Abstract
PURPOSE: This study aimed to quantitatively assess relative arterial contributions to the quadriceps tendon (QT) using 7-Tesla quantitative magnetic resonance imaging (7T-qMRI), histology and high-resolution computed tomography (micro-CT) in a fresh-frozen human cadaveric model. METHODS: Six human cadaveric knee pairs were obtained (mean age: 43 years; range: 23-61 years). Pre- and post-contrast 7T-qMRI scans were performed to quantify tendonous vascularity. Subsequent algorithm-based quantitative histologic analysis was performed using hematoxylin and eosin staining, with validation by CD31 immunohistochemistry. Qualitative analysis was performed on two additional knee specimens using 98 μm micro-CT imaging. RESULTS: The distal QT demonstrated higher median arterial contributions versus central and proximal regions (distal, 47.4% [interquartile range: 30.8%-64.1%]; central, 28.6% [20.4%-41.5%]; proximal, 11.6% [8.7%-18.4%]), with significantly greater contributions distally versus proximally (Cohen's d = 1.58; p = 0.021). These findings aligned with the sagittal sub-analysis (deep-proximal 17.2 ± 19.3% vs. deep-distal 43.4 ± 20.3%; Cohen's d = 1.32; p = 0.050). Histologic analysis (interobserver-reliability: r = 0.95) corroborated the MRI results (distal QT, 43.5 ± 7.9%; central, 30.7 ± 6.4%; proximal, 25.8 ± 4.1%), with significant differences between distal and both proximal (Cohen's d = 2.81; p < 0.001) and central (Cohen's d = 1.78; p = 0.012) regions. The deep layer was found to have significantly higher arterial contributions (61.6 ± 14.2%) versus the superficial layer (38.4 ± 14.2%) (Cohen's d = 1.64; p = 0.018). The medial and lateral QT demonstrated lower arterial contributions versus middle QT (Cohen's d = 0.96-1.26; p > 0.050). CONCLUSION: 7T-qMRI and algorithm-based histological analysis of arterial QT contributions revealed significantly greater arterial contributions in the distal compared to the proximal as well as in the deep compared to the superficial region. While the central region demonstrated higher arterial contributions than the medial and lateral aspects, these differences were not statistically significant. Given that the majority of injuries affect the distal and central portions of the QT, these findings reinforce the rationale for direct tendon-to-bone repair; however, clinical studies are necessary to confirm these findings. LEVEL OF EVIDENCE: Level V, cadaveric study.