A Novel Description of Medial Meniscus Vascularization: A Multicenter Study Introducing the “Medial Meniscal Artery”

BACKGROUND: The microvasculature of the human meniscus has been previously described by Arnoczky and Warren. However, to date, the qualitative and quantitative extra-articular vascular anatomy of the medial meniscus has not been characterized. PURPOSES: To perform a qualitative and quantitative anatomic study of the extra-articular medial meniscal vasculature and to introduce the novel "medial meniscal artery" (MMA), potentially providing future guidelines for the treatment of meniscal abnormalities. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 33 unpaired, frozen human cadaveric knees were dissected. The femoral artery was identified and cannulated using an angiocatheter. The arteries were perfused with a red acrylic paint solution, allowing for improved visualization. Artery dimensions and distances were measured using a digital caliper. Perfused specimens were imaged using computed tomography and segmented using 3D reconstruction software to identify vessels and repeat artery measurements digitally. RESULTS: The MMA was consistently identified in all specimens. In 27 (82%) of 33 specimens, the MMA branched directly from the popliteal artery; in 5 (15%), the MMA shared a common trunk with the inferior medial genicular artery; and in 1 specimen (3%), the MMA shared a common branch with the inferior lateral genicular artery. The MMA was easily distinguishable from the superior, inferior, and middle genicular arteries, given its direct course to the medial joint line with terminal branches to the posterior horn of the medial meniscus and deep to the semimembranosus tendon. The MMA exhibited a consistently smaller vessel diameter relative to the genicular arteries. CONCLUSION: This is the first study to identify and quantitatively describe the MMA in the human knee. The MMA can be identified consistently on gross anatomic dissection in cadaveric donors of varying demographics. Further research is needed to identify and characterize the artery in vivo and to determine the MMA's role in meniscus preservation surgery. CLINICAL RELEVANCE: The findings of this study will provide future avenues of research toward understanding medial meniscus vascularization and the genesis of potential degenerative changes when vascularization is poor. This will help to further refine diagnostic and treatment options for meniscus revascularization and compartment preservation. Additionally, this study may help define safe zones in the knee during posterior approaches and expand the base of knowledge for emerging vascular procedures such as genicular artery embolization.