Anterior Cruciate Ligament (ACL) Ruptures

Tearing your ACL can be a major life event and has lasting implications for the recreational and professional athlete for the rest of their lives.  That is why it is incredibly important to be educated going into the surgeon’s office, ask the right questions, and have an understanding what the recovery and long-term implications are for your knee. I will briefly discuss the mechanism of injury,  symptoms of an ACL tear, predictors for surgical outcomes, pre-operative counseling for graft options,  details of surgery, bracing, and recovery/return to activity.

So if you are reading this it is likely that you or someone you know sustained an ACL injury.  It could have been a contact or non-contact injury usually occurring from a hyperextended position of the knee.  Patient’s often complain of feeling a pop in their knee, but not always.  Due to the disrupted blood supply to the ACL the knee usually gets incredibly swollen the night of the injury due to blood in the knee-otherwise known as a hemarthrosis. In cases where the ACL is strained or incompletely torn (one of two bundles of ACL tears) there is not always an associated hemarthrosis.  The ACL’s primary function is to stabilize the knee and prevent the knee from “buckling” and feeling like it will give-way.  The ACL is not able to be repaired although we tried this in the 70’s and 80’s and it failed. Recently there has been a handful of surgeons who are advocating repairing the ACL in specific type of tears and even augmenting the repair with biologic “stem cells” but the data doesn’t show this is better than reconstructing the ACL in most surgeons hands.  I have performed ACL repairs in the past but do not recommend it at this time. Therefore, I will focus on ACL reconstruction and the different graft options available.

The success of ACL surgery is dependent on so many variables. If you search the medical literature on ACL injuries there are 16,210 articles which makes drawing conclusions on the best treatment for ACL tears difficult to interpret. The MOON consortium is a nationwide group of institutions and surgeons that have helped guide the ACL surgeon for the best possible patient outcomes. That is why I will focus on this data to summarize my thought process when I am discussing ACL surgery with you.

The most important factor in ACL surgery success is having a fellowship-trained sports surgeon who performs ACL reconstructive surgery often and is confident to put the ACL tunnels in the right place with sound fixation, and  with the right tension. The number one reason for ACL graft failure is surgeon error.  I am confident that I will perform the right surgery for you as I have performed nearly 1000 ACL surgeries with all different grafts and with the most cutting-edge techniques. However, it is not just my surgery that will predict your success, but it will also depend on you, the patient, following the rehabilitation protocol and returning to your sport when your therapist and I decide you are ready. There is no set timeline for this and depends on you meeting return to play criteria and some studies suggest it can be more like 9 to 12 months versus the classic 6 months most surgeons have suggested.

Graft options can be daunting when there are friends, family members and surgeons who all have different experiences, have different grafts-if they had surgery-, and have different experiences. Every patient and every injury is unique.  Success of surgery sometimes has nothing to do with the graft and can depend on things I discussed in the previous paragraph.  The MOON consortium has told us that the status of the meniscus and cartilage has a lot to do with the success of your surgery.  It not uncommon to have a meniscus tear when you tear your ACL.  It is also not uncommon to have a “bone bruise” on MRI which shows us that there is always some underlying cartilage injury with an ACL tear.  Finally, not every ACL is created equally, as there can be injury to any of the 3 other ligaments in the knee and this is considered a multi-ligamentous knee injury and outcomes are more guarded after these injuries. So don’t compare your knee to anyone else’s surgical experience because it is like comparing apples to oranges in some circumstances.

I will simplify graft options for you by telling you my thought process which is based on the literature.  These are general guidelines and there are always individual exceptions and special circumstances which I will not cover here, Autograft is using your own tissue versus allograft which is viral and bacterial- free cadaver tissue.  My opinion is to use autograft whenever possible. Studies have shown that age younger than 25 the risks of re-rupture is anywhere between 3-8x more likely with allograft.  Therefore, no-brainer: age<25 autograft. After the age 25 literature would tell us that allograft and autograft outcomes are no different.  I recommend allograft for my >35 yo patients who are relatively active and want a slightly easier recovery but not shorter recovery. I also use allograft for some of my multi-ligamentous patients. I am 43 soon and if I tore my ACL I would probably get an allograft at this point in my life ;).

Here I will briefly focus on the three autograft options: bone tendon bone (BTB) aka patellar tendon graft, hamstring tendons, and finally quadriceps tendon.  I am facile and able to do any of the three for you; I most commonly perform BTB for most of my athletes and I refer to it as the NCAA/NFL gold standard.  Suffice it to say, studies have shown all three of these grafts are equivalent to one another if performed successfully. So don’t stress about the graft, just go with what potential downside of the graft you could live with and what graft your surgeon is most comfortable performing,  As a side note, all the graft options are at least twice as strong as your native ACL tissue was before you tore it! Briefly, I will mention the most common complication with each graft. The downside of BTB is kneeling pain from me removing a plug of bone from the knee cap (patella) and shin bone (tibia).  The downside of hamstrings is weakness in deep knee flexion, probably only noticed by elite athletes, and the possibility your hamstrings are too small to use and need to be augmented with cadaver tissue.  Finally, the downside of quadriceps tendon graft is early challenges regaining extension and quad weakness-both without long-lasting effects.

Surgery is performed mostly arthroscopically, with small incisions (portals) to allow access for a very small camera and small instruments. Depending on graft choice there is usually a 3-5cm open incision to harvest the graft. If I use allograft there are only 4 small incisions.  My technique utilizes cosmetically appealing incisions due to the minimally invasive technique.  I drill tunnels in your femur and tibia in an anatomic position and the graft is fixed in these tunnels with the most appropriate and cutting-edge fixation devices.  These devices do not get removed unless there are complications from them in the future. At the same time, I will address the mensicus or cartilage damage arthroscopically.

You will be placed in a knee range of motion brace, which will be given to you at your pre-operative appointment, and in most circumstances will be worn for 6 weeks. This is standard procedure but can vary from surgeon to surgeon as data and the MOON consortium tells us that bracing does not make a difference in outcome following ACL surgery. You will be full weight-bearing and range of motion as tolerated immediately after the surgery with the aid of crutches unless additional procedures were performed.

The recovery process is a long road and will require time commitment and hard-work from you-the patient.  As I said before this can be 9-12 months for some patients and 6 months for others.  We will see each other 2 weeks, 6 weeks, 3 months, 6 months, and sometimes 9-12 months to safely decide when you can return to play.  I will review your therapists notes and take guidance from them to tailor an appropriate return to play timeline for you. Your therapist will guide you through the stages of recovery and assure you are not progressing too fast as this can lead to graft failure.  They will also work with strengthening and neuromuscular training of the other knee as your are at increased risk in injuring that knee after an ACL tear. For some of our athletes, I will also consult sports mental health experts as there is a huge psychological component to trusting the knee and getting back to full sport activity.

In conclusion,  I hope this information helps as it is how I have shaped my ACL practice over the past 16 years.  I tried to offer my commentary in order to answer the “what would you do” questions but with the overlying clinical guidelines offered by evidence-based literature and surgeon experience.  An ACL reconstruction is a good surgery to allow you to remain active in cutting-sport activities and everyday life and if done as anatomically as possible may slow the progression of knee arthritis-not stop it-as you get to be my age and older.  Return to sport is extremely successful and I would one honored for you to trust me to do your surgery and get you back to doing what you love.