Relationship between hypovascular zones and patterns of ruptures of the quadriceps tendon

Background: Compromised vascularity and hypoxia have been proposed as risks for tendon ruptures. The density of vascularity of the quadriceps tendon may explain the pattern of ruptures of this muscle-tendon unit. Methods: Twenty adult human cadavers underwent whole-body arterial perfusion with a mixture of lead oxide, gelatin, and water through the femoral artery. Thirty-three quadriceps tendons were dissected and radiographed, and each angiogram was analyzed with use of image statistical software. Results: We consistently identified a hypovascular zone located between 1 and 2 cm from the superior pole of the patella. This finding correlates with the location of spontaneous ruptures of the quadriceps tendon reported in the literature. These findings indicate that the vascular supply of the quadriceps tendon is separated into three arcades, or arches, which are medial, lateral, and peripatellar. Conclusions: Hypovascularity may determine the site of spontaneous ruptures of the quadriceps tendon. Clinical Relevance: Understanding the vascular zones of the quadriceps tendon may facilitate the use of nonoperative as well as operative treatments to increase the vascularity of the tendon. An understanding of the vascular arcades may facilitate and enhance healing following reparative and reconstructive surgery on the tendon.