Friday, 22 March 2013

Knee Injuries.

Knee Injuries

Let’s take a snapshot of each common injury and discuss them individually and then look ways of preventing them.

Cartilage (Meniscus) injury 
Found in your knee fixed to the top of the shin bone (tibia), the cartilage helps to stabilise the knee and help with cushioning when you land. They are commonly damaged in field sports when you are twisting and turning, but runners are prone to this too as they step off a curb or slip doing cross country for example. Typically your knee will buckle and then swell. Sometimes your knee locks and becomes difficult to move and bear weight through it. In these cases Rest, Ice, Compression and Elevation (R.I.C.E) can be helpful. A compressive knee sleeve at this point can be helpful when you are trying to minimise the swelling. Do see a Sports Injury Therapist or Sports Injury Doctor so a decision can be made as to whether conservative measures (R.I.C.E and exercises) will be enough to resolve the problem or whether surgery is indicated. It’s usually worth taking some time to try and get the swelling down and the knee stronger, even if surgery is going to be necessary, as it will heal better after the surgery if the knee is in better shape first.

Anterior Cruciate Ligament (ACL) injury 
This is one of a pair of ligaments in the knee, the other less well known ligament being the Posterior Cruciate Ligament (PCL). They attach from your thigh bone (femur) to your tibia and cross over in the knee and provide stability. They can do this physically by virtue of their attachments, but also by sending your brain useful information about the types of loads going through your knee via strain gauges (proprioceptors) as you move. This enables your brain to reflexly decide how much muscle force is required to control the knee during the task or sport you are performing. When your ACL gets injured these strain gauges switch off and so the knee becomes unstable as your brain doesn’t know how much load is going through the knee and so how much to activate the muscles. When you tear your ACL your knee can become swollen and painful in a similar way to that of a cartilage tear and feel very unstable.

Sometimes surgery isn’t necessary and if it’s not a bad tear, a good rehab programme by a specialist therapist is sufficient to allow a return to sport. You can find that knee bracing is helpful in particular phases of your recovery, so it’s worth discussing this with your therapist. Exercise like the ones in figs 1 and 2 can be very helpful at teaching your muscles to start to engage again. To help this further and to encourage the strain gauges in your knee to fire up again, standing on one leg with your eyes closed is very effective. This type of exercise with your eyes closed means that your eyes cannot help you make balance corrections and you have to rely on your strain gauges if your balance is to improve. Variations on this exercise theme can progressively improve your knee’s ability to provide the right information to your brain at the right time, to improve your balance and stability. Make sure you’re near something you can hold on to for safety reasons in case your balance needs working on!

If it comes down to it though, ACL surgery is now getting so good that it is not as scary a thought as it was 10 years ago.

A Plica is a fold of the synovial membrane, which is the inner lining of your knee joint. These folds are normal structures which develop while you are in the womb. They are often asymptomatic in most people but sometimes, usually following a minor injury such as a direct blow on the knee, the Plica becomes inflamed and scarred and can click as it slides across the surfaces of the joint. Running can then cause your knee to become painful and inflamed. The pain is usually on the inside of your knee around the knee cap (patella), but it can be on the outside too. Your knee can often click and become stiff and painful when held in the same position for prolonged periods, as with sitting. A knee support called an infra-patella brace can help to take the pressure off the tendon while it is healing and when you start to exercise again. Therapy can help this by massaging the thickened area of scarring, as can exercise, but sometimes surgery is required. This injury can be quite difficult to diagnose so make sure you’re specialist comes recommended. Exercises in fig 1 and 2 will help with a Plica and combine well with the massage to minimise the risk of surgery.

There are times though when these injuries do not present in the extreme way described above. Often these structures will become damaged gradually over time due to particular external forces, for example, incorrect shoes or faulty biomechanics (muscle imbalances, leg length discrepancies, tight calves etc). The affects our biomechanics have on our body and the vicious circle of injury and pain it can cause is one of the main reasons knee pain can be recurrent.

A rotated pelvis for example can go unnoticed for many years until the compensations start to cause problems. This abnormal pelvic position often causes one leg to appear longer or shorter and the body must compensate for this. Typically one way it compensates is to overly pronate the foot of the longer leg to try and shorten it, another way is to bend the knee more.

Unfortunately both of these options will increase the load on the knee. If the foot over pronates, it will likely cause the leg to internally rotate excessively and if this is a quick movement, knee problems are exaggerated. This rotation force (torque) will often be absorbed at the knee, which can result in pain. Alternatively if the knee bends too much during mid-stance phase as you run, this can de-stabilise the knee and it will naturally want to rotate inwards. If this is combined with an already over pronating foot, the problem is often exaggerated. Both of these situations are likely to result in knee pain.

It is often suggested that insoles (orthotics) can be helpful to reduce the pressure on the knees. Bear in mind that many causes of knee pain come from the pelvis and the biomechanical problems with your feet are often due to compensations for faulty hip or pelvic biomechanics. It is therefore important that before we start thinking about orthotics, we need to check out the hips and pelvis first. If not orthotics which could potentially be a good thing to help reduce the pressure on the knees, could likely aggravate it.

Managing these biomechanical issues is critical if your knee pain is to be managed and allow you to return to long term training and also to reduce the risk of recurrence. Please make sure you get these biomechanical issues checked by your local therapists as part of your rehab and conditioning programme.


I have noticed over recent weeks my knee has become sore under my knee cap. The band under it is very tender when I touch it and it gets worse either when I train or when I sit and watch TV. I’ve also noticed that the knee can be very stiff in the mornings too. What is it and what should I do?


It sounds like to you have damaged your patella tendon, it’s also known as patella tendinitis or Jumpers Knee. It usually occurs gradually if you over-practice jumping and landing type activities, but can also be caused when you up grade your training too quickly especially if it includes hill training or plyometrics.
Ice can help after a run, but longer term you will likely find that massage to the tendon can be very effective. If you find the tender spot and massage it most days for 2-3 mins, although tender at the time, the knee should feel looser and less painful afterwards. Over time this can have a positive effect on the knee. You often find that patella tendon straps help this too as they take the pressure off the tendon and allow it to heal. Many people also find that shock absorbing insoles help by minimizing the impact, especially if you run mainly on hard surfaces.
Last updated: 26-05-2012

No comments:

Post a Comment