular transfer of an upper-extremity fillet flap (forearm/arm/hand, with or without bone) to reconstruct defects created by forequarter amputation, interscapulothoracic amputation, or shoulder disarticulation. Primary outcomes were complete flap survival, any postoperative complication, and reoperation. Random-effects meta-analyses of proportions were performed using a generalized linear mixed model (GLMM) with logit link; τ and prediction intervals were reported. Sensitivity analyses used inverse-variance pooling with Hartung-Knapp adjustment. Results: Seventeen studies encompassing 44 patients met inclusion criteria. Most reconstructions followed forequarter amputation (86.4%) for malignant disease, frequently after prior radiotherapy and/or chemotherapy (75.0%). The pooled rate of complete flap survival was 97.0% (95% CI 88.8-99.3), with no reported total flap losses and one case of partial distal necrosis (2.3%). Any postoperative complication occurred in 31.2% (95% CI 18.7-47.3), and reoperation in 26.0% (95% CI 14.6-42.0). The most common complications were necrosis (16.1%), thrombosis (6.8%), and wound dehiscence (6.9%). Despite substantial heterogeneity and frequent prior multimodal therapy, free fillet upper-extremity flaps demonstrated consistently high reliability across reported series. Conclusions: FFUE reconstruction shows near-universal survival despite extreme defects and frequent prior multimodal oncologic therapy. Complications and reoperations are not rare but appear acceptable in context. Standardized reporting and multi-institutional collaboration are needed to define best practices and to evaluate patient-centered outcomes.