Revascularization of a Human Anterior Cruciate Ligament Graft During the First Two Years of Implantation

The blood supplies of 45 unimpinged, human anterior cruciate ligament grafts were studied during the first 2 years of implantation. Grafts were defined as unimpinged by the low signal intensity of the graft observed on a sagittal proton density magnetic resonance scan. Magnetic resonance imaging with the intravenous contrast agent gadolinium diethylenetriamine pentacetic acid was used to evaluate the blood supply of the hamstring autograft as well as the periligamentous tissues by assessment of enhancement patterns after administration of the agent. The unimpinged anterior cruciate ligament graft acquired no discernible blood supply during the 2 years of implantation. The graft retained the same hypovascular appearance as the normal posterior cruciate ligament. In contrast, the periligamentous soft tissues were richly vascularized and covered the graft by 1 month. The viability of an unimpinged, human anterior cruciate ligament graft may depend more on synovial diffusion than on revascularization.