Why do we care so much about the ACL?
The Anterior Cruciate Ligament (ACL) is extremely well known in the sports medicine world. Due to the impact these injuries have on the athletes as well as their high incidence in pivoting sports, the ACL has been and continues to be heavily researched. Despite all the research, the best way to manage these injuries is still being debated and investigated through clinical trials. Anyone who plays a pivoting sport, whether it involves contact or not understands an ACL tear is the last thing they would want to suffer. Why is this the case though? Well, If I give my opinion based off when I was a kid growing up playing Australian rules football, an ACL tear diagnosis indicated 12 months away from sport following surgery. Even a successful return to sport, there would always be the fears of will I be able to perform like I did previously, and if I go back to sport would I just tear it again? Watching the professionals as a kid, you would be devastated when a player from your team received that diagnosis as you knew you would not see them play for a full season! Why do we care so much about the ACL? It is simple, they are extremely prevalent with a rising incidence despite new research improving our understanding on these injuries. They are significant injuries that have a serious impact on the physical, psychological and social health of the athletes.
Australia has the highest incidence of ACL injuries in the whole world, with over 10,000 a year (Moses et al., 2012). This number unfortunately is rising every year, due to many reasons. The primary reason is that we have more people playing sport than we did ever, with the rapid growth in female sports. It is reasonably well known that females are more likely to suffer an ACL injury compared to their male peers. This is still a growing area of research, however it is important to note that currently there is no conclusive correlation between ACL injury and the menstrual cycle (Sutton & Bullock, 2013). This blog will not focus too much into the detail of why females are more likely to suffer an ACL injury, however an important fact is that females are 2-8 times the injury risk of males.
Why is the ACL so important? The ACL can be seen as the sensory organ of the knee, which is why the whole biomechanical system of the lower limb can be affected post injury. The primary role of the ACL is to prevent the anterior translation of the tibia (shin) on the femur (thigh). It also plays a secondary role in providing rotational and lateral movement stability. The ACL has two distinct fibre bundles, the anteromedial and the posterolateral. The anteromedial bundle is considered the main bundle and its role is to prevent the anterior translation of the tibia on the femur. Whilst the posterolateral plays a role in preventing rotational instability. It is a ligament that is extremely important in stability of the knee and therefore the lower limb.
The majority of ACL injuries are due to a non-contact injury mechanism and in the recreational change of direction athletes. Non-contact ACL injuries account for 70-80% of all ACL injuries. In other words, those who injure their ACL do it without colliding with another player 70-80% of the time. The typical mechanism of an ACL injury involves an athlete changing direction with a flexed knee that internally rotates at the hip, creating a valgus force at the knee joint as the cutting (planted foot) lands away from the body in external rotation. The trunk of the athlete often will be positioned over the cutting foot, creating an axial force through the knee. This combined axial valgus force is the resultant force that can lead to an ACL tear. If the extreme majority of ACL injuries are non-contract mechanisms, then could we prevent many of them occurring? You can never completely prevent injuries, however you certainly can mitigate the risk of injury considerably. How this is done is through structured strength & conditioning with a competent practitioner/coach who understands these injuries and the science of programming. This is a service we offer at The Reform Lab Osteopathy, a proactive approach to injury through strength and conditioning.
Another major issue with ACL injuries is the high likelihood of suffering damage to surrounding structures during the injury mechanism. Injury to other structures in the knee certainly can complicate the rehabilitation process and overall treatment decision to get surgery or not. Often if there are injuries to other structures like the meniscus, medial collateral ligament (MCL), lateral collateral ligament (LCL), posterior cruciate ligament (PCL), fracture to surrounding bones, then these injuries are usually referred on for surgery. ACL injuries more commonly occur in younger individuals that are playing these pivoting sports as we have already discussed. The burden of these devastating injuries leads to future concerns with knee health, as these young individuals often will experience early onset osteoarthritis. This can be extremely concerning for many young athletes and their parents, potentially long-term knee health complications after a sudden split-second injury in the sport they passionately play.
Complications after an ACL injury and the fear of re-injury is a major reason why many individuals (including very young athletes) never participate in sport again! This fact alone is a major reason why we care so much about ACL injuries. The athletes sport is their passion, their social connection, and their escape from daily stressors. For them not to participate again due to fear of re-injury can really have a massive impact on their psychological wellbeing. The psychological effects of an ACL injury is the biggest reason why I care so much about ACL injuries. With great strength & conditioning exercise rehabilitation, it is an absolute delight seeing the confidence return in athletes when I work with them.
How common are re-injuries after an ACL reconstruction? Unfortunately, up to 30% of young individuals who received an ACL reconstruction via surgery, suffered a second ACL rupture within the first few years after surgery (Paterno et al., 2014). Females in particular were at an increased risk of suffering an ACL injury to the opposite side! Younger athletes are of concern, with those aged 20 or younger who underwent an ACL reconstruction at a significantly higher risk of both graft rupture, and the opposite ACL (other knee) being injured. Why are young athletes at a higher risk of re-injury? It could be a number of reasons; one being they are not objectively tested with sports science equipment prior to returning to sport. Therefore, they are being cleared to return even though they are significantly load compromised in their knee. This leads me onto why I care so much about ACL injuries.
Why do I care so much about ACL injuries? Obviously, all the above. However, I experienced firsthand just how bad the management of these injuries is in Australia and the world. I suffered an ACL rupture and multi-directional lateral meniscus tear, requiring an ACL reconstruction. I am obviously qualified as a passionate sports osteopath (was not an S&C coach at this stage). However, despite my long and intense university studies, the ACL injury was not heavily discussed or taught the way it needs to be. After I had surgery, ACL injuries and the management of them, became my biggest passion and area of interest. Through the orthopaedic outpatient clinic, I popped in to have physiotherapy. The first few weeks after an ACL reconstruction are hell by the way, I was in a lot of pain and really excited to see someone for help. I actually remember feeling sorry for the physiotherapists, as I could see they had a very poor understanding on ACL management. That is not really their fault, it is the universities that do not have the appropriate individuals teaching the right content. From that appointment, I decided I would just manage it on my own without help. The more I learnt, the more I was very frustrated at the current management of these injuries.
ACL injuries should not ever be managed by a health care provider who is not competent in ACL management or exercise rehabilitation! I am very strong on this, as I have seen through my career many being told they can return to sport as the surgeon said they were structurally stable. Or the allied health professional gave them clearance after just massaging them for 6 plus months. If manual therapy is all your health professional does, then certainly go get another who is educated and cares about you getting better, this applies to all sports injuries! If general practitioners and surgeons started referring to practitioners that are competent with all stages of rehabilitation (early to late/return to sport and performance), then ACL patients will be getting high value care! This would significantly reduce the re-injuries that are a massive burden in Australia and the world. It will also lead to better performance when they return to sport and increase the athletes confidence to return to sport.
I say to all my patients that have a sports related injury. You should look at this as an opportunity to be better than you previously were prior to the injury. At The Reform Lab Osteopathy, we work inside the elite facility of Project Reform and have sports science testing equipment that highlights your strengths and areas of improvement. The testing equipment I use is mandatory for all ACL injured athletes looking to return to sport. There are specific criteria that the athlete must hit, before I give them the tick of approval to return to sport. A massive limiting factor in ACL rehabilitation are the facilities a practitioner has access to. If you are completing ACL rehabilitation, you should make sure your practitioner has access to a range of gym equipment. Fundamentally, you need to ensure they have access to official testing equipment like we do here at The Reform Lab Osteopathy.
Since opening up The Reform Lab, it has been an absolute pleasure to witness athletes return to sport and perform at a high level post ACL rehabilitation without any physical or mental barriers to performance. If you are wanting to take your ACL rehabilitation to the next level and get the high level care that is needed, please reach out. I would love to help!
References
Moses, B., Orchard, J., & Orchard, J. (2012). Systematic review: Annual incidence of ACL injury and surgery in various populations. Research in sports medicine (Print), 20(3-4), 157–179. https://doi.org/10.1080/15438627.2012.680633
Sutton, K. M., & Bullock, J. M. (2013). Anterior cruciate ligament rupture: differences between males and females. The Journal of the American Academy of Orthopaedic Surgeons, 21(1), 41–50. https://doi.org/10.5435/JAAOS-21-01-41
Renstrom, P., Ljungqvist, A., Arendt, E., Beynnon, B., Fukubayashi, T., Garrett, W., Georgoulis, T., Hewett, T. E., Johnson, R., Krosshaug, T., Mandelbaum, B., Micheli, L., Myklebust, G., Roos, E., Roos, H., Schamasch, P., Shultz, S., Werner, S., Wojtys, E., & Engebretsen, L. (2008). Non-contact ACL injuries in female athletes: an International Olympic Committee current concepts statement. British journal of sports medicine, 42(6), 394–412. https://doi.org/10.1136/bjsm.2008.048934
Domnick, C., Raschke, M. J., & Herbort, M. (2016). Biomechanics of the anterior cruciate ligament: Physiology, rupture and reconstruction techniques. World journal of orthopedics, 7(2), 82–93. https://doi.org/10.5312/wjo.v7.i2.82