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Objectives and questions: Historically, the limited intrinsic healing capacity of anterior and posterior cruciate ligament (ACL and PCL) injuries has been attributed, in part, to the presumed low vascularity of these intra-articular structures and a consequent lack of reparative tissue formation. Although biomechanical and functional factors also influence healing, quantitative, region-specific comparative data on ACL versus PCL vascularity remain scarce. Accordingly, the purposes of this study were (1) to quantitatively map the regional arterial supply of the ACL and PCL in a fresh-frozen human cadaveric model across standardized anatomical regions using 7-Tesla quantitative magnetic resonance imaging (7T-qMRI), histology, and high-resolution micro–computed tomography (micro-CT), and (2) to directly compare vascular distribution patterns between the two cruciate ligaments.

Material and methods: Seven fresh-frozen human cadaveric knee pairs (mean age, 41.9 ± 15.5 years) underwent limited vascular dissection and arterial cannulation. Ligament vascularity was quantified using pre- and post-contrast 7T quantitative MRI (7T-qMRI) with a volumetric interpolated breath-hold examination (VIBE) 3D T1-weighted gradient-echo sequence, and contrast enhancement served as a surrogate for arterial supply. Ligament regions were defined by relative distance from the distal insertion: zone I (>90%), zone II (75–90%), zone III (25–75%), zone IV (10–25%), and zone V (<10%). Subsequently, an algorithm-based quantitative histologic analysis of hematoxylin and eosin (H&E)–stained sections was performed for validation of 7T-qMRI measurements, and two additional specimens underwent high-resolution (98 μm) micro-computed tomography (micro-CT) for qualitative assessment of vascular architecture.

Results: 7T-qMRI demonstrated distinct, region-specific arterial distribution profiles, with predominantly proximal contributions in the ACL and more distal vascularity in the PCL. In the ACL, relative contributions were 12.3% at the femoral enthesis and 87.7% at the tibial enthesis, with zone-wise contributions of 10.2% (Zone I), 25.9% (Zone II), 24.9% (Zone III), 10.3% (Zone IV), and 17.6% (Zone V). In the PCL, contributions were 23.1% at the femoral enthesis and 76.9% at the tibial enthesis, with zone-wise contributions of 9.3% (Zone I), 13.2% (Zone II), 16.7% (Zone III), 21.8% (Zone IV), and 39.6% (Zone V). Overall arterial contribution within the soft-tissue zones differed significantly between ligaments (ACL, 8.3% vs PCL, 27.1%; p = 0.016), and zone-level comparisons identified significant inter-ligament differences in Zone II and Zone IV (p = 0.046 for both).

Discussion and conclusions: This study demonstrates distinct, region-specific arterial distribution patterns in the ACL and PCL. The ACL showed predominantly proximal arterial supply, whereas the PCL exhibited greater distal and overall arterial contributions. These quantitative differences in vascular organization provide a biological framework that may help explain ligament-specific healing potential.