The patellar tendon bone-tendon-bone graft has been the "gold standard" graft choice for ACL reconstructions since it became common practice in the mid-1980. It has been used extensively by surgeons since that time and still remains the graft of choice for a high number of orthopedists who perform this surgery regularly. The patellar tendon graft has consistently demonstrated excellent surgical outcomes with a 90-95% success rate in terms of returning to pre-injury level of sports. A patellar tendon graft is harvested through a 3-4" long incision based just along the medial border of the tendon... The middle third of the tendon 10-11 mm wide is then removed along with 2-2.5 cm long bone blocks still apart of the tendon at each end of the graft from the tibial tubercle and the outer surface of the patella. This gives a composite bone-tendon-bone graft that has very strong insertion points of the tendon soft tissue into bone. The tensile strength of this graft has been measured by Noyes (1984) to be about 2950 Newton’s to failure, versus the strength of an intact ACL at 2160 N.
What happens to the remaining patellar tendon after a third of it has been removed? Over the course of three to four months after surgery the tendon regenerates or "grows back". Initially it seems to overgrow into a thick, large tendon that then remodels back to a more normal contour by 12-18 months postoperatively. Surgeons have even been able to re-harvest another patellar tendon graft from the original tendon once enough time has passed for tendon reconstitution (although there's now evidence that this repaired tissue may not be as strong as normal patellar tendon tissue). Patellar tendon ruptures at the donor site are unlikely after the first few months post-op. Patellar tendon ruptures can and do occur however during the initial 6-8 weeks after surgery if the remaining tendon is stressed too hard.
One of the advantages of this construct is that because the