Why the graft is not a ligament yet
When a surgeon replaces a torn ACL, they are not restoring the original ligament. They are placing a graft, typically taken from the patellar tendon or hamstring, that the body must slowly convert into functional tissue. This process is called ligamentization, and it takes between nine and twelve months under the best conditions. A 2016 study published in the American Journal of Sports Medicine found that athletes who returned to sport before nine months post-surgery had a re-rupture rate nearly eight times higher than those who waited until twelve months. The graft looks structurally intact on an MRI at three months. It is not. The collagen fibres are still remodelling, the nerve endings have not fully re-established, and the mechanical strength of the tissue is at its lowest point precisely when patients feel well enough to stop showing up to physiotherapy.
