The blood supply of the patella is highly related to patellofemoral complications in total knee arthroplasty. The purpose of this study was to determine (1) the dominant blood supply for the patella and (2) the anatomic characteristics of the extraosseous and intraosseous vascularity of the patella.
In 13 fresh cadaveric knees, the femoral arteries were cannulated and perfused with a lead-based contrast agent. Patellae were harvested and scanned with a micro-computed-tomography scanner. The three-dimensional microarchitecture of the vascularity was reconstructed and evaluated. For the volumetric analysis, the vessel densities of the anterior, central and subchondral sides were compared.
A well-anastomosed prepatellar vascular network was found to cover the anterior surface of the patella, with main arteries from multiple directions, yielding 18.8 ± 3.1 (standard deviation) intraosseous branches into the patella. Along the intraosseous branches of the prepatellar vascular network, vessel density decreased (P < 0.001) by 0.54 ± 0.29% on the anterior side, 0.40 ± 0.24% on the central side and 0.23 ± 0.19% on the subchondral side. Arteries in the infrapatellar fat pad produced 5.1 ± 1.8 intraosseous branches, mainly located in the distal apex. Almost no arteries penetrated into the patella from the quadriceps tendon, patellar ligament or medial/lateral retinaculum.
The prepatellar vascular network is the dominant blood supply. Close exposure and extensive dissection around the patella should be avoided to preserve the prepatellar vascular network. The infrapatellar fat pad was recommended to be preserved when a lateral reticulum release was performed.