25 Questions on (anterior) cruciate ligaments

1) What do you mean by cruciate ligament?
To explain this term we need some basic anatomy. The knee consists of three bones. First we have the thighbone (os femur) and the shinbone (os tibia) and also the kneecap (patella). Apart from that, we also have two menisci. These are cartilaginous disks that make everything fit nicely and on top of that provide some shock absorption while walking. The patella and the menisci will not be considered in this article.
The thighbone and shinbone should not be allowed to be pulled apart but should remain put together when the knee is stretched as well as when it is bent. On both sides of the knee sit ligaments that hold the bones together and provide sideway stability. On the inside of the knee are two cruciate ligaments that take care of the lower leg not being flicked forward or backward. The anterior cruciate ligament prevents the shinbone from moving too far forward and the posteriate cruciate ligament does the same for backward movements. Besides that they limit the amount of twisting possible in the knee.
For the sake of completeness. This entire knee, except for the posterior ligament, is comprised within one joint capsule.

2) Why are they called cruciate ligaments?
They are called like this because they cross each other in the knee. For those interested: the anterior cruciate ligament comes from the lateral condyle of the femur and goes to the anterior intercondylar area. The posterior cruciate ligament comes from the medial condyle of the femur and goes to the posterior intercondylar area.

3) Which of the cruciate ligaments causes most trouble?
The anterior cruciate ligament does. Injuries on the posterior cruciate ligament are quite rare. It does happen that football keepers get kicked on the shinbone of the standing leg. His lower leg will shoot backwards resulting in rupture of the posterior cruciate ligament.

4) Ok, let's get on with that anterior cruciate ligament then. What could happen to it?
The ligament could overstretch, rupture partly and torn completely.

5) How could that happen?
Unfortunately, the ways to that are plenty. Most common is when someone attempts a shot with the inside of the foot (so the knee will be slightly rotated and there will be tension in the cruciate ligament) and the opponent blocks it. Another favourite is falling in skiing while the straps stay connected or stick behind a slalom gate. This injury could also happen in any sport with many twisting moments, cap movements, fast slowing down and landings (leap down).

6) Are there any groups of risk you could mention?
Yes, unfortunately so. This group makes up about 50% of society. It has been concluded that women, at the same amount of exercise, suffer much greater risk of anterior cruciate ligament injuries than men. In soccer factor 2 and in basketball as much as 4 times as high a risk, compared to men.

7) How is that so?
It is probably a combination of factors. First, there are some anatomic differences between men and women. For example, the space for the cruciate ligaments in the knee is smaller. Because of that they get stuck more easily and get damaged sooner. The broader pelvis of women makes their legs have a more sideward angle (x-legs). Next to that, the hamstrings that help the cruciate ligament do its job are less strong. The hormone of oestrogen is also not very convenient. The build-up of ligaments is slower because of this and periodically they are weaker, too. In conclusion it adds that women tend to start doing sports later so their general condition, strength and motorial skills are less developed. This last bit will probably stop playing a role by the next few years.

8) This doesn't make me feel glad at all. But how do you know you have an anterior cruciate ligament injury?
It depends on the seriousness of the situation.

9) So let's start with overstretching?
That would be grade 1. You would probably know you stumbled. The next day your knee might be a bit swollen but it is still stable. It has to be said that the knee can remain painful for a longer period. If you take some care it will heal by itself.

10) So what would be grade two?
In this case the anterior cruciate ligament is partly torn. The knee will swell and could become instable.

11) I fear the worst for grade 3?
Indeed. In this case the anterior cruciate ligament is torn completely and the knee will immediately (within hours) swell and it feels instable. In about 80% of the injuries the sportsman heard something snap. If you are really unlucky the meniscus and medial ligament are also damaged.

12) What should one do if he or she suspects something?
You cannot do much. Good cooling and put the leg up is about it. Pressure bandages could be useful but also painful. Besides, you would have to remove it frequently to be able to cool it. If you suspect a grade 2 or 3 or when in doubt always go straight to the doctor or first aid to get a good diagnosis.

13) How will they set a diagnose?
A first indication is the speed with which the knee has swollen. If it happened in only a few hours there is often blood inside the knee and further research will be too painful. By removing the blood partly pressure will decline and further research should be possible.
If you are lying on your back, with bent knee, the doctor usually will be unable to move your lower leg relative to the upper leg. If he can, you are surely suffering from an anterior cruciate ligament injury. In hospital they would usually do x-ray research to exclude possible bone fractures. Diagnostic keyhole surgery is also practised as a rule.

14) Great. Now we know what it is, how to get it and how it is diagnosed. How do you get rid of it?
That depends on the severeness and on the first day that will be hard to guess. In the case of grade 1 and 2, a good rest and physiotherapy will suffice. The worst pains will disappear in about two weeks. Full recovery will take more time.

15) What will the physiotherapist do?
He will help the knee to be able to bend again and make you practice in order to regain strength in the thighbone. Especially the muscles on the back (the hamstrings) will have to be strengthened to partly take over functions of the cruciate ligament (muscle corset). To ensure muscle balance, the front (quadriceps) will also be trained.

16) What will happen to people suffering from anterior cruciate ligament injuries?
With 1/3 of the patients, there are no complaints following the acute phase. They go without any problem from bedroom to car, by elevator to the sixth floor and they fully rejoin their billiards competitions. 1/3 will experience great difficulties in daily life. They will be considered for a new anterior cruciate ligament. All the other people only have problems during extreme exercise. Normally they do not have complaints. They quit their sports, look for support in knee braces or choose to have a surgery after all.

17) Couldn't such a knee brace be used precautionary?
No, absolutely not. The knee is an incredibly complex capsule in which you cannot limit one movement without constraining others. In rehabilitation phase, a brace could help, but only there where a specialist has prescribed it.

18) How do I imagine a surgery?
The operation can only take place when the body is mature and will be done in partial or complete narcosis. It is not a small thing and takes about one or two hours. Because we have not gotten any spare tendons on birth, a new anterior cruciate ligament is made of the patella tendon (kneecap tendon). The middle part of the tendon, including some bone, will be cut away. During a keyhole surgery, one part will be screwed to the thighbone and one part will be screwed to the shinbone. Right at the spot where the old ligament was. It is also common to use part of the tendon of the hamstring.

19) Is the operation very painful?
Commonly speaking, the pain, also later on, is not so bad. In case of need, painkilling could be considered for the first few days.

20) Could you start doing sports again right after the surgery?
No, you would not even think about it. The first week is to try to bend the knee up to 90 degrees and you will learn to walk using crutches. Your toes can only softly tap the ground. In the following weeks everything is done to decrease the swelling. By roughly four weeks you should be able to walk without crutches and you can start cycling again and drive a car. After six weeks the tendon will be fully attached to the bone. Only after six months will the transplanted tendon be transformed into living tendon tissue.

21) Do you have to stay home for six months?
No, after 6 weeks you can start doing light work and after 12 weeks you can start doing heavy work.

22) When can you do normal training?
Depending on how it all goes and in consult with your physiotherapist, jogging on even terrain can be started after eight weeks. At twelve weeks you could start to do twisting exercises. It takes six to eight months before your knee is fully functional again and contact sports are safe.

23) Does a new cruciate ligament have the same strength as the old one?
No, the new cruciate ligament can only reach to about 80% of the old strength. It will thus remain a weak spot.

24) What is a general indication that you are up to doing sports again?
In any case, you should first consult your physiotherapist. The sportsman should have no pain, the muscle strength should be on the level before the injury and the agility of the knee should be restored completely.

25) Are there any precautionary measurements to be taken?
Yes, there are several possibilities but absolute prevention is impossible. Examples are:
Good material (connections etc.)
Good shoes for the floor on which is played
Good technique and coordination training
Power training of the upper legs and especially the hamstrings
Warming up with coordination exercises
Fair play and a capable competition leader

And in conclusion: Listen to your body, it is your best advisor.

Live Long and Prosper!