Anatomical variations of the circumflex femoral arteries: a systematic review and meta-analysis of their prevalence and new classification of risk for surgical management

BACKGROUND AND INTRODUCTION: The femoral circumflex arteries (FCAs), arising from the femoral and profunda femoris arterial system, exhibit substantial anatomical variability and are clinically relevant due to their role in supplying the femoral head and proximal thigh musculature. These variations may affect surgical, vascular, reconstructive, and anaesthetic procedures in the femoral region. The objective of this study is to systematically evaluate the prevalence of FCA anatomical variants, characterize their patterns, and assess their clinical and surgical implications. METHODS: A systematic search was performed across PubMed/MEDLINE, Scopus, Web of Science, Google Scholar, CINAHL, and LILACS up to July 2025. Studies describing morphological or branching variants of the medial or lateral FCA were included. Methodological quality was assessed using the Anatomical Quality Assurance (AQUA) tool. A random-effects model estimated pooled prevalences and subgroup differences. Thirty-six studies met the eligibility criteria, of which twenty-nine contributed data to the quantitative meta-analysis. No significant laterality predominance was observed. Regional subgroup analysis demonstrated higher prevalence in European populations (33%, 95% CI: 25%-42%) relative to Asian populations (28%, 95% CI: 20%-36%). Sex-specific analysis showed a greater prevalence in females (72%, 95% CI: 59%-84%) than in males (42%, 95% CI: 29%-54%). Variations primarily involved origin, branching pattern, and course of the FCAs. CONCLUSIONS: Anatomical variations of the femoral circumflex arteries (FCA) are common and exhibit significant geographic and sexual variability. Based on this, we have proposed a classification of the probability of iatrogenic injury according to FCA variant and its relationship to the main surgical approaches to the hip.