In the last 5 years in the premiership there has be an over 50% increase in the occurrence of devastating ACL injuries. Not the once career ending injury it once was with the advances in surgical repair and reconstruction, but still a season ending event with often very significant consequences both for the team and for players in the short and long terms. Even the best orthopaedic surgeon in England or even the best orthopaedic surgeon in the World don’t completely understand why!
There have been many studies done by the best knee surgeons to try and understand better why this seems to be and injury on the increase. There are many theories thrown around the changing rooms of clubs across the country. Some of them include the artificial surfaces players are now playing on, the boots and studs they use, the intensity of the fixtures and the demand on players, the warm up regimes and the overall fitness of players. The truth is we don’t currently know, and like most problems in life it is not just one factor but a combination.
Let’s look at each of the theories in turn, but first we need to understand what the ACL is and what its role is and then we can begin to understand how and why it gets injured.
The anterior cruciate ligament is a small structure that crosses the knee between the femur (thigh bone) with the tibia (shin bone). It is approximately 32mm in length and 8mm in diameter. Its main role is to resist the pivoting movement of the tibia on the femur when a player is changing direction. It is a very strong structure and can resist forces up to 250kgs. If the ACL becomes over stressed and torn it is not something that can repair itself and especially in footballers leads to significant problems and damage to other important structures within the knee. Pivoting and cutting maneuvers are fundamental to football and without a functioning ACL most are unable to return to their original level of play without surgery.
So now understanding the structure of the ligament and its role in the knee, how do the different theories hold up to scrutiny?
- New Playing Surfaces?
Many of the premiership clubs now use artificial turf as a surface for playing football. There are limited studies looking at the incidence of ACL injury in relation to the playing surface, however in the US where American Football is almost universally played on artificial turf there is a new study to show that these surfaces have a nearly 40% increased rate of ACL injury over traditional playing surfaces. These surfaces are unforgiving and very stable and predictable. This is part of their problem! By providing too much grip and no give or slide, players feet can often be fixed in a certain position and the change of direction movements they have, happen at their knee joints and stress the ACL beyond its capacity causing it to rupture. These surfaces are going to become more common and something that need to be investigated further. This leads on to the next most discussed possible reason for the increase in injury…the boots!
- The Boots?
The design and development of football boots and studs is something that has accelerated in the last few years. With the advertising revenues available from elite level football and being the brand of boots on the best players feet is an important goal for sports companies across the globe. In order to compete for this coveted position, millions of pounds have been invested in the design and research of football boots. There is no high-level research available to look at the types of studs and the correlation with ACL injury in particular. However, there are some eagle eye amateurs out there trying to look for links. One football fan site has correlated all the players over the past 24 months who have sustained an ACL injury and looked at what boots they wear, and if there are any trends. Interestingly there became a clear pattern with one manufactures boot type. This is not scientific or robust research and may simply be a coincidence, however it is an interesting observation and something if I was the manufacturer would take heed of and definitely warrants careful scrutiny. The current blade designs provide exceptional stability and may even provide too much, fixing the players foot rigidly in the playing surface allowing their body to pivot over their knee injuring their ACL. This maybe compounded by the hard-artificial surface discussed above.
- Demands and Fatigue?
The ACL is not a seatbelt for the knee, simply restraining the knee when we push things too far. It is a small brain filled with sensors that feedback where the knee is at any given moment in time. It works in combination with the other structures in and around the knee. The hamstring muscles at the back of the thigh and the powerful quads muscles at the front of the knee also help support and stop the knee moving beyond what it is capable of before injury. If players are fatigued and tired with busy match schedules it has been shown in studies that the normal protective feedback from the supporting muscles fails and the ACL can be over loaded in an abnormal fashion, putting players at risk of rupture. When this point is, is very player dependent and everyone’s thresholds are different. Understanding each player and their limitations is vitally important as well as making sure their overall level of fitness is as high as it can be giving them as much reserve as possible.
What can we do before it happens?
Further research is required to clarify the issue above, however FIFA has already instigated a plan to try and reduce the risk to players at all levels of the game through their 11+ Injury Prevention Program. This is an evidence based program developed and studied by the FIFA Medical Assessment and Research Centre (F-MARC). This was developed in 2006 as a complete warm up program to help prevent injury in footballers. The aim being to make sure players recruit and use their muscles correctly and in a balanced fashion to help support and prevent injury. Studies have shown that implementing this program can reduce the rate of injury, including the risk of ACL.
What can we do if it does happen!
If you are in the unfortunate position of sustaining an ACL injury and you are a high-level athlete, like mentioned at the beginning of this article it is no longer the career ending injury it once was. Advances in arthroscopic surgery (keyhole) means that we can reconstruct the ligament using your own tissue to give your knee that feedback and stability it needs. The cutting edge of this surgery now includes striving to reconstruct the ACL back to the exact position that the original one once was in using minimally invasive techniques that reduce the amount of bone that needs removed and hardware that needs implanted, unlike traditional ACL reconstruction surgery (Arthrex All Inside, Arthrex, Ltd, Naples Florida). Research includes producing custom made 3D printed guides (Frame, M. (2017). Custom Anatomical 3d-Printed Patient-Specific Acl Femoral Tunnel Guide From Mri: A Proof Of Concept Study. Bone Joint J, 99-B(SUPP 9), 51. Accessed September 12, 2017. Retrieved from the best knee surgeon in hampshire http://bjjprocs.boneandjoint.org.uk/content/99-B/SUPP_9/51. the best knee surgeon in england) from scans of the uninjured knee to help place the new ACL in position specific to each individual patient. The ability to treat patients early and rather than reconstruct their ligament, we can now aim to repair their original ACL and support it with an internal brace (Arthrex Internal Brace ACL repair, Arthrex, Ltd. Naples Florida) until it is healed allowing then to get back to their original elite level even quicker.