There are many different kinds of tissue grafts that can be used to repair a torn or ruptured anterior cruciate ligament (ACL). The bone-patellar tendon-bone (BPTB) is called the "gold standard." It's used the most with the best results.
The graft is made up of the middle third of the patellar tendon and a piece of bone on either end. The bone is taken at one end from the kneecap and at the other end from the lower leg bone (tibia).
This graft works well because the patellar tendon has a high strength and stiffness. The bone plugs make it possible to get a good solid hold with screws to keep it in place. The graft seems to take hold quickly.
There are a few problems with the BPTB. Some patients have pain and swelling where the graft is taken from. It can be very difficult to kneel. Other patients report numbness, most likely caused by damage to a branch of the saphenous nerve. Loss of quadriceps muscle strength and even fracture of the patella are also possible problems.