Morphometric mapping of ACL femoral footprint variability: implications for personalized anatomic single-bundle reconstruction

While the Ribbon Theory has challenged traditional two-bundle anatomy, the clinical translation of ACL morphological variability remains unclear. The field is evolving from "anatomic" toward "Precision Anatomic Reconstruction,"which motivates the development of quantitative criteria for individualized surgical planning.

Thirty fresh-frozen cadaveric knees (15male, 15female) underwent standardized low-temperature perfusion preservation and comprehensive 3D morphometric analysis. Correlations between footprint characteristics and anthropometric parameters were evaluated.

Ribbon-like morphology predominated (80%), yet substantial inter-individual variability existed in footprint morphology:oval (66.7%), teardrop (23.3%), and irregular (10.0%).Males demonstrated significantly larger footprint area than females (144 ± 19 vs. 124 ± 18 mm², p < 0.01). Critical finding: Footprint area correlated strongly with ACL width (r = 0.72, p < 0.001), but not with height or weight. Conventional round tunnels (9 mm) provided only 47.5% footprint coverage, creating a significant "coverage gap."

ACL morphology exhibits high heterogeneity that cannot be predicted by anthropometric measures. This study advocates for a paradigm shift towards Precision Anatomic Anterior Cruciate Ligament (ACL) Reconstruction, emphasizing that oval large footprints may suggest consideration of elliptical tunnels and rectangular grafts. Additionally, it identifies that true two-bundle phenotypes, comprising 13.3% of cases, along with intermediate phenotypes, accounting for 6.7% (a combined total of 20%), may still benefit from the consideration of double-bundle techniques. For the small subgroup of irregular footprints (10%, n = 3), anatomical observations from this limited-size cohort raise the hypothetical possibility of using three-dimensional-printed patient-specific guides and AI-assisted preoperative planning. Further validation in larger study populations is required before clinical application.