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Mandelbaum on Grafts, Biologics, and Rehab in ACL Repair

Bert R. Mandelbaum, MD, DHL (Hon)


January 21, 2016

In This Article


Recent years have brought significant improvements in anterior cruciate ligament (ACL) reconstruction, allowing surgeons to better address the specific needs of each patient.

As I outlined in my last column, decisions about how to approach an ACL injury depend on the patient's age, size, and plans for continuing sports. These factors also affect the choice of graft materials, whether to use platelet-rich plasma, and the approach to rehabilitation, which are discussed here.

Choice of Autograft Graft Material

The choice of graft material presents a complex challenge. First, there's the choice between autograft and allograft. Second, there's the choice of tendons to be harvested for grafting. Each has some advantages and potential disadvantages.

In autograft materials, the choices are patellar tendon, hamstring tendon (the semitendinosus and gracilis muscles), or quadriceps tendon.

Autologous patellar tendon is extremely durable and has been used for the past 30 years as the gold standard for ACL reconstruction in athletes. The downside is that harvesting this tendon can cause anterior knee pain and a higher incidence of osteoarthritis. I use it in my most competitive athletes who put the greatest stress on the joint.

Using autologous hamstring tendon avoids anterior knee pain. And these tendons are easier to harvest. On the downside, many athletes never quite get back to full strength after this important tendon is harvested. And the injury to the hamstring can cause an imbalance of strength in the joint, increasing the risk for reinjury, especially in females.

Autologous quadriceps tendon has become more popular in the past 2-3 years because it's a thicker tendon; you don't get anterior knee pain from harvesting it, and it doesn't seem to have to the failure rate associated with hamstring tendon. It's also fairly easy to harvest. So it has many of the advantages without the disadvantages.

The obvious advantage of allografts is that they come from cadavers, so harvesting the graft doesn't injure the donor. Allografts may come from a patellar tendon, hamstring tendon, quadriceps tendon, or tendons of the foot. Historically, allografts used in ACL reconstruction have failed at a higher rate than autografts. The biggest factor has been radiation for sterilization, which weakens the graft. Washes, detergents, and vacuum techniques can effectively sterilize the graft without compromising its strength.[1,2]


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