March 2010 Newsletter

Archived Newsletters

Anterior Cruciate Ligament (ACL) Graft Selection
By Dr. Stephen A. Hunt

You’ve just been told you have a torn ACL. Your doctor recommended reconstructive surgery, and talked about the procedure, the rehabilitation, and then said something about choosing a graft. Your doctor discussed the pros and cons of the different graft options and gave you a recommendation. However, by that point in the discussion, you were still thinking about what an inconvenience this whole thing is, and don’t recall anything that was said about the different types of grafts. We can clear things up for you, by providing answers to the questions below to provide you with some basic information about ACL graft options. We are not recommending a specific graft. That is a discussion for you and your surgeon.

What is an ACL graft?
An ACL graft is a tissue scaffold used to reconstruct a torn ACL Ligament. It restores stability to the knee by re-establishing a central connection between the femur (thigh bone) and the tibia (shin bone).

What are the different types of graft?
There are many types of graft options.
Autografts are tissues that are taken from your body.
Allografts are tissues taken from a cadaver (organ donor).

What are the types of autograft?
The most common autograft tissues are the central 1/3 of the patella tendon (harvested with a small piece of bone from the kneecap and the shin bone) and the hamstring tendons. A small number of surgeons use the central portion of the quadriceps tendon with or without a small piece of bone from the kneecap.

What are the types of allograft?
Allograft tissues can be completely soft tissue, like hamstring tendons or leg tendons, they can be some bone and soft tissue like Achilles tendons, or they can have two bony attachments like patella tendons.

Is one graft stronger?
All the grafts have strengths that exceed that of the native ACL, so all can function very well as ACL grafts, which is why all are offered.

What are the benefits of using my own tissue (an autograft)?
Autografts are cheaper, carry no risk of disease transmission, incorporate into the bone quicker than allografts, and have a slightly lower risk of re-tearing (especially in young patients).

What are the benefits of cadaver tissue (an allograft)?
Allografts allow for smaller incisions (better cosmesis), less early postoperative pain, less potential injury from graft harvest, decreased surgical time, and allow for larger tissue bundles. Additionally, if you are older and have some early arthritis, allografts reduce the chance that a graft harvest will exacerbate some of your underlying knee issues.

I don’t want dead tissue in me!
Essentially all tissue grafts are dead when they are used in an ACL reconstruction. The blood supply to an autograft is disrupted during the graft harvest. Autografts and allografts provide a scaffold for your body to repopulate and create a living ligament – that is why recovering from this procedure takes so long. Rejection from allograft is not an issue for ACL reconstruction. If you are confused, it is not without good reason. There are a multitude of studies over the past several decades on ACL reconstruction procedures. It is possible to select studies to bias the decision one way or another. However, most large studies demonstrate little significant differences between grafts. Below is a summary of some of the pros and cons of each graft option that we offer – based on reports in the literature – for you to discuss with your surgeon:

	PRO	CON
Autograft
Hamstring	Better cosmesis Stronger graft Low risk of Anterior knee pain	Hamstring weakness Fixation Slower graft incorporation (soft tissue to bone)
Patella Tendon	Bone to bone healing Better initial fixation	Larger incision Increased anterior knee pain/stiffness
Allograft	No graft harvest Large grafts available	Slower healing Disease transmission Higher failure rate in young patients Cost

In summary, there are several good options for grafts to use for an ACL reconstruction. All have reported benefits and risks. Ultimately, you and your surgeon should discuss these together and your surgeon may have experience that will lead to a recommendation for use of one option over another.

For more information, please see the American Academy of Orthopaedic Surgeons website for patient information: http://orthoinfo.aaos.org/

References

1. Prodromos CC et al. Controversies in soft-tissue anterior ligament reconstruction: Grafts, bundles, tunnels, fixation, and harvest. J Amer Acad Ortho Surg 2008; 16: 376-384.
2. West RV and Harner CD. Graft selection in anterior cruciate ligament reconstruction. J Amer Acad Orthop Surg 2005; 13: 197-207.