• Anterior Cruciate Ligament Injuries (ACL)

    Per head of the population, more Anterior Cruciate Ligament Injuries (ACL) occur in Men than in Women, although per head of the sporting population there are more ACL injuries in women.

  • Ligaments attach bone to bone and generally help to stabilise and protect joints.

    The ACL is a very important ligament running between your tibia (shin bone) and your Femur (thigh bone) .This ligaments helps to ‘centre’ the knee and damage to it frequently results in marked instability, with the person complaining of serious giving way and mistrust of the knee’s ability to function properly.

    This is especially prevalent in sports or everyday activities which involve twisting and turning or sometimes rapid acceleration or deceleration.

    Damage to the ACL occurs for many reasons but for the purposes of classification can be broadly placed into three groups.

    Type I: Direct Contact, where a direct force is applied to the knee, for example where a football player’s knee is forcefully struck by another player or a player falls and strikes their knee on a goalpost.

    Type II: Indirect contact, where an external force is applied but not directly to the injured knee. For example a player is struck and knocked off balance by an opponent in the area above the knee (i.e. the thigh or the torso). The following awkwardness of movement leads to an injury to the ACL, without direct contact to the knee.

    Type III: Noncontact, where forces applied to the knee at the time of injury, resulted from a person’s own movement and did not involve contact with another person or object. The classical way of injuring a knee in this way involves a flexed (bent) knee, when the foot is contacting the ground and the lower leg goes outwards/laterally (anatomically it is said to be placed in a valgus position). If anyone remembers Michael Owen’s injury in the World Cup they may be able to picture this and it is recommended that if you wish to see this exact type of mechanism, have a look at footage of his unfortunate injury).

    Can we have an influence on these types of injury?

    It is thought that we can certainly have an influence on the non-contact injuries mentioned above, in the light of up to date research and Physiotherapists should be working more to try and prevent these types of injuries from occurring.

    It is also important that sports coaches and physical education teachers try to seek the opinion of Physiotherapists interested in knee injuries and prevention of them.

    There is strong research to show that Physiotherapists can work with athletes or just everyday participants in sport, including children, to put into place programmes that will strongly reduce the risk of ACL injuries from occurring.

    There is little evidence to show that these same programmes will particularly make a difference to performance, although a non-injured participant will of course perform better than an injured participant, who may not be able to play at all!

    Preventative programmes are a way of reducing the chances of injury to the ACL but other factors are also worth considering.

    For example it is important to be generally fit before embarking on an activity such as skiing and the more one trains specifically for a particular sport, the less likely injury, in general, is likely to occur.

    Although sports are very specific in their requirements and the way in which a participant uses muscles, joints and balance, there is an overlap between some sports. For example cycling uses similar lower limb muscle activity to skiing and will offer some protection against injury for those of us who have been away from the slopes for a long time!

    A greater level of expertise in a particular sport will help to reduce the risk of injury and will particularly help to reduce the level of ACL injury, if combined with preventative programmes as mentioned above.

    Other factors relevant in preventing ACL injuries include

    1) Having the correct footwear for the surface you are playing on.
    2) Refusing to play on an unsafe surface, i.e. an icy &/or slippery surface.
    3) Warming up properly before participation.
    4) Making sure you are properly re-habilitated from a previous injury either to the same knee or another joint. A weak but painless ankle, for example, may lead to excessive adaptive pressure being put upon a knee and leading to a type II or III injury mentioned above.
    Other factors making you more or less likely to sustain ACL injuries.

    Gender: Sportswomen are more likely to suffer ACL injuries than sportsmen, although, as previously mentioned, a higher percentage of men than women have ACL injuries. Hormonal factors may have an influence on this and also the variation of connective tissues between individuals and the sexes.
    The sport being played. Some sports are far more likely to cause an ACL injury than others. Higher risk sports include skiing, where overly tight bindings may also have an influence along with other above mentioned factors, football & basketball, together with other twisting type sports. Lower risk sports include cycling, rowing, swimming and generally sports which involve straight line activity.
    What if an injury occurs to the ACL?

    If an injury occurs to the ACL the management varies considerably between individuals and ultimately the decision of ‘what to do’ needs to be taken by the person with the damaged knee and the more that person is informed the better. Most frequently an injured ACL presents with a lot of swelling, which comes on very soon after the injury occurs, because there is a lot of bleeding into the joint.

    The person usually has to stop their activity straight away and they normally have awareness that something is very wrong. There are exceptions to this, for example when there is partial damage to the ligament, i.e. it is not fully torn or perhaps where a previously partially torn ligament has a further insult and fully tears.

    There may also be circumstances where a player ‘blocks out’ an injury, perhaps because they are in the middle of a very competitive game, they have a high pain threshold and their anatomy allows them to (i.e. they have the correct joint shape and perhaps very good leg musculature.)

    When to have surgery or not.

    As mentioned above this decision can only be taken by the individual concerned and they need to be well advised by their Physiotherapist, Orthopaedic consultant or GP.

    There are factors which may make surgery essential, which could be ‘blocking’ of the joint, where after the initial swelling has settled the patient still can not achieve an acceptable range of motion in the joint, either on bending(flexion) and/or straightening (extension). This can be due to a variety of factors, most commonly that there is associated damage to the meniscus (semi-lunar or quarter moon shaped cartilage), which lies between the femur and the tibia in two distinct compartments, medial and lateral (towards the other knee or away from the other knee).

    The remains or stump of the damaged ACL ligament may also get in the way of normal joint movement or there could be associated bony damage to the tibia, femur or fibula or problems affecting the blood supply.

    It may not always be easy to determine the level of damage at an early stage and unless the blood supply or bone is compromised, (only likely in contact injuries), it is best to leave the joint and treat it with gentle Physiotherapy in the early stages, to try and restore the movement and to reduce the swelling. Ice and compression units can also be helpful with this.

    Once injured ACL knees have settled, it is easier to get a clearer picture of whether the knee may require surgical intervention.

    Magnetic Resonance Imaging (MRI) scans can be used at this stage, as the swelling will not cloud the pictures. Also physical testing of the knee, to ascertain damage, will be easier, as there will be less muscle spasm and pain inhibition stopping movement.

    The factors already mentioned would make surgery essential but many knees will achieve full range of motion and with good Physiotherapy the muscle strength around the knee should return.

    At this stage and with this group of patients who regain good movement and good muscular control at approximately a month after the injury, the decision of whether to have surgery or not needs to be considered.

    If the knee feels unstable and especially if it is repeatedly giving way and this situation is not improving with further Physiotherapy, then surgery should be considered.

    Other factors to be considered are sports played and the age of the patient. For example, if a nineteen year old footballer has an ACL injury, and wants to get back to playing the consideration is different from a forty year old player, who might consider changing sport to allow running &/or cycling, but not so much twist and turn.

    If there is associated damage to the meniscus and the individual returns to football, skiing or long distance running after a repair, there may also be an increased chance of early osteoarthritis. In this example the risk needs to be explained so that the patient may consider alternative sports or to go ahead and take the risk.

    If the patient elects not to have surgery Physiotherapy aims at regaining as much strength in the muscles around the knee as possible and to improve balance and proprioception, to try and avoid further insult to the knee or other joints.

    If, on the other hand, the patient decides to have surgery, it is advised to get the knee as strong as possible prior to the surgery (‘pre-hab’), which makes it easier in the aftermath of the operation, for the patient to return to familiar exercises.

    Once these exercises are easily achievable rehabilitation can normally begin in earnest. It must be explained to the patient that this will take about ten months and will require a lot of work on their behalf. Performing home exercises and visiting their Physiotherapist for updates of exercise, during this period is essential. Successful rehabilitation requires adherence to this, otherwise the knee may never regain full capability and this places other joints and the operated knee at unnecessary risk.

    In conclusion, it is better to avoid injury to the ACL with preventative programmes, if an injury occurs there needs to be an informed decision about surgery and if surgery does occur there need to be proper physiotherapy led rehabilitation and this needs to be explained to the patient by the medical team.