Does Resection Length Dictate Reconstruction Type? Systematic Review of Biological Reconstruction Methods After Oncologic Intercalary Resection in Children and Young Adults

Limb salvage surgery is the preferred treatment for pediatric bone tumors in the lower extremity when free margins can be achieved, particularly when adjacent joints can be preserved. Nevertheless, intercalary bone defects remain challenging. Common bio-logical reconstruction techniques include massive allograft, free vascularized fibular graft (FVFG), and the Capanna Technique (allograft combined with FVFG). This review summarizes current evidence on the proportion of complications associated with these techniques, with emphasis on non-union in relation to defect length. Finally, we propose directions for future research to refine patient selection for biological reconstruction. A systematic review was conducted using PubMed, Scopus, Embase, and Cochrane Library. Eligible studies reported outcomes of allograft, FVFG, or the Capanna technique for intercalary lower limb reconstruction in children or adolescents and reported on defect length. Fourteen articles met the inclusion criteria: two on allograft, two on FVFG, and ten on the Capanna technique. In total, 181 patients were included (allograft: 17, FVFG: 16, Capanna: 148 patients). Mean defect lengths were 15.5 cm (allograft), 11.4 cm (FVFG), and 15.0 cm (Capanna). Average union times were longest with allograft (15.5 months) and shortest with FVFG and Capanna (11.4 and 11.6 months). The Capanna technique demonstrated the lowest non-union proportion (16.5%), compared with FVFG (25%); non-union data of the allograft were inconsistently reported. Fractures and infections were least common in the Capanna group. The reconstruction strategy should be tailored to defect size, anatomical location, and patient-specific factors. The Capanna technique appears most favorable for larger defects in the lower extremities, but its potential role in smaller defects warrants further investigation.