Watch this video of Mr Mark Jackson, Consultant Orthopaedic Surgeon specialising in knee injuries discussing ACL Injuries and Reconstruction.
This video was recorded as part of the UPMC Sports Surgery Clinic public information meeting as part of its ‘Fit for life series’ focusing on ‘How to stay healthy & injury free – From youth sport to the ageing athlete’
“ACL injury and reconstruction – an overview”
Hi, my name is Mark Jackson, and this evening I am going to be talking about the Anterior Cruciate Ligament Injury and a brief overview of the reconstruction. I am an Orthopaedic Surgeon here at the UPMC Sports Surgery Clinic. I am a Knee Specialist. I see patients and their injuries from 12 and upwards. Patients come from pretty much the whole country and are referred in by their GP’s, sports therapists, physiotherapists and other surgeons.
My work is split 50% of the work I do in sports and soft tissue injuries that incorporates the anterior cruciate ligament injury. The top three pictures are with a camera in the knee, and that is just looking at cartilage type problems. The bottom right and middle pictures here are actually cruciate ligament tears. Then the other half of the work that I do is more degenerative in nature which means osteoarthritis, and this can be offering patient’s procedures half or partial knee replacements, full knee replacements as you can see in the bottom left, more complex revision, complex primary total knee replacements and other procedures.
Today we are going to cover the Anterior Cruciate Ligament Injury. This is a very big topic. It has been heavily researched over decades. It is till I guess not completely understood, but we are getting better at helping people with this injury. Ì will try to keep it simple and not too surgical. I am going to go through some of the main points, such as what is the Anterior Cruciate Ligament, how the ACL is injured, treatment options and consequences of an ACL injury.
What is the ACL? As you can see in this picture, on the right-hand side, we are looking at the right knee from the front. The anterior cruciate ligament stands here with the joint in the middle. There are actually two cruciate ligaments, cruciate meaning crossing, so the posterior ligament is tucked in behind the ACL here in the front. The other two ligaments are the ones around the sides called the collateral ligament, so the medial or in the picture it is called the Tibial Collateral Ligament, which we often call the NCL and on the outside the LCL.
These next images are from cadaver specimens; the right-hand picture is looking from the front view of a flexed left knee; we can see these two ligaments in the middle of the knee and then the ACL, which is joining the two bones together. In most individuals, there would be a region of about 3 centimetres long and about 8-10 centimetres in diameter. It is shaped a bit like a ribbon.
So what does it actually do? Well, it is an important and primary stabiliser of the knee. It protects other structures. It is like the guardian of meniscal cartilages. It is particularly important in rotation. If it’s torn, this is An ACL deficiency which leads to a lack of confidence in typical movements. It is a fairly small ligament with a big job to do. In humans, it hasn’t evolved to be put through the rigours we demand of it. If we compare it to a mountain goat, they have a much thicker and strong ligament as it has evolved.
How can the ACL be injured? Anybody can injure their cruciate ligament. There are certainly some high-risk groups. It usually occurs in a competitive environment. Frequently it is a rapid pivot movement such as a push-off, a turn, twist, awkward landings, deceleration’s and hyper-extension. Most commonly, it doesn’t involve heavy contact or collision.
The image here in the middle shows the position of the knee when it is torn, the foot flat and twisted out, the knee falls into a position that we call valgus, buckling down and in on itself and often hip is what we call abducted, taken away from the side. This skeletal image shows us it is being damaged.
What does the typical cruciate ligament injury say? Well, usually, the history is of a sensation at that ‘the knee popped’, ‘the knee buckled’ and ‘the knee went in and out of place’. Generally, there is immediate pain, and severe pain and the patient has to be helped off the pitch. Sometimes people feel like they might want to try and continue, they get to the sideline and don’t feel too bad, but then usually, they try to run again and realise this isn’t going to work out. Generally, over 24-48 hours, the knee looks quite swollen, there is pain on weight-bearing, the patient is limping and may even need crutches for a couple of weeks while things settle down. The knee than can actually start to settle and feel ok day to day; by then, the patient is advised to see advice from a physiotherapist, A&E or their GP. The initial examination can sometimes be difficult if the patient is swollen and sore. An MRI is generally indicated. Sometimes patients are told their knee is too swollen to scan or to wait until the swelling has gone down; I don’t think this is necessary; just crack on and get the scan as soon as possible.
What does it look like on a scan? The left-hand picture here shows a very clear black ribbon structure crossing the joint, joining as we saw in the picture earlier the fibia down onto the tibia. The middle picture shows a ligament that is torn. This picture on the right shows a different sequence of the MRI, so the black line, the ligament, is torn and ripped off the bone. An MRI scan is a very accurate way to indicate this injury.
How common is it? Well, it is actually quite common. It is very difficult to incidence data in Ireland the UK but referring to other big studies and academic studies around the world; we would have approximately about 4000 ACL injuries across Ireland a year. The majority are between the ages of 12 and 35. This next study is interesting looking at high school athletes in America; it gives us again an indication of how common this injury is. They looked at ten studies that accessed high school adolescent’s males and females involved in the sport such as their local clubs and in schools, not in elite sport. They found if you follow an average adolescent sporting female in a year who maybe go from their soccer season into their basketball and lacrosse season, that’s training and playing, and they accumulate an annual risk of 2.5% risk per annum of ACL injury, which is obviously quite high. This figure is higher in females than males by about 1.6%. There are reasons for that, but we won’t go into too much detail today.
There is again, a difference between looking at an adolescent amateur athlete and comparing that to somebody who is involved in very high elite sport, and actually, the relative risk of an elite premiership footballer tearing their anterior cruciate ligament is relatively low, this study looked at 28 teams of Elite European Soccer teams, relatively the risk is quite low, so the standard male elite squad would probably only get one ACL injury every couple of years, so it is quite different to an amateur teenage type individual as these individual are quiet strong and involved in injury prevention type programs.
At the clinic here, we have a registry that we put most of our ACL injuries into so that we can look at the data and follow up results. We found that the mean age, we have about 6000 individuals on that registry now, but we found a mean age of about 25. It is important to look at the red circled groups on the screen that at least a third of our individuals are actually under the age of 20. We do operate and see more males than females, but that just reflects that males are most tensely involved in sport than women generally in terms of numbers than females.
Then talking about the Mechanism of Injury, again, as we already mentioned, the ‘non-contact’ injury is far more common than contact injury, and most of these Injuries occur in competition as opposed to training. The distribution of sports in Ireland is unique compared to some other countries because of the amount of contact in field sports that are played, So about 80% of our injuries occur in a field sport, the highest number being Gaelic football, the second-highest number being soccer, followed on by rugby and hurling. The other ones are minorities such as simple accidents etc.
There is clearly a problem that exists with an ACL tear. It seems to be an issue in very young and physically active individuals with high demands who want to get back into sports. It can be quite debilitating and life-changing with the potential for long term consequences. A lot of high-risk sports in Ireland, and not everyone is the same; we do have vulnerable and differing risk groups.
Maybe you have gone and seen someone myself; an ACL is torn; what happens next? We will discuss the options. There is a responsibility to advise and give the patient a perspective on this injury. In the short term, what we are going to try and do is the knee is the restoration of confidence, return to sports and activities and no symptomatic instability. In the long term, we would need to cancel out potential problems.
There are three main stakeholders here with this injury. Primarily the first one is the patient, and they just want a few things clear in their mind, such as fixing it, when is the surgery, when will I return to normality and how long until I return to sports. Then the physiotherapist, they’re going to very important, they’re going to have to have appropriate rehabilitation pathways in place, they will have to give guidance on what’s appropriate and what’s not appropriate of the various stages of rehabilitation and guide that individual along the way onto hopefully a successful outcome. Then the surgeon clearly needs to make the diagnosis and have a good ability to be able to interpret what we see on the scan. We need to talk about what surgery might suit that individual and to have a good reliable procedure to get the best possible outcome.
The problem with an ACL that is torn is what we talked about; the knee ‘gives way’, it does not have the ability to regenerate itself like some other ligaments might, and it doesn’t have the ability really to heal, so that person usually reports a sensation of instability not necessary any pain or stiffness. The majority of patients that I see are going to want to resume their activities when we start thinking about options, particularly surgery, but some individuals don’t have sporting goals, but they still need a stable knee for their jobs such as a Garda, the military, people with construction type works, manual labours and farmers. So even if they don’t want to go back to the sport, well often they will still about wanting surgery. This video here demonstrates the instability of someone under anaesthetic just before they’re about to have their cruciate ligament surgery. This is a movement called the pivot shift. What we’re doing is trying to reproduce the motion that happens, so the knee is kind of bent and clicking you feel it gliding in and out of place. That is an indication that the knee is unstable.
So is an operation always needed? No, non-operative treatment can be reasonable to people in certain scenarios, that might be someone with low demands or somebody who is a little bit older, so for example, if I tore my cruciate ligament and I’m in my 40’s, I don’t play contact sport or football anymore, I would probably see how I went with a good rehab program first, strengthening for 3-6 months and only then I would undergo surgery if I have failed that. If I was in my 20-the 30s or teens, I would just get on and get the surgery done as soon as possible. Some individuals are not in a position where they can commit to the time out and rehabilitation; the procedure then can be safely delayed once they can commit to a bit of gym work and take on board some of the ‘do’s and don’ts’.
If you do go down the route of non-operative treatment, some studies have been done of this and have demonstrated that at five years, even with rehabilitation, at least half of the individuals have crossed over and got their ACL reconstructed, but these are very difficult studies to do as it is very difficult to get a set of thousands of sporty young people who have torn their ligament and separate them in who is getting their ligament done or who isn’t.
For the majority of young people wanting to return to sport, I would talk to them about an ACL reconstruction. The return to sports rates are good, and most individuals will get the outcome that they want. These two pictures here are arthroscopic, showing what a knee first looks like when the camera is put in, there is such a cruciate ligament on the bone, and then this is a picture of where we put the graph in so this is the ACL reconstruction. So how do we do this? We harvest something called a graph, and there are two main options that I would discuss with patients; we prominently only use this graph called the bone patella tendon-bone. We harvest a bit of tendon from the front of the knee to get a new ligament, which we can then feed into the joint. There are hamstring tendons, and we can stick together to make a construct like this that can be fed into the joint, then hopefully become a new ligament.
In a nutshell, I’m not going to get into too much detail. What we then do is clean out the old cruciate, we drill tunnels up into the bone, and that graft we have already harvested we then have to pull out and pass into the joint; what we are then hoping is that the graph takes the mole of the original ACL and heals, but this Is a slow process, and it can’t be sped up, this is a biological healing time, and even in the best-case scenario, the whole thing takes a minimum of 9-12 months to try and get the best results. That’s how long it takes a premier footballer, and that’s how long whoever is going to be out for as well. There is also a lot of hard work to do in the gym as well while all of this healing is going on. This video shows the graft being pulled out.
Our registry is pretty reassuring, and the good news is that most individuals are going to get back into playing a sport, about 85% will, and that would be in key with lots of other studies that have performed around the world. Now re-injury is an important topic as that can be devastating, not just for that individual in the short-term but also can, unfortunately, be the end for some people in terms of their sporting environment. We can do another ACL reconstruction, what’s called a revision. It’s not easy for results or going to be as good. It’s particularly a concern in our younger aged groups, there have many studies on this, and particularly this one, patients under 25 may have a secondary injury rate of at least 23%. If you look at this Australian group results, in particular men under 18 had a very high re-injury rate of 28..3%
Long term consequences are important as what we are given people is not a normal knee, the cruciate we are putting in is not a tendon, it is usually good enough, it gives a good function and outcome, but there still are potential problems down the line. This is down to arthritis. These individuals, even 20 years later, are still experiencing problems. I would have done several knee replacements in the last few months, and men generally in their 50’s may have had a cruciate ligament injury in their 20’s. These back this up; if you look at individuals’ maybe 20 years after having an ACLR and you x-ray them, you will see at least 40% are showing signs of early arthritis and about a ¼ of them are getting symptom’s. Then looking at how common it is to get knee replacements, if you look at 15 years results, about 1% of people have unfortunately already had a knee replacement against an uninjured group.
It would be ideally nice if we could prevent ACL injury. It’s never going to be zero because of the unpredictability of contact sport. There have been studies done and programs instigated that we can actually reduce the injury rate, particularly in younger athletes and female athletes up to 50%, which is clearly very significant.
So finally, just some take-home points, this is a common knee injury, third of our patients are unfortunately young under 21, we tend to offer an ACL reconstruction to these individuals who are demanding to want to get back into sports, we want to try to give them more stability and allow them to return to the sports they love and hopefully be able to reduce further damage, the majority will get the outcome done once and get back into activity. The surgery approach is individually based. There is a need from parents, GP’s, coaches and individuals to appreciate that prevention programs work, that we do underplay a little the prognostic implications of ACL tear because of the increased risk of osteoarthritis; I always tell younger individuals this can be a problem in secondary injury rates. It is a very significant injury that we do have procedures for, but then there are issues that you need to appreciate and understand. Hopefully, that wasn’t too difficult to take on board, and there are a few points that people have taken home. Thank you.
The chance they get back is good, but unfortunately, the chance of re-injury in that age group under 21 years old is quite high. There shouldn’t be any rush; they need to tick all the boxes. I can see someone is saying their child had passed all the tests here at SCC with flying colours but, there are physiological barriers that people have to go through as well if they’ve had sequential injuries at a young age.
There is going to be a risk every day; there is some things you can change and some things you can’t, such as genetics, the shape of your knee, collagen, which is what your ligaments are made of its not unusual to operate on twins or brother and sisters. If it was my kids, I would let them return if they were able to, but if they kept getting re-injured, then you would need to have the talk if it’s worth carrying on in that sport.
That’s often one of the very first questions people ask; generally, it is important for people to understand that it’s not time-dependent. There is a biological healing phase, which everyone has to go through. It doesn’t matter if you’re a premier footballer or not. There is a ligament healing time, but after that, you shouldn’t be time-dependent; in the past, it used to be, you could go back to play after six months, but we have moved away from that because of the realisation that most people are nowhere near ready at six months.
I tend to recommend 9-12 months, a minimum of 9 months. At nine months, there is an assessment from my perspective on how does the knee look, how the knee feels, swelling, pain and movement good. There is also a test that we often arrange for individuals to see how symmetrical they are between legs, seeing how they are for their body weight, strength scores, and also getting them to do simple tests like landing and hopping tests. Very few people are actually ready at nine months, there shouldn’t be a rush in my opinion, particularly in a younger individual they have everything to lose and nothing to gain, trying to go back at nine months instead of 12-18 months. If that’s what a premier football needs, that’s what everyone needs.