My knee hurts, what is it?

This is probably the sort of generic question that a physiotherapist can be asked and be expected to answer based on that one statement, that they dread!

It is equally more worrying when other people have had a similar joint problem who believe that it must be the same as their problem, give them advice as a good friend and they either don't get better or dare we say, get worse! Why? because there is more than one pathology (condition) that a knee or in fact any other joint could have! And if we get the diagnosis wrong and give the wrong exercises based on that, you can actually set the rehabilitation back!

Firstly, let's take a look at the anatomy of the knee complex:

Although at first glance, it does look fairly simple, comprising of just 4 ligaments:

anterior cruciate ligament (ACL)

posterior cruciate ligament (PCL)

medial collateral ligament (MCL)

lateral collateral ligament (LCL)

Not forgetting the meniscus, which acts like a cushion in the joint

And 5* significant groups of muscles that attach and move the knee:

Quadriceps - straighten the knee

Hamstrings - bend the knee

Calves - Plantar flex (point your toes down) and help to bend the knee

Ankle Dorsiflexors - (lift your toes up)

Gluteals - straighten the hip, amongst numerous other roles+

*Simplified for ease of blogging purposes.

Yet, it's called a knee complex because it comprises of three joints:

Femur (thigh) and patella (knee cap) called the patella-femoral joint

Femur (thigh) and tibia (shin) called the tibio-femoral joint. Sometimes known as the true knee joint

Tibia (shin) and fibula (small shin) called the superior tibio-fibular joint

I remember in my formative years, a colleague said to me in general:

"If a physio thinks rehabilitating the knee is easy, then they don't understand the knee!!"

And, he was right!

Despite it's initial simplicity in appearance, as you can see there are many structures involved in the knee that could be causing your pain and discomfort. Let me try to explain a couple of pathologies that you do not want to mix up, because the treatment is so different and one can make the other worse!

In the image to the right, the structure highlighted in red in the patella tendon. If this is the source of your problem then you are most likely to have patella tendinopathy. Research has shown, like any tendinopathy, in order to rehabilitate this, it needs to be worked under load, to increase its tensile load and stop the pain. In order to rehabilitate this, we need to perform closed chain exercises or weight bearing exercises.

However, if the pain appears to be coming from inside the knee and it is painful to push down on the knee, then you are likely to have patella bursitis (inflammation of the bursa [ fluid filled sac]). If this is the case, then we need to perform open chain exercises or non-weight bearing exercises. If you were to perform weight bearing exercises for bursitis, you will make the problem worse! If you did open chain exercises for patella tendinopathy, you won't get better!

+ Now, let's not forget the gluteals. You may have noticed above that the gluteals do not have a significant role in knee movement (for those in the know, yes they assist in medial and lateral rotation of the knee) yet they are extremely important for knee rehabilitation, like many lower limb pathologies. The source of your knee pain could be coming from weakened gluteals which affects the biomechanical chain, meaning your weight is not distributed evenly through the joint, causing your pain, so don't be confused or dismissive if your clinician gives your "bum strengthening" exercises. Then again, a good clinician should explain this to you. So, I hope this goes a long way to explaining why it is not always that easy to diagnose, advise and suggest the correct exercises based on "My knee hurts, what is it?" It is always in your best interest to arrange an accurate, thorough assessment and be diagnosed correctly and given the right treatment first time, to aid your recovery and not set you back.

Particularly when the avid athlete who has had every injury known to man and knows how to treat it. Ask yourself why that person keeps getting injured and therefore is his advice necessarily the best and right advice for you?