My last blog discussed the diagnosis of ACL injuries. I think the last blog was very timely, as this has been really quite a season for what seems to me, an increased number of patients coming in with ACL tears from the mountains. The early abundant snow that we got in Tahoe, and now very icy condition with very little new snow may be one of the reasons for seeing more injuries. In any event, this blog will discuss various approaches to treating an ACL tear.
Once the diagnosis of an ACL tear is made, focus should be on regaining range of motion, swelling reduction, and return of basic function of the knee, i.e., walking, standing, and rehabilitating the quadriceps. The decision for surgery is really based on future goals in regards to sports, activities one likes to do, and current level of disability. What I mean by that is, is the knee strong and feel stable, or does it feel unstable and insecure particularly stepping off a curb or going down a stair? If the latter is true, I believe an ACL reconstruction is probably needed. If your plans are to pursue sports that involve pivoting and twisting, or you are young and want to continue with a very active lifestyle, most surgeons are currently recommending reconstruction. I was not to say that a very strong rehabilitation program focused on core strengthening, hamstring, and quadriceps balancing cannot allow one to get back to the same active lifestyle, provided they do not have significant looseness of their knee or laxity on examination. There are many happy patients have been those who did not have reconstruction and had an isolated ACL tear who do primarily straight head activities such as hiking, running, biking.
We have tried to find the ideal tissue to replace a torn anterior cruciate ligament. Repair does not work and long-term results are not good. One can use their own tissues or cadaver tendon. I remember when I did my fellowship in knee surgery, we even tried artificial ligaments such as Gore-Tex (yes, the same material that you wear) which initially did well, but all failed as they did not get a blood supply. Some are trying to use pig tendons, although personally I do not see an advantage to using a graft from a different animal over an allograft since there are still potential infectious disease concerns for nonhuman grafts.
For those deciding on pursuing an ACL reconstruction, there are two main sources of graft material. Basically, you can use your own tissues called autograft, and the most common tendons for these, are the patellar tendon or the hamstring tendons. The other option is in allograft or cadaver tendon, which is obtained from a deceased person who has donated their tissues. The tissues are cleansed and sterilized. There are a number of different ways to do that. Most are irradiated with low dose radiation to kill bacteria and viruses. The risk of infectious disease transmitted from an allograft is estimated to be 1 in 1.5 million.
The most important thing to my mind, about choosing an allograft, is that your surgeon is aware of what bank they are getting the tissues from, and that the banks are all certified by the American Association of Tissue Banks which ensures the highest quality of screening and harvesting techniques from the donors.
An autograft, or a graft from yourself, obviously carries no risk of infectious disease transmission, such as hepatitis or AIDS, but does “rob Peter to pay Paul.” The patellar tendon was very popular in the 1980, through the early part of 2000. Using the patellar tendon as a graft can leave patients with difficulty kneeling, with some softening of the cartilage under their kneecap, or trouble regaining full extension. Many of these problems have been corrected in recent years. Initially, it was felt that it had better fixation in the tunnels we drilled. More recent studies, however, show that there is no real advantage of patellar tendon over hamstrings, and that the results of using patellar tendon and hamstring autograft are nearly identical. The hamstrings on the other hand, make an excellent graft material and do not carry the risks of pain with kneeling, chondromalacia, r kneecap pain.
On the other hand, once in a very long while, a patient will notice some decreased strength in the hamstring which was harvested, but I can tell you that in my 25+ years of practice I have only had one patient who really complained about this significantly. Ultimately, the choice of which graft to use, I think really should be the preference of the surgeon (since you are really not shopping at Macy’s) with his or her own comfort level and expertise.
Postoperatively, most patients are back to walking with a fairly normal gait 4-6 weeks postoperatively or even sooner if they go into the surgery with really good quadriceps function and minimal swelling, and work very hard in the rehabilitation. This is so much different than 25 years ago when patients were placed in a plaster cast for six weeks and I remember as a resident, being made to hold the leg of a 250-pound football player while the plaster was being rolled to see if I was strong enough to do it as the first woman in UCLA’s orthopedic residency. One of my various “tests”. That’s a different blog, though.
The results of ACL reconstruction are really very reproducible and really depend on whether there has been any other damage in the joint such as meniscus tears, fractures, or loss of articular cartilage. The amount of arthritis one has at the time of injury, as well, will affect the outcome.
In regards to rehabilitation, there was an interesting paper that came out a few years ago that looked at patients that had intensive physical therapy, three times a week for approximately 8 weeks, compared to those that did a very focused home program and saw the therapist for 4 visits total and set up with a specific home exercise program. In fact, the outcomes were the same with a slight improvement in those that had a reduced physical therapy.
Motivation, consistency, and learning the popular rehabilitation is a very important factor in coming out with a good result. Letting Mother Nature mature the graft over time is also critical to the success of the operation, and we do know that those under age of 25 are much more likely to have their ACL reconstructions fail (15%) if they have an allograft. For that reason, I do not recommend using an allograft under the age of 25 unless there are some extenuating circumstances.
Complications from ACL surgery include infection (1 in 500), blood clot (1 in 400), stiffness, failure of the graft and recurrent instability (4-5%), anesthesia complications, scar tissue, bleeding, wound healing problems, numbness around the scars, and other rare complications such as pain, muscle weakness or arthritis. It is important to realize that the vast majority of patients do very well, and going into the operation as educated and committed to the rehab is one thing you can do to get the best result.
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Lesley J. Anderson, M.D.
