Comparing Results of Grafts Used for ACL Reconstruction

Anyone facing the prospect of anterior cruciate ligament (ACL) reconstructive surgery will be faced with one major decision. And that is: what type of graft should be used? In some cases, surgeons may just make that decision for the patient. However, more and more consumers want to participate in this type of decision-making.

But there's no clear-cut, single answer to what type of graft should be used. Each one has its advantages and disadvantages. To help surgeons and patients alike, the authors of this article reviewed all studies published to see what the current evidence suggests.

To begin with, it helps to understand there are allografts and autografts. Allografts refer to tissue from a donor bank. The major disadvantage of an allograft is the body's tendency to reject tissue it considers "foreign" or "nonself."

But the advantages are great in that the patient does not suffer pain or infection at the donor site. There is a faster healing time with only one wound to heal. And for some people for whom appearances are important, one less scar is worth the risk of using someone else's tissue for the procedure.

Autografts refer to tissue harvested from the patient. There are three places the autograft (donor) tissue usually comes from: 1) bone-patellar tendon-bone (BPTB), 2) hamstring tendon, and 3) quadriceps tendon. As you might guess from what has been said so far, the donor site can cause a more painful response than even the primary surgical site.

Patients who have tendon harvested from the front of the knee (two of the three options) can end up with pain along the front of the knee. The painful symptoms can be severe enough to keep them from being able to bend the knee fully or kneel down. That may not sound like much of a problem until you can no longer bend down to tie your shoe, tend a garden, play with grandchildren, or slide into home plate for an athlete.

Given the fact that anterior cruciate ligament ruptures are very common injuries requiring surgery, you might think the decision about which graft tissue is best would be decided by now. But in fact, despite many studies comparing these different approaches, there are still many unknowns and gray areas.

That's because different studies use a variety of different outcomes to measure results by. They also don't follow-up with patients for the same length of time after surgery. Some results may be reported after six months, one year, or two years while others extend outcome measures up to 10-years.

Another factor involves rehabilitation programs. Post-operative protocols may differ from one surgeon to another contributing to differences in results. Not to mention the fact that some patients are athletes who rehab differently while preparing to get back into their sport activity. They may count whether or not they return to full participation in their sport as the litmus test for a successful result.

Not only that but there are different ways to attach each graft type adding to the complexity and challenge for the surgeon in deciding which way to go. Many patients do choose which graft type they want so they aren't randomly put in treatment groups and compared. This can create a treatment bias.

To help compare each technique used from study to study, the authors of this study used seven basic measures. These included knee stability, leg strength, function, return-to-sports, patient satisfaction, complications, and cost. Here's what they found to help you with your decision.

When it comes to post-operative knee joint stability (joint "give", laxity, or looseness versus tightness of the joint) it looks like there's no difference between allografts and autografts. The primary difference is in terms of rupture rate. Improper preparation of allografts (e.g., sterilization, drying) can result in more graft ruptures years later compared with autografts.

Concerning muscle strength. There is agreement among studies that quadriceps strength seems to be equal among the various autografts. The hamstring muscle group is more likely to lag behind in recovering full strength, especially for patients who have a hamstring graft.

Return of overall function seems to be equal among all graft types. But return-to-sports varies widely. The majority of patients (75 per cent) get back to playing but not all return to their preinjury level of participation. Some athletes have to gear down to a lower intensity level of activity while others change the sports activity altogether.

One more area of concern and comparison is complications (e.g., pain, infection, graft failure or rupture). Most patients expect a certain amount of pain right after surgery. But when pain lasts months-to-years later, this symptom becomes a complication. Kneeling pain persists more often with patellar donor grafts. Other long-term annoying symptoms at the harvest site can include numbness, tenderness, or irritation.

Results also showed that infection rates are not higher with allografts. Disease transmission from allograft (donor) tissue (e.g., hepatitis, HIV) occurs in less than one out of every 1.6 million patients.

Finally, graft failure or rupture is more likely occur when there is significant joint laxity (looseness) after surgery. Another significant risk factor is return to sports that require sudden turns or changes in direction (pivoting), sidestepping, and jumping. Studies show that younger, more active patients are the most likely to experience ruptures with an allograft.

In the end, patient satisfaction is rated high (in the 90 percentile) no matter what type of graft is used. If you take cost into consideration, the autograft is less expensive than the allograft. This is due to the cost of the donor tissue (can be as much as $1,000).

In summary, when deciding graft type for ACL reconstruction surgery, each individual patient must make his or her decision about graft type based on known pros and cons of each graft type and technique. This decision is based on age, type of physical activity level desired after surgery, surgeon recommendation, and awareness of advantages, disadvantages, complications, and costs of each procedure.

Reference: Alec A. Macaulay, MD, et al. Anterior Cruciate Ligament Graft Choices. In Sports Health. January/February 2012. Vol. 4. No. 1. Pp. 63-68.

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