Anterior Cruciate Ligament

Injury and Reconstruction

You have torn your anterior cruciate ligament. This ligament cannot heal adequately on its own. It is the single most important structure in maintaining stability in the knee for twisting and jumping activities. Now what?

Consequences of an ACL Injury

Initially (following the injury):

Usually there is a lot of pain for the first few minutes, although some people have minimal pain and are keen to play on. Those who do usually find that the knee is not safe to change direction or to land on that foot. The knee usually swells within a few hours; sometimes quite rapidly, but sometimes overnight. Crutches may be required, and often the knee is too sore to straighten right out. Once the knee settles, it usually feels fine again; that is until you try to get back to sport involving landing or twisting.

ACL Treatment Options

Limitation of Activity

Many people can get by without their anterior cruciate ligament if they avoid twisting and/or propping activities, and give up contact sport. Tennis, squash and skiing etc. are moderately stressful but some people manage these sports quite well. Cycling and swimming are recommended to keep fit and active. Running in a straight line is also usually fine.

Rehabilitation

For those for whom it is likely to be safe to live without an ACL, or for whom any surgery has to be delayed for some time, a physiotherapy supervised exercise program is recommended to strengthen and co-ordinate the hamstring muscles. These muscles may prevent the knee from giving way if the knack is learned and maintained. This program is best supervised by a physiotherapist who will test the knee function at the end of the program. If you pass, you may gradually try returning to non-contact sport. You will be shown techniques in landing and side-stepping that may reduce the risk of the knee giving way. There is no guarantee that this will prevent tearing the cartilages, due to slippage episodes, or the subsequent degeneration of the knee, even in the absence of real giving way episodes. And, of course, the maintenance program has to be kept up. Once you forget, that’s when the instability is likely to catch you unawares.

Bracing and/or Strapping

This is a somewhat uncomfortable way of giving the unstable knee some support and a feeling of security. A simple knee support may feel OK, but a properly designed ACL brace would be required for sport that might provoke slippage or instability feelings. A correct, specialised taping technique can also keep the knee pretty stable, at the cost of slightly restricting full straightening. (I could show you how to do that if you really wanted to try that option. Very few people know the trick.) Both taping and bracing are really just temporary solutions (recommended if surgery is not an option for you at that time) to reduce the risks involved in trying to return to sports activity. In rare circumstances, however, it may be the best option.

Anterior Cruciate Reconstruction Surgery

This is recommended if the knee remains insecure after rehabilitation, and/or a limitation of sporting activity is unacceptable. For most people intent on returning to higher risk sports such as football or netball, or other sports requiring jumping and twisting etc., it is best to proceed directly to surgery before further damage is done, and to allow the earliest safe return to sport.  The odds of a successful return to sport are so good that it is not taking the risk of trying to return without an intact ACL.

Advances in ACL reconstruction techniques and reliability over the years have made this operation much more acceptable to athletes, and to anyone who simply wants a knee they don’t have to worry about, despite the long period of rehab that is required.

On the other hand surgery does not guarantee a completely satisfactory knee. It will almost certainly improve knee stability, and success, in terms of the ability to return to vigorous sport, is achieved approximately 90% of the time. (Of course not everybody who could, does end up returning to their sport, as some would rather not take the chance of another injury of any sort.) Reasons why the knee may not be as good as hoped include the possibility some stiffness and clicking, or some tenderness and occasional aching in the stable reconstructed knee, especially if there is already other damage within the joint. A very small percentage end up with stiffness or too much scar tissue in the knee, or, at the other end of the spectrum, a knee that remains loose.

Meniscus Repair

You may well have a torn cartilage already, but this may be repairable. If that is the case, it is desirable for the long term well-being of your knee to have the cartilage repaired, and for that repair to be protected by having the anterior cruciate reconstructed, and the sooner the better. If you are undecided about having a reconstruction, I would advise getting an MRI to check on the state of the cartilages. If there is a repairable meniscus tear, that should influence the decision in favour of getting on with the reconstruction.

Final Word

Please do not persevere with a knee which is shifting or giving way as you will cause further damage to the knee. Get a referral to a knee surgeon sooner rather than later, and work out the best solution for your particular circumstances.

ACL Reconstruction

The decision to reconstruct the cruciate ligament is made when it is expected that future instability cannot be controlled by physiotherapy or a limitation of sport, or of course when that is not an acceptable option, and sometimes when there is a meniscus which needs to be repaired, to protect that repair.

The choice of graft depends a lot on your surgeon's preference. There are arguments for both hamstring tendons, and a graft from the middle of the patella tendon (from the knee-cap to the top of the shin) including a block of bone at each end (a bone-tendon-bone graft). My preference is for hamstrings, for the following reasons: A lot of people don't ever like kneeling on their knee after taking part of the patella tendon; The recovery in the first few weeks is a lot easier after a hamstring tendon graft; and the long term results suggest less arthritis with hamstrings than patella tendon grafts. Against this is the possible mild persisting weakness or tightness in the hamstrings. This is not discernible to the vast majority of athletes, but could possibly be of concern to an elite sprinter.

It should be noted, however, that there is also a failure rate of biological reconstructions of maybe about 1% per annum due to re-injury, even with the best surgeons' results. The failure rate among AFL elite footballers, for example, is a good deal higher.

Synthetic Ligaments/Lars Ligament - Why Not

From time to time it seems, there is a new fad phase in favour of some "revolutionary" new artificial ligament. The last was only a few years ago when those who hadn’t lived through boom and bust of the synthetic ligament era in the 90’s became enthused by a device that purported to solve all those problems. The truth is that all artificial ligaments will inevitably suffer fatigue failure sooner or later. That doesn't mean that all the old synthetic ligaments failed. For some people who are low demand, the results are that a small percentage were still stable even after 15 to 20 years. But basically the only ligament that can maintain itself against the stresses of normal, and especially high demand, usage is a living ligament of your own biological tissue. So that is still the best choice, unless there is an extraordinarily good reason to go for this new artificial ligament.

There are some special circumstances when a synthetic graft might be a good idea. For an AFL footballer, who is possibly nearing the end of his career, if he had to spend 12 months out of the game after a biological graft, and then potentially struggle to regain sufficient form to demand a regular spot in the team, the chances of getting back to the top level, and high earning capacity, aren't all that good. For guys in that position, it could be a good career move to have a synthetic ligament as a short term solution, even if it does need to be redone in 2-3 years or so. The same thing goes for someone who gets injured only 3-6 months before the major event of their life, like the Olympics, for example. For the other 99.9% of us, there is no real advantage in getting back to normal day to day activity any earlier however. It only takes about 4 weeks even after a biological reconstruction. At this stage almost no surgeon would offer a synthetic graft except in the most extenuating of circumstances.

Your Surgery

The following description is how I do it. The operation will be performed under general anaesthesia (with very occasional exceptions). There will be one small incision to harvest the graft and pass it through a drill hole into the knee. The rest of the procedure is done arthroscopically requiring two 5mm puncture incisions. The graft is passed through to the attachment site on the tibia, then through the joint, and through a drill hole in the femur. A small titanium screw are used to fix the graft within each tunnel to create the new ligament. They do not usually need to be removed later, as titanium is very biocompatible, and the screws are buried within the bone. When you wake up there will be some discomfort for which you will be given medication. Usually, you will be able to go home on the same day. You will probably need crutches for just a few days after the surgery.

Complications

Please Note.

Before the surgery you must advise your surgeon of any health problems or medication you are on, eg. any medication containing Aspirin or Warfarin (to thin the blood) or arthritis tablets (Feldene, Voltaren, Brufen, Indocid,Orudis etc.). It may be necessary to temporarily cease taking some medications prior to your surgery to prevent bleeding complications.

 Before the surgery you must advise your surgeon of any health problems or medication you are on, eg. any medication containing Aspirin or Warfarin (to thin the blood) or arthritis tablets (Feldene, Voltaren, Brufen, Indocid, Orudis etc.). It may be necessary to temporarily cease taking such medications (especially warfarin) prior to your surgery to prevent bleeding complications. Complications (anaesthetic, medical and surgical) can occur after any surgery. I am pleased to advise that we have a very low complication rate by world and Australian standards, which we constantly monitor, and great care is taken to minimise such problems. We regularly audit our results, complications and patient satisfaction to improve and maintain the highest standard of care. Possible problems include infection (antibiotics are given at the time of surgery to present this, and the graft is soaked in an antibiotic solution), bleeding, swelling, stiffness and venous thrombosis (blood clots). Stiffness and excessive scar tissue formation in the knee is a particular problem that sometimes occurs after a cruciate ligament reconstruction. This is minimised by doing the operation arthroscopically, early movement after surgery, and use of physiotherapy. Uncommonly, it may become a cause of ongoing problems. Very occasionally the graft may fail to heal strongly, or may be re-injured, so that some looseness or even instability could recur. If any of these problems occur they would usually respond to further appropriate treatment as required. It should also be emphasised that at the time of arthroscopy additional damage may be found inside your knee. I would treat those problems in the best possible way at the same time (eg. repair of cartilage), and advise you if such damage is likely to have a negative impact on your knee in the short or long term.

ACL Reconstruction Rehabilitation

Before you leave hospital, the physiotherapist will visit you to show you your initial exercise program. Continue to do the light exercises as detailed in the physiotherapy handout you will be given, but also make sure that the swelling is progressively settling down. At 2 weeks post-operation you will see me (or your local doctor if you live far away from the city) and physiotherapist for a check-up. The suture usually dissolves and does not need to be removed.

After 2 weeks, you could be comfortable and mobile enough to get back to work, if you do mainly desk work. By 4 weeks, your knee should be settling well enough that you could get back to work on your feet most of the day, although there would still be some swelling in the knee, especially by the end of the day. Individuals vary a lot, so these estimates are just a rough guide. Some will do better. Some not so well.

The aim during this first 6 weeks is simply to let the graft heal, and get reasonable movement and muscle control of your leg. Strengthening rehab is not required, and could harm the graft as it goes through its weak phase in the early stages of healing at around 3 weeks. The graft starts out stronger than the original ligament, but as it gains a blood supply and starts to heal and remodel, it can drop to only about 20% of its initial strength, so it is important not to push the knee at this very early stage. This is a critical time, especially for teenagers who, statistically, have a higher early failure rate. Maybe that is because the knee starts to feel so good that they forget that they still need to protect it and take care of it.

Also, for those who have had the hamstring tendons used as the graft, stretching exercises are important, but despite that, it is not unusual to pull your hamstrings at some time in the first 6 weeks. This is painful for a day or two, but by persevering with some ice and stretching exercises, it quickly settles, and goes on to recover well.

The next review is at 6 weeks post-operation, and I would want to check your progress personally at that time. You should then be ready to move on with a controlled strengthening and stretching rehab program. Leg extension exercises should be avoided as they put excessive stress on the graft which is still quite weak. Your physio will show a program of what are called "Closed Kinetic Chain Quads Exercises" which means that all the resistance when doing your quads exercises has to go through the sole of the foot. By 12 weeks, you should be able to start jogging, and from there, build up running and agility training, as well as unlimited gym work.

By 6 months you should have regained full strength and movement as well as confidence to able to get back to playing contact sport, although it usually takes another 3 months or so to regain form. You should have final surgical and physio reviews before returning to contact sport to check that all is well and that you are ready. In particular, it is most important to learn correct landing technique, to the point that it becomes second nature.

Periodic physiotherapy will be required up to the final assessment at 6 – 8 months. It is important that in the first 3 to 4 months the rehabilitation is controlled and along the specific guidelines set out by me and the physiotherapists. Full graft strength takes up to 18 months but the graft is strong enough for return to sport after 6 months, or about 12 months for the high intensity of top level AFL for example, where it is not good enough to be strong and safe, but it is also necessary to have regained top form to earn a spot in the team.

It is also important to remember, that although a successful ACL reconstruction restores the knee back to about normal, it does not make the knee immune to injury. The statistics are that you have about a 5% chance of tearing the ACL in one or other knee at some stage in the future, if you continue in high level sport. This risk can be minimised by always doing an agility warm-up routine before every training and game. Most sports now have recommended programs on the websites.