Abstract
PURPOSE: Compare functional, oncologic, and complication outcomes of distal femoral reconstruction after malignant tumor resection in children <12 years, in whom adult implants are unsuitable. METHODS: Preferred Reporting Items for Systematic Reviews and Meta-Analyses-guided systematic review and meta-analysis of PubMed, Embase, Scopus, Web of Science, and Cochrane (inception-January 1, 2025). Eligible studies reported outcomes for expandable or non-expandable prostheses, osteoarticular allograft, allograft-prosthetic composite, epiphyseal-preserving reconstruction, rotationplasty, arthrodesis, spacers, or amputation. Random-effects models pooled means/proportions; risk of bias was assessed using the Newcastle-Ottawa Scale; and certainty was assessed using GRADE. RESULTS: Forty-one studies (n = 1186) met criteria. Pooled mean Musculoskeletal Tumor Society was 24.9/30 (95% confidence interval, 23.9-25.9; I (2) = 97%). Biological joint-preserving methods and rotationplasty tended to yield the highest function; arthrodesis and amputation were lower. Local recurrence was 5.2% (95% confidence interval, 3.3-7.1) without differences between techniques. Five-year overall survival was 81.6% (76.6-86.6); epiphyseal-preserving reached 93.3%, expandable prostheses 79.0% (contextual, not causal). Complications differed: expandable prostheses had reoperation rates of 57.2% and mechanical failure of 42.3%; osteoarticular allograft had a fracture rate of 27.4% and failure rate of 37.5%; allograft-prosthetic composite had a failure rate of 24.4% and nonunion rate of 13.5%; and arthrodesis had the fewest complications. Deep infection was 6.7%. GRADE certainty was as follows: high for local recurrence; moderate for 5-year survival and infection; and low for function and reoperation/failure (heterogeneity, retrospective design). CONCLUSIONS: Reconstruction should be individualized, prioritizing function and complication risk; oncologic outcomes appear driven by tumor biology/systemic therapy. Heterogeneity and inconsistent failure definitions limited cross-technique comparisons and precluded pooled implant survival. SIGNIFICANCE OF STUDY: Our pooled estimates offer practical reference points for counseling families about function and complications across reconstruction options in children aged <12 years while highlighting priorities for standardized reporting and coordinated prospective research.